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Category: Uncategorized

Tiagabine

Plain-language summaryIntrigue 50 / 100

Tiagabine (Gabitril) is a selective inhibitor of the GAT-1 GABA transporter, the protein that pulls GABA back into nerve cells after release. By blocking GAT-1, the drug prolongs the time GABA remains in the synapse and amplifies inhibitory signaling. It was approved by the FDA in 1997 as add-on therapy for partial seizures. Clinical adoption was modest because it does not work well as monotherapy and has a narrow effective dose window. It saw some off-label use for anxiety and sleep, but a paradoxical risk of inducing seizures in patients without epilepsy when used at off-label doses earned it an FDA warning in 2005. Mostly a research tool now for studying GABA transporter pharmacology. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundNiche research probe

51/100

Canonical GAT-1 probe with solid bench utility but negligible novelty as a discovery target

Look, tiagabine is one of those compounds that earns its place in a research library not because anyone is racing to study it, but because you cant study GAT-1 biology without it. Thats the whole story. Developed at Novo Nordisk and approved by the FDA in 1997 under the name Gabitril, its been the canonical selective GAT-1 inhibitor for nearly three decades. The selectivity profile is genuinely impressive: greater than 100-fold preference for GAT-1 over GAT-2 and GAT-3. That kind of selectivity makes it the reference standard when you need to isolate GAT-1-dependent GABA reuptake from the rest of the transporter family.

What we like mechanistically is the specificity. GAT-1 is the dominant neuronal reuptake transporter, and tiagabine lets you ask precise questions about phasic versus tonic inhibition, about extracellular GABA pooling, about slow-wave sleep induction. Vyazovskiy and colleagues have used it productively in sleep slow-wave amplitude work. That’s real bench value. It’s not flashy, but it’s the kind of probe that generates clean, interpretable data in the right hands.

Here’s the thing though: the research-excitement case is weak. The mechanism is mature and single-target. GAT-1 inhibition is not a new idea; its not a dual mechanism, not a mitochondrial angle, not tied to any of the hot current targets in metabolic, longevity, or neuroplasticity research. You know exactly what youre getting, which is the point for tool use and a liability for frontier research. Nobody is writing a grant in 2026 with tiagabine as the exciting part of the story.

The translational picture is mixed. In epilepsy it works, thats settled, approved, replicated across phase 3. The off-label anxiety angle is genuinely complicated. The FDA issued warnings about new-onset seizures at off-label doses, with roughly a 1 percent incidence in non-epileptic patients. That safety signal killed most of the off-label enthusiasm and limits how freely investigators can extrapolate findings. It doesnt make it unusable in research, but it does mean translational upside outside the seizure indication is constrained.

We think tiagabine belongs in any library that takes GABA transporter biology seriously. It’s not a compound you pitch to a study section as exciting; it’s a compound you pull off the shelf when your experimental design requires isolating GAT-1 function. Useful, established, non-redundant in its specific niche. The score reflects that exactly: not a destination, but an indispensable tool for investigators working in the space.

Novelty

22

Mechanism promise

38

In-category differentiation

58

Evidence quality

72

Translational signal

65

Research bench value

72

Rationale Tiagabine scores on the strength of its unique probe identity as the only widely-used GAT-1-selective inhibitor, but its 1997 approval date, well-trodden mechanism, and seizure-risk liability in off-label use drag novelty and translational scores down hard. The high differentiation and bench-value scores reflect its irreplaceable role in GABA transporter work, not research excitement.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

GAT-1 selective GABA reuptake inhibitor

A nipecotic acid derivative selective GABA reuptake inhibitor; the prototype GAT-1 transporter blocker.

Abstract

Tiagabine ((R)-1-[4,4-bis(3-methyl-2-thienyl)-3-butenyl]-3-piperidinecarboxylic acid; CAS 115103-54-3; molecular formula C20H25NO2S2; molecular weight 375.55) is a nipecotic acid derivative selective inhibitor of the GABA transporter GAT-1, developed at Novo Nordisk and approved by the FDA in 1997 under the trade name Gabitril. Mechanism: high-affinity inhibition of GAT-1 (the principal neuronal GABA reuptake transporter) prolongs synaptic GABA availability after release, enhancing GABA-A and GABA-B receptor activation. Selectivity for GAT-1 over GAT-2 and GAT-3 is greater than 100-fold. Plasma half-life is 7 to 9 hours; metabolism is via CYP3A4. Approved as adjunctive therapy in partial-onset seizures in patients aged 12 and older. Off-label use in generalized anxiety disorder has been complicated by FDA warnings of new-onset seizures in patients without epilepsy (incidence approximately 1 percent at off-label doses). Used as the canonical GAT-1 selective inhibitor in mechanism studies.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

May 9, 2026
Yohimbine

Plain-language summaryIntrigue 55 / 100

Yohimbine is an alkaloid extracted from the bark of an African tree (Pausinystalia johimbe), used historically as an aphrodisiac. Pharmacologically it is an alpha-2 receptor blocker, which means it does the opposite of clonidine: it ramps up the sympathetic nervous system, raising noradrenaline release. At low doses it can produce alertness, anxiety, and a small erectile-function benefit; at higher doses it triggers panic-like states and is used in research as a deliberate panic challenge. Sold widely as a fat-loss and pre-workout supplement, with mixed clinical evidence. The pressor and anxiogenic effects make it dangerous for people with cardiovascular disease or anxiety disorders. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundNiche research probe

41/100

The canonical alpha-2 pharmacological probe; low novelty but durable bench utility for noradrenergic research programs

Look, yohimbine isn’t a compound you discover. It’s one you already know. The alpha-2 adrenergic antagonist literature is old enough to be cited in textbooks that are themselves dated, and yohimbine sits at the center of that literature as the reference standard. That’s both its greatest asset and the reason its overall research merit sits in the low 40s.

The mechanism is textbook. Presynaptic autoinhibition blockade, increased noradrenergic outflow, downstream cascade of blood pressure elevation, anxiety, tachycardia, mydriasis. Nobody is writing a grant to characterize the mechanism of yohimbine. The pharmacology has been settled for decades. What keeps it alive is the same thing that keeps ketamine alive after decades of use: sometimes you need the probe more than you need the novelty.

Where yohimbine earns its keep is the panic disorder provocation paradigm. Charney’s group at Yale, and multiple independent replications, have used IV yohimbine challenges to map noradrenergic dysregulation in PTSD, panic disorder, and stress-sensitization models. The selectivity profile is clean, roughly 50-fold alpha-2 over alpha-1 (Ki approximately 1 to 5 nM versus alpha-1), and the short plasma half-life of around 0.6 hours gives investigators temporal control that a longer-acting compound would undermine. That’s genuine bench-to-clinic utility. It doesnt generate new biology, but it lets you interrogate existing biology with real precision.

The therapeutic end is considerably weaker. The erectile dysfunction angle, which accounts for most of its commercial footprint, has an evidence base that consistently underdelivers. Multiple controlled trials show inconsistent effects and modest effect sizes that wouldn’t satisfy a high-standard systematic review. The secondary 5-HT1A partial agonism at around 100 nM adds theoretical texture but doesn’t meaningfully shift the clinical picture.

What we like: the compound is well-characterized, dosing windows and washout periods are firmly established across decades of human pharmacology studies, and purity from pharmaceutical-grade suppliers is reliable. If your lab is running any kind of noradrenergic activation study or a sympathetic challenge protocol, yohimbine is still the tool you reach for. thats not nothing.

What we don’t like: there is essentially nothing new here. No serious group is exploring genuinely novel indications, the mechanism space is fully occupied, and sourcing from OTC channels introduces purity variance that can undermine experimental control. For investigators specifically working on noradrenergic circuits or panic neurobiology, yohimbine is necessary. For everyone else, it’s a reference standard worth knowing and not much more.

Novelty

20

Mechanism promise

28

In-category differentiation

42

Evidence quality

58

Translational signal

48

Research bench value

68

Rationale Yohimbine scores low on novelty and mechanism freshness because the alpha-2 antagonism story is textbook-settled, but its bench value lifts the overall via genuine indispensability in noradrenergic and panic-biology provocation paradigms. No scheduling or category cap applies; the 41 reflects a compound that earns its place as a probe, not as a discovery target.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

Selective alpha-2 adrenergic antagonist

An indole alkaloid alpha-2 adrenergic antagonist from Pausinystalia johimbe; the canonical pharmacological probe for noradrenergic activation.

Abstract

Yohimbine (17-alpha-hydroxy-yohimban-16-alpha-carboxylic acid methyl ester; CAS 146-48-5; molecular formula C21H26N2O3; molecular weight 354.45) is an indole alkaloid isolated from the bark of Pausinystalia johimbe (Rubiaceae) and from Rauwolfia species. The compound is a selective alpha-2 adrenergic antagonist (Ki approximately 1 to 5 nM) with secondary 5-HT1A partial agonism (Ki approximately 100 nM); selectivity for alpha-2 over alpha-1 is approximately 50-fold. Pharmacologically, yohimbine increases central noradrenergic outflow by blocking presynaptic autoinhibition, producing anxiety, increased blood pressure, mydriasis, and tachycardia. Used in clinical research as a provocation test for panic disorder (where vulnerability to alpha-2 antagonism predicts panic susceptibility) and as a positive control in studies of noradrenergic regulation. Folk use as an aphrodisiac for erectile dysfunction has limited supporting evidence. Plasma half-life is approximately 0.6 hours. Used as the canonical alpha-2 antagonist in academic pharmacology.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

May 9, 2026
Exemestane

Plain-language summaryIntrigue 60 / 100

Exemestane (Aromasin) is the third major aromatase inhibitor, approved in 1999. It is mechanistically distinct from anastrozole and letrozole: rather than competitively binding aromatase, it is a substrate analog that the enzyme starts to process but cannot release, becoming permanently inactivated (a so-called suicide inhibitor). Recovery requires the body to make new aromatase, so the effect outlasts any individual dose. Estradiol suppression is comparable to letrozole. Because it has a steroid backbone, exemestane retains weak androgenic activity, which some users perceive as a side effect (acne, oily skin) and others as a feature. Used in postmenopausal breast cancer and off-label by steroid users. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundEstablished, active research

57/100

Canonical steroidal suicide aromatase inhibitor; irreversibility is its one genuinely distinctive research handle

Look, exemestane is a genuinely elegant compound that sits in an awkward position for a research library: it’s been approved since 1999, the mechanism is textbook, and its clinical career in ER-positive breast cancer is thoroughly documented. What saves it from being merely a historical footnote is the specificity of what it does. This isn’t just an aromatase inhibitor in the broad sense; it’s a covalent, mechanism-based suicide inhibitor. The enzyme commits to catalyzing the substrate, gets trapped mid-reaction, and cant recover without de novo synthesis. That irreversibility is actually interesting from a probe standpoint in ways anastrozole and letrozole simply cannot match.

The steroidal scaffold is the key differentiator. Anastrozole and letrozole are both triazole-based, non-steroidal, and reversible. Exemestane is a substrate analog of androstenedione: the enzyme recognizes it, starts processing it, and gets covalently inactivated. Researchers studying aromatase recovery kinetics, enzyme turnover rate, or tissue-specific estrogen synthesis have a tool here that lets them ask questions reversible inhibitors cant answer. You can ablate activity and watch it come back over days as new enzyme is synthesized. Thats a different experimental handle than competitive inhibition, and in the right study design it’s actually the right tool.

The weak androgenic activity from the steroidal scaffold is a detail that gets underplayed. It contributes to the distinct side effect profile observed clinically, and in a research context it introduces a variable that investigators studying androgen/estrogen balance need to account for. We think that complexity is both a feature and a limitation, depending on the experimental question. It’s not a clean probe the way a pure competitive inhibitor would be, and studies that want to isolate aromatase inhibition without any androgenic confound will need to think carefully about that.

Evidence quality here is essentially as strong as it gets: the IES trial, NCIC MA.27 head-to-head versus anastrozole, multiple adjuvant comparisons with long-term follow-up. This is an approved drug with decades of oncology-grade RCT data. That drives the evidence and translational scores up considerably. Where exemestane loses ground in this rubric is novelty: there’s nothing fresh to explore in the primary mechanism space, and the mainstream indication is fully mature. The interesting open questions are relatively narrow, centering on non-cross-resistance versus non-steroidal AIs after progression, male hypogonadism management contexts, and the androgenic tissue-balance story in specific experimental models.

We’d reach for exemestane as a research compound specifically when the irreversibility of aromatase inhibition is the experimental requirement. For anything broader, the more novel corners of steroidogenesis and estrogen biology have more open questions right now. Solid, well-characterized, defined use case; not a frontier compound.

Novelty

22

Mechanism promise

42

In-category differentiation

65

Evidence quality

82

Translational signal

78

Research bench value

68

Rationale Exemestane scores low on novelty (FDA approved 1999, fully mature primary literature) but earns real credit for mechanism-based differentiation as the only approved steroidal suicide AI and for bench utility as an irreversible aromatase probe. Strong RCT evidence base and clear clinical translational signal keep the overall score from falling further.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

Steroidal (suicide) aromatase inhibitor

A steroidal mechanism-based aromatase inhibitor; irreversibly inactivates aromatase by covalent suicide adduction.

Abstract

Exemestane (6-methylenandrosta-1,4-diene-3,17-dione; CAS 107868-30-4; molecular formula C20H24O2; molecular weight 296.40) is a steroidal third-generation aromatase inhibitor developed at Pharmacia (now Pfizer) and approved by the FDA in 1999 under the trade name Aromasin. Distinct from anastrozole and letrozole by mechanism: exemestane is a substrate analog of androstenedione that aromatase begins to process but cannot release, producing irreversible covalent inactivation of the enzyme. Recovery of aromatase activity requires de novo enzyme synthesis. Plasma estradiol suppression is comparable to anastrozole (approximately 85 to 95 percent at 25 mg daily). The steroidal scaffold confers weak intrinsic androgenic activity and unique side effect profile (less estrogen-deprivation symptoms in some patients). Plasma half-life is approximately 24 hours; metabolism is hepatic via CYP3A4. Approved for adjuvant and metastatic ER-positive postmenopausal breast cancer. Used as the canonical steroidal suicide aromatase inhibitor in mechanism studies.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

May 9, 2026
Cagrilintide

Plain-language summaryIntrigue 75 / 100

Cagrilintide is a long-acting amylin analog from Novo Nordisk, built by attaching a fatty-acid chain to a modified amylin so it binds plasma albumin and circulates for about a week (versus less than an hour for native amylin). It uses the same long-acting trick as semaglutide. The strategic value is that combining cagrilintide with semaglutide hits both the GLP-1 and amylin systems, and phase 2 trials of the combination (CagriSema) showed weight loss exceeding semaglutide alone, approaching tirzepatide territory. Phase 3 trials are ongoing. The amylin axis is a credible second front in obesity treatment alongside the incretins. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundNovel, promising

64/100

First long-acting amylin agonist with serious clinical data, best used in combination with GLP-1 agents

Look, cagrilintide has a legitimate claim to being the most interesting amylin compound in the space right now, which isnt saying that much given how thin the long-acting amylin field has been until very recently. Pramlintide has been around since 2005 and requires three injections a day; that practical burden alone kept the amylin receptor largely unexplored as a serious obesity pharmacology target. Cagrilintide’s C18 fatty acid modification for albumin binding solves the half-life problem entirely, extending from under an hour for native amylin to roughly seven days. That’s a real pharmacological advance built on a proven albumin-binding strategy, and its the reason this compound deserves serious attention.

The mechanism is worth taking seriously on its own terms. Amylin acts through the area postrema and nucleus tractus solitarius, slowing gastric emptying and generating satiety signals through brainstem circuits that are largely distinct from where GLP-1 receptor agonists engage. When you combine these, you’re hitting complementary central satiety pathways at different neuroanatomical levels and with different temporal profiles. That’s the rationale behind the CagriSema phase 2 data showing up to 17 percent body weight loss at 32 weeks, approaching the magnitude of bariatric surgery outcomes. The fact that this exceeds what semaglutide produces alone at comparable doses suggests genuine additive pharmacology rather than simple dose escalation of overlapping mechanisms. For an investigator interested in the neurobiology of appetite and energy balance, that complementary signal is the most interesting thing going in metabolic pharmacology right now besides the triple agonists.

What holds the overall score back is honest accounting. Cagrilintide as a standalone is less compelling than in combination. The amylin receptor literature is still thin, basic downstream signaling questions are unresolved, and the REDEFINE phase 3 program will answer questions the phase 2 data deliberately left open. Single developer means external replication of core efficacy claims is limited. We also dont have a clean experimental separation of how much of CagriSema’s effect is driven by cagrilintide specifically versus interaction terms with semaglutide, and that separation is a real and tractable research problem.

Differentiation from pramlintide is enormous on practical grounds. Differentiation from the dual-agonist incretins depends on whether complementary amylin pharmacology adds clinically meaningful efficacy beyond what GIP/GLP-1 dual agonism already captures. That question is unresolved and genuinely worth bench time. For investigators building an obesity pharmacology program, probing central satiety circuitry, or evaluating combination incretin strategies, cagrilintide belongs in the toolkit. For most other research programs, its relevant only at the periphery. Honestly, phase 3 readout will move this score considerably in one direction or the other.

Novelty

60

Mechanism promise

68

In-category differentiation

65

Evidence quality

58

Translational signal

68

Research bench value

60

Rationale Cagrilintide scores on genuinely distinct mechanism and strong phase 2 combination signal, but is held back by single-developer context, phase 3 pending, and the fact that its most compelling data is combinatorial rather than standalone. The amylin receptor space was nearly dormant before this compound, which adds novelty points, but also means the surrounding literature is thin.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

Long-acting amylin analog

A long-acting amylin analog with attached fatty acid for albumin binding; under development as an obesity treatment in combination with semaglutide.

Abstract

Cagrilintide (CAS 1415456-37-9; modified amylin analog with C18 fatty acid attached at lysine for albumin binding; molecular weight approximately 4870 Da) is a long-acting amylin receptor agonist developed by Novo Nordisk for obesity. The compound is structurally derived from pramlintide with addition of a C18 fatty acid linker for albumin binding (the same long-acting strategy as semaglutide), extending plasma half-life from less than 1 hour for amylin to approximately 7 days for cagrilintide. Phase 1 and 2 trials in obesity demonstrated dose-dependent weight loss; in combination with semaglutide (the CagriSema combination), phase 2 trials showed up to 17 percent body weight loss at 32 weeks, approaching the magnitude of bariatric surgery. Phase 3 trials (REDEFINE program) are ongoing. Plasma half-life supports once-weekly subcutaneous dosing. Used as the prototype long-acting amylin agonist in metabolic research.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

May 9, 2026
Sulbutiamine

Plain-language summaryIntrigue 50 / 100

Sulbutiamine (Arcalion) is essentially two thiamine (vitamin B1) molecules joined by a disulfide bridge, developed in Japan in the 1960s. The dimerization makes the molecule fat-soluble enough to cross the blood-brain barrier readily, where regular thiamine struggles to penetrate. In the brain it is broken down to free thiamine, raising central thiamine levels and supporting the thiamine-dependent enzymes of glucose metabolism. Approved in France, Russia, and several Asian markets for asthenia (loosely, fatigue states). Used as a nootropic and anti-fatigue supplement. Clinical evidence is largely from older French and Russian trials of uneven quality. Tolerance can develop with daily use. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundEstablished workhorse

32/100

A 1960s approved thiamine prodrug with real BBB advantage but little modern research pull

Look, sulbutiamine is a 1960s Japanese pharmaceutical, approved under the name Arcalion in France and parts of Asia for psychogenic asthenia, and thats roughly where the exciting story ends. The compound is a disulfide dimer of two thiamine molecules. The entire pharmacological premise is that standard thiamine crosses the blood-brain barrier poorly, and sulbutiamine, being highly lipophilic, does it better. Once inside, it breaks down to thiamine and isobutyric acid, raising brain thiamine levels and supporting the usual cast of thiamine-dependent enzymes: transketolase, pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase. Thats the mechanism. Its not a bad mechanism. Its just not a novel or particularly exciting one in 2026.

The clinical evidence is real but uneven. The asthenia trials, mostly from French-language literature in the 1980s and 1990s, show a genuine signal for subjective fatigue reduction. Some smaller trials have looked at declarative memory and cholinergic function. What we don’t like is that the methodology across this literature ranges from acceptable to pretty rough, and the effect sizes are modest. This is not a compound generating serious phase 2 or 3 RCT programs right now. It’s an old approved drug in a sleepy indication.

Differentiation is the real problem here. If a researcher wants to study central thiamine deficiency biology, sulbutiamine is one tool. But benfotiamine is a serious competitor for the thiamine-analog niche, with arguably stronger peripheral evidence (diabetic neuropathy work) and comparably good CNS penetration in some assays. The sulbutiamine-versus-benfotiamine debate in the nootropic community has never been resolved cleanly because neither compound has the trial base to settle it. Neither dominates. Sulbutiamine has the unique angle of the disulfide structure and the specific Arcalion approval history, but that angle doesn’t translate into bench-scale excitement.

Honestly, the bench value is real but narrow. Sulbutiamine is useful if your research program specifically concerns central thiamine-dependent pathways or if you’re working on prodrug strategies for BBB-impaired cofactor delivery. It’s a cleaner CNS probe than raw thiamine HCl. But it’s not an indispensable tool and it’s not answering questions that couldn’t otherwise be approached. The nootropic community’s enthusiasm for it has never really been matched by independent academic interest, which tells you something. We’d prioritize this only for investigators with a specific thiamine biology question and good reason to prefer the lipophilic route over benfotiamine or thiamine pyrophosphate supplementation studies.

Novelty

22

Mechanism promise

22

In-category differentiation

32

Evidence quality

42

Translational signal

45

Research bench value

35

Rationale Sulbutiamine earns the ‘novel form’ exemption from the generic B1 cap because the lipophilic BBB story is legitimately distinct from plain thiamine, but that exemption doesn’t rescue the score. Novelty, mechanism, and differentiation all land low because the entire research case reduces to ‘more thiamine in the brain via prodrug chemistry,’ the clinical evidence for asthenia is real but methodologically patchy, and benfotiamine competes seriously for the same CNS-thiamine niche. An established-mature rating reflects a known approved compound with honest but modest research value.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

Synthetic disulfide thiamine derivative

A lipophilic disulfide thiamine analog that crosses the blood-brain barrier; developed in Japan for asthenia and used as a nootropic.

Abstract

Sulbutiamine (isobutyryl thiamine disulfide; CAS 3286-46-2; molecular formula C32H46N8O6S2; molecular weight 702.89) is a synthetic disulfide derivative of thiamine (vitamin B1) developed in Japan in the 1960s and approved in several Asian and European markets under the trade name Arcalion. The compound is structurally a dimer of two thiamine molecules joined by a disulfide bridge, conferring high lipophilicity and improved blood-brain barrier penetration compared to thiamine itself. Mechanism: thiamine prodrug; sulbutiamine is metabolized to thiamine in the brain, raising central thiamine concentrations and supporting thiamine-dependent enzymes (transketolase, pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase). Clinical use is in psychogenic asthenia and as a nootropic; evidence is from clinical trials with mixed methodology. Plasma half-life is approximately 5 hours. Used as a lipophilic thiamine prodrug in research and nootropic communities.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

May 9, 2026
HU-308

Plain-language summaryIntrigue 52 / 100

HU-308 is a synthetic cannabinoid built by the Mechoulam laboratory in Jerusalem to bind the CB2 receptor about 440 times more tightly than CB1. CB2 receptors live mostly on immune cells outside the brain, so a CB2-selective compound activates immune signaling without producing the psychoactive high that comes from CB1 engagement. It is used almost exclusively as a research probe to dissect what CB2 does in inflammation, bone metabolism, and tissue protection, and to validate CB2 as a drug target without confounding CB1 effects. Not a clinical compound; lives entirely in the lab. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundNiche research probe

46/100

The canonical CB2-selective research probe; solid bench utility but aging mechanism and thin clinical translation

HU-308 earns its place in the library not because it’s exciting to read about in 2025, but because it’s genuinely hard to do rigorous CB2 pharmacology without it. Mechoulam’s group at Hebrew University synthesized it in the late 1990s, right when CB2’s immune-centric expression pattern was starting to attract serious attention. The pinene scaffold, the dimethoxyphenyl substitution, the greater-than-440-fold selectivity over CB1 – that selectivity profile is why it became the canonical probe. Before HU-308 and a handful of contemporaries, clean CB2 pharmacology was difficult to isolate from psychoactive CB1 noise. It solved a real experimental problem, and that problem is still real.

The mechanism story is fully mapped: Gi/o coupling, cAMP suppression, ERK activation in macrophages, microglia, B cells, T cells. CB2 sits at the intersection of peripheral immune modulation and pain signaling, so there’s real biology to interrogate. Anti-inflammatory effects in IBD models, neuropathic pain attenuation, hepatoprotective signal in ischemia-reperfusion – these aren’t trivial endpoints. Multiple labs have replicated the basic pharmacology across years and species. That cross-lab replication actually matters for a probe compound, and its one of HU-308’s strongest selling points.

What holds it back on the overall score is the translational picture. The CB2 agonist class has had a rough time moving from bench to bedside. Several CB2-selective programs in pain and inflammation have entered clinical trials and returned mediocre or null efficacy data. The biology appears real but translation has proven harder than preclinical data suggested. HU-308 itself isnt a development candidate at this point – its role is as a research tool, not a lead compound, and the overall field hasn’t validated the clinical hypothesis cleanly.

Honestly, the novelty picture is modest. This compound is over two decades old, the mechanism is fully characterized, and the receptor expression atlas is well-understood. If you’re scoring on frontier excitement it doesn’t compete with mitochondrial peptides or novel incretin scaffolds. What we think keeps it relevant is that CB2 biology keeps generating new questions – neuroinflammation, microglial activation states, peripheral sensitization in chronic pain – and HU-308 remains a clean way to ask those questions without psychoactive confounds contaminating your readout.

For a lab running a CB2-focused program, it’s essentially indispensable. For someone probing whether the CB2 axis is implicated in their disease model, it’s the correct tool. Outside of those use cases, theres limited reason to reach for it. The bench value score reflects the genuine indispensability within its niche; the overall score reflects that the niche is real but narrow, and the mechanism age and clinical translation struggles pull the compound well below frontier territory.

Novelty

32

Mechanism promise

40

In-category differentiation

62

Evidence quality

48

Translational signal

32

Research bench value

70

Rationale HU-308 scores well on bench value because it remains the go-to CB2 probe for clean pharmacology without CB1 confounds, but novelty is low for a 25-year-old compound with a fully mapped mechanism, and the CB2 agonist class has underdelivered in clinical translation, keeping evidence and translational scores modest.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

Synthetic CB2-selective cannabinoid

A synthetic CB2-selective cannabinoid agonist; a research tool for CB2 pharmacology without psychoactive CB1 activity.

Abstract

HU-308 ([4-[4-(1,1-dimethylheptyl)-2,6-dimethoxyphenyl]-6,6-dimethyl-bicyclo[3.1.1]hept-2-en-2-yl]methanol; CAS 256934-39-1; molecular formula C27H42O4; molecular weight 430.62) is a synthetic CB2-selective cannabinoid agonist developed by Mechoulam and colleagues at Hebrew University. The compound is a pinene-scaffold cannabinoid with high CB2 affinity (Ki approximately 23 nM) and minimal CB1 binding (greater than 440-fold selectivity), eliminating the psychoactivity associated with CB1-mediated cannabinoid effects. CB2 is expressed predominantly in peripheral immune cells (macrophages, B cells, T cells, microglia in CNS); selective activation produces anti-inflammatory and analgesic effects without psychotropic side effects. Preclinical studies demonstrate efficacy in inflammatory bowel disease, neuropathic pain, hepatic ischemia, and atherosclerosis models. Plasma half-life is approximately 2 to 3 hours. Used as the canonical CB2-selective research probe in academic immunology and pain research.

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May 9, 2026
Propofol

Plain-language summaryIntrigue 60 / 100

Propofol is the workhorse intravenous induction anesthetic used in most operating rooms and procedural sedation suites in the world. It enhances GABA-A receptor signaling at a unique binding site and produces rapid loss of consciousness within seconds of injection, with quick recovery as the milky lipid emulsion redistributes from brain to fat. It is also famous, unfortunately, as the agent involved in Michael Jackson’s 2009 death from physician-administered home use. The drug has a narrow therapeutic margin between sedation and respiratory arrest, which is why it is restricted to clinicians trained in airway management. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundNiche research probe

53/100

Canonical IV anesthetic with real consciousness-research probe value but zero frontier novelty

Look, propofol is not a research mystery. It’s been the dominant induction anesthetic since Diprivan’s 1989 FDA approval and the compound’s core pharmacology has been understood for decades. 2,6-diisopropylphenol acts as a positive allosteric modulator at GABA-A receptors, but at a binding site that is genuinely distinct from the benzodiazepine, barbiturate, and neurosteroid sites. That detail actually matters. The propofol site, sometimes called the inter-subunit transmembrane site, has been the subject of real structural biology work, including cryo-EM studies from the Bhatt and Bhatt-adjacent groups characterizing bound states in heteromeric receptor assemblies. So there is a legitimate probe story here, even if the compound itself isnt new.

Here’s the thing though: the mechanism promise scores low not because the science is bad, but because the pharmacology is completely mapped. Enhancing GABA-mediated chloride conductance, producing CNS depression in a dose-dependent and titratable way, is about as well-understood as anesthetic biology gets. There’s no dual-target angle, no novel receptor crosstalk, no emerging mechanism that a bench scientist would describe as surprising in 2025. What propofol does, it does well, and everyone knows how it does it.

The evidence picture is as strong as it gets outside of a vaccine trial. Decades of multi-center clinical use, stringent pharmacovigilance, post-market safety data from millions of procedures. The propofol infusion syndrome literature is a good example of how mature this drug is: the rare but serious metabolic acidosis and rhabdomyolysis syndrome has been characterized, risk-stratified, and built into clinical protocols. You can’t say that about a compound at the frontier. The translational arrow points straight down from bench to bedside and has for thirty years.

We think the real argument for keeping propofol in a research library is its value as a consciousness probe. No other IV agent gives investigators such clean, titratable, reversible control over conscious state while maintaining a reasonable pharmacokinetic profile. The biphasic elimination (distribution half-life of 2 to 4 minutes, elimination half-life of 3 to 12 hours) lets researchers bracket discrete windows of conscious and unconscious processing in ways that simply aren’t possible with most agents. Groups studying neural correlates of consciousness, notably the work coming out of the Mashour lab at Michigan and Koch’s group at the Allen Institute, have used propofol sedation as their standard tool for titrated depth studies. Thats genuine bench value.

What we dont like from a library-building standpoint: sourcing propofol for bench use is tightly controlled because it’s a pharmaceutical product, not a research peptide, and the emulsion formulation complicates most non-anesthetic applications. You’re not doing propofol-based cell biology at the bench in any straightforward way. Its score reflects a compound that earns its place as a reference probe and a benchmark in GABA-A structural work, but can’t credibly compete for investigator attention alongside genuinely novel targets. An interesting tool. Not an interesting discovery.

Novelty

18

Mechanism promise

28

In-category differentiation

60

Evidence quality

85

Translational signal

78

Research bench value

70

Rationale Propofol is a fully-translated, FDA-approved clinical agent with an exceptionally deep evidence base and genuine bench utility as a consciousness probe, but it scores very low on novelty and mechanism promise because the pharmacology is mature and the primary indication is completely settled. The score reflects its dual identity: workhorse anesthetic with a residual research angle, not a discovery target.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

GABA-A receptor positive allosteric modulator (intravenous anesthetic)

An alkylphenol intravenous general anesthetic; the most widely used induction anesthetic and the agent in Michael Jackson’s death.

Abstract

Propofol (2,6-diisopropylphenol; CAS 2078-54-8; molecular formula C12H18O; molecular weight 178.27) is an alkylphenol intravenous general anesthetic developed at ICI (now AstraZeneca) and approved by the FDA in 1989 (Diprivan). The compound is a GABA-A receptor positive allosteric modulator at a unique propofol-binding site distinct from the benzodiazepine, barbiturate, and steroid sites; the result is enhanced GABA-mediated chloride conductance and pronounced CNS depression. Formulation is a 1 percent oil-in-water emulsion (the source of the milky appearance). Plasma half-life is biphasic: rapid distribution (2 to 4 minutes) and slower elimination (3 to 12 hours). Approved indications: induction and maintenance of general anesthesia, sedation in ICU. Misuse for amateur sedation is associated with the death of Michael Jackson (2009). Propofol infusion syndrome (rare) involves metabolic acidosis, rhabdomyolysis, and cardiac failure with prolonged high-dose use. Used as the canonical IV anesthetic in research and clinical practice.

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May 9, 2026
Domagrozumab

Plain-language summaryIntrigue 50 / 100

Domagrozumab (PF-06252616) is Pfizer’s second-generation anti-myostatin antibody, designed for higher affinity than stamulumab. The pivotal phase 2 trial in Duchenne muscular dystrophy (2018) showed meaningful muscle mass increases on MRI but failed to demonstrate functional benefit on the primary motor outcome, leading Pfizer to terminate the program. The pattern (muscle mass without function) has now repeated across nearly every anti-myostatin compound tested in muscular dystrophy and is the central puzzle of the field: blocking myostatin reliably grows muscle but does not seem to make patients meaningfully stronger. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundNiche research probe

32/100

Failed DMD phase 2 retained as a selective myostatin probe for mechanistic research

Look, the anti-myostatin story has not gone well for anyone. Wyeth’s stamulumab, Lilly’s landogrozumab, Regeneron’s trevogrumab – the list of humanized antibodies that neutralized myostatin beautifully in animals and then failed in humans is long enough now that we have to take the lesson seriously. Domagrozumab is the Pfizer entry in that cohort, and its 2018 phase 2 in DMD produced the most clinically instructive kind of failure: muscle mass went up on MRI, but the 6-minute walk test and North Star Ambulatory Assessment didn’t move.

That result isnt just a dead end – its actually the most scientifically interesting thing about this compound. It suggests the limiting factor in DMD isnt myostatin-mediated mass suppression; its the relentless mechanical damage from dystrophin deficiency. You can add muscle, and the dystrophic fiber still breaks down faster than myostatin inhibition can compensate. Thats genuinely clarifying biology, and domagrozumab helped establish it.

The novelty problem is real. Myostatin inhibition as a concept is nearly thirty years old – the McPherron double-muscle mouse dates to 1997. The IgG1 antibody approach to neutralizing GDF-8 is well-trodden at this point, and domagrozumab doesnt have a mechanism angle that distinguishes it meaningfully from the compounds that came before. Its not doing anything the class hadn’t already tried, and the mechanism score reflects that: single-receptor neutralization in a saturated, largely-failed class.

Differentiation is the weakest score here. Against other anti-myostatin antibodies, domagrozumab occupies no particular best-in-class position. Its affinity for myostatin is high, it’s humanized, its PK in humans is characterized – that makes it a functional research tool, but not a leading one. We think the ActRII-pathway inhibitors (luspatercept, bimagrumab) are more interesting if you want to study muscle anabolism broadly, because they engage the wider TGF-beta ligandome and produce cleaner clinical signals.

What domagrozumab does retain is probe value for investigators who specifically want myostatin-selective inhibition, as opposed to the broader ligand traps that catch activin, GDF-11, and other TGF-beta family members alongside GDF-8. If your question is specifically about GDF-8 rather than the whole ActRIIB ligandome, this compound gives you a cleaner experimental handle. Thats a narrow utility but its real.

The phase 2 evidence is actually quality evidence – well-designed RCT, adequate N, prespecified functional endpoints – it just produced a negative answer. The evidence quality score is respectable for that reason. The translational signal, though, is genuinely negative: the mechanism did not translate to clinical benefit in the target population, and that distinction matters for how we weight this overall.

Bench scientists studying DMD pathophysiology, the myostatin signaling axis, or the dissociation between muscle mass and functional output in dystrophic tissue will find this a documented, human-characterized probe. For everyone else, the evidence has made the case for moving on.

Novelty

28

Mechanism promise

35

In-category differentiation

20

Evidence quality

50

Translational signal

22

Research bench value

48

Rationale Domagrozumab’s 2018 phase 2 in DMD decisively closed the clinical case: muscle mass increases on MRI did not translate to functional gains, and Pfizer walked away. Scores are suppressed by low novelty in a 25-year-old target class, no meaningful differentiation from other failed anti-myostatin antibodies, and a clearly negative translational signal; residual probe value for GDF-8-selective biology keeps bench_value from bottoming out.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

Anti-myostatin monoclonal antibody

A humanized anti-myostatin monoclonal antibody developed at Pfizer for Duchenne muscular dystrophy; phase 2 trial failed.

Abstract

Domagrozumab (PF-06252616; humanized IgG1 monoclonal antibody; molecular weight approximately 145 kDa) is a humanized anti-myostatin monoclonal antibody developed at Pfizer. The compound is selective for myostatin (GDF-8) with high affinity, designed to neutralize circulating myostatin in Duchenne muscular dystrophy. Phase 2 trial in DMD (2018) demonstrated muscle mass increases on MRI but no significant improvement in functional endpoints (6-minute walk test, North Star Ambulatory Assessment); Pfizer discontinued development. The trial result reinforced a broader concern about myostatin inhibition in DMD: muscle mass gains may not translate to clinical benefit if the underlying dystrophin deficiency continues to cause fiber damage. Used as a research compound for selective myostatin neutralization in DMD context.

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May 9, 2026
Riluzole

Plain-language summaryIntrigue 72 / 100

Riluzole was the first FDA-approved drug for ALS, cleared in 1995 and the only option until edaravone in 2017. It hits glutamate signaling from several angles at once: it blocks sodium channels (cutting glutamate release from nerve terminals), antagonizes AMPA and kainate receptors on the receiving end, and modestly potentiates GABA. Together these knock down the excitotoxic overdrive that researchers think kills motor neurons in ALS. The clinical effect is honest but small, extending median survival by roughly two to three months. That said, the benefit shows up consistently across trials, which matters. Off-label work has tested it in depression (inspired by ketamine’s glutamate-targeting success), generalized anxiety, and OCD. Reference glutamate-release inhibitor in neuropharmacology. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundResearch workhorse

49/100

First ALS approval and canonical glutamate release inhibitor with modest effect size and aging novelty profile

Look, riluzole is the compound that kept ALS patients alive a few months longer for nearly two decades, and thats no small thing historically. FDA-approved in 1995, first of its class for ALS, and the drug that forced a real conversation about excitotoxicity as a therapeutic target. We have real respect for what it accomplished. But respect and research novelty are different currencies, and the gap between them is where this score lives.

The mechanism is genuinely multi-target in a way that still holds interest: state-dependent sodium channel blockade reduces glutamate release from presynaptic terminals, combined with postsynaptic AMPA and kainate receptor antagonism and modest GABA-A potentiation. That’s a layered glutamate-reduction profile rather than a clean single-receptor hit. What we like about it mechanistically is precisely that layering, and the fact that it remains the canonical tool for presynaptic glutamate release inhibition in excitotoxicity research. You can’t replicate that role easily with other compounds, and that’s what keeps the bench value score honest.

Where riluzole gets harder to justify as a frontier pick is novelty. Thirty years of literature means the research community has turned it over many times. The ALS efficacy signal is real but modest, median survival extension measured in weeks to a couple of months across replicated trials. The excitotoxicity hypothesis it targets hasn’t produced dramatic new mechanistic territory since. Edaravone arrived in 2017, tofersen more recently. The differentiation case has softened considerably.

The more interesting current angle is off-label psychiatric use, particularly OCD, generalized anxiety, and major depressive disorder. Pittenger’s group at Yale and others have run small-N trials in treatment-resistant OCD with meaningful response rates, and the glutamate hypothesis of MDD has gotten serious institutional attention since ketamine. Riluzole’s slower, gentler glutamate modulation is mechanistically plausible as a maintenance strategy. But the evidence is phase 2 at best, effect sizes are modest, and it’s competing for attention with compounds that are more potent and more exciting to funders.

What this compound does reliably is serve as a reference standard. Any lab working on excitotoxicity, ALS pathomechanisms, or glutamate-dependent neurodegeneration reaches for riluzole as a comparator. That keeps it in the library. But investigators looking for frontier signal should look elsewhere. The psychiatric angle is worth watching, not betting your next grant on yet.

Novelty

28

Mechanism promise

45

In-category differentiation

40

Evidence quality

70

Translational signal

60

Research bench value

65

Rationale Riluzole scores well on evidence and translational signal (FDA-approved 1995, replicated trials, confirmed human effect in ALS) but novelty is low for a thirty-year-old compound and differentiation has eroded as newer glutamate modulators emerged. Bench value keeps the overall from falling further because it remains the reference probe for presynaptic glutamate release inhibition in excitotoxicity models.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

Glutamate release inhibitor / sodium channel blocker

A benzothiazole glutamate release inhibitor with sodium channel block; the first FDA-approved drug for amyotrophic lateral sclerosis.

Abstract

Riluzole (6-(trifluoromethoxy)-1,3-benzothiazol-2-amine; CAS 1744-22-5; molecular formula C8H5F3N2OS; molecular weight 234.20) is a benzothiazole compound developed at Rhone-Poulenc and approved by the FDA in 1995 (Rilutek) for amyotrophic lateral sclerosis. The compound was the first ALS-approved drug and remained the only one until edaravone in 2017. Mechanism is multifactorial: state-dependent voltage-gated sodium channel inhibition (reducing glutamate release from presynaptic terminals), AMPA and kainate receptor antagonism (postsynaptic glutamate effect), and modest GABA-A potentiation. The combined glutamate-reducing activity addresses the excitotoxicity hypothesis of ALS pathogenesis. Plasma half-life is approximately 12 hours; metabolism is via CYP1A2. The clinical effect in ALS is modest (median survival extension approximately 2 to 3 months) but consistent across trials. Off-label use in major depressive disorder (where ketamine’s NMDA mechanism inspired interest in glutamate modulators), generalized anxiety disorder, and OCD has been investigated. Used as the canonical glutamate release inhibitor in research.

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May 9, 2026
Trenbolone

Plain-language summaryIntrigue 55 / 100

Trenbolone is a 19-nortestosterone derivative with an extra 11-dehydro double bond, originally approved as a cattle growth implant (Finaplix). It is one of the most potent anabolic steroids ever made: it binds the androgen receptor with affinity comparable to testosterone but with greater intrinsic activity, the 19-nor structure prevents aromatization to estrogen, and the 11-dehydro modification blocks the 5-alpha-reduction step that normally limits AR engagement. The combination produces dramatic anabolic effects paired with an unusually rough side-effect profile: paradoxical gynecomastia (via progesterone receptor activation), drenching night sweats, insomnia, anxiety, and putative kidney stress. Schedule III. Used as the canonical high-potency AAS reference in research. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundResearch workhorse

37/100

High-potency AAS reference probe with mature pharmacology and no active clinical development story

Look, trenbolone is one of those compounds where the chemistry is genuinely interesting and the research utility is real, but you have to be honest about what era of research this thing lives in. The 19-nor scaffold, the 11-dehydro double bond that blocks 5-alpha-reduction, the preserved aromatization resistance, the high AR affinity (Ki around 0.5 nM with strong intrinsic activity) plus meaningful progesterone receptor engagement. Structurally, thats a sophisticated profile. The paradoxical gynecomastia pathway via PR rather than via estrogen conversion is actually one of the more pharmacologically interesting features of the compound, and its been a useful case study in how non-genomic and receptor-crosstalk effects complicate the simple androgen narrative.

But the literature on trenbolone is mature in the worst way for this rubric. The bulk of it is veterinary (Finaplix cattle implant, growth promotion endpoints), forensic (WADA metabolite mapping, urine detection windows), or abuse-monitoring (adverse effect cataloguing from non-medical human use). There is no active clinical development program. Nobody is running a phase 1. The safety signal, the pharmacokinetics across the acetate and enanthate ester forms, the receptor binding constants. these are known quantities. You are not going to discover something new about trenbolone’s mechanism in 2026 that hasn’t already been characterized.

Where we think it earns its place in the library is specifically as a reference AAS for bench work. If your program involves AR pharmacology, comparing intrinsic activity hierarchies across the AAS class, or dissecting how progestogenic activity in an AAS modulates downstream androgenic signaling, trenbolone is the correct tool for the potency ceiling end of that comparison set. The structural constraints are actually useful in controlled assays because you eliminate the confounds from aromatization and 5-alpha-reduction pathways that complicate testosterone-based experiments. That probe value is real and specific.

What we don’t like: no human therapeutic signal, no active mechanistic frontier, Schedule III access hurdles in the US, and a research conversation thats largely closed rather than opening. The translational story runs in one direction. cattle and forensic labs. For a bench scientist building a new program in 2026, this isn’t where you start. For a scientist who needs a high-affinity AR/PR reference compound with well-defined pharmacokinetics to anchor a comparison study, it’s genuinely useful. That’s the honest framing and it produces a score in the high 30s, not something higher.

Novelty

20

Mechanism promise

30

In-category differentiation

45

Evidence quality

50

Translational signal

35

Research bench value

55

Rationale Trenbolone scores low on novelty and translational signal because the compound is decades old, the pharmacology is exhaustively characterized, and the human-relevant literature is almost entirely forensic or abuse-monitoring in nature. Bench value rescues it modestly as a high-affinity reference AAS for AR/PR crosstalk studies, but the Schedule III cap never binds because the calculated score sits comfortably below 75.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

19-nor 11-dehydro AAS (high-potency)

A 19-nortestosterone-derived 11-dehydro AAS; one of the most potent AAS used in cattle (Finaplix) and diverted to non-medical use.

Abstract

Trenbolone (17-beta-hydroxyestra-4,9,11-trien-3-one; CAS 10161-33-8; molecular formula C18H22O2; molecular weight 270.37) is a 19-nortestosterone-derived 11-dehydro AAS approved for veterinary use as growth-promoting cattle implant (Finaplix). The compound is among the highest-potency AAS at the androgen receptor (Ki approximately 0.5 nM, comparable to testosterone with greater intrinsic activity); the 19-nor structure prevents aromatization to estrogen, and the 11-dehydro double bond prevents 5-alpha-reduction to a more potent metabolite (the AR-active form is trenbolone itself). The AR potency combined with progesterone receptor activity produces pronounced anabolic effects with significant adverse profile: gynecomastia (paradoxical, via progestogenic activity), dramatic sweating, sleep disturbance, anxiety, and putative kidney stress. Plasma half-life of native trenbolone is short (hours); the acetate, enanthate, and hexahydrobenzylcarbonate ester forms used non-medically range from days to weeks. Schedule III in the US. Used as a high-potency reference AAS in research.

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May 9, 2026

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