KDC-MN-012 – Kodiac biolabs

Plain-language summaryIntrigue 88 / 100

SS-31, also called elamipretide, is a four-amino-acid peptide that selectively targets the inner mitochondrial membrane. It binds cardiolipin (a unique mitochondrial lipid) and stabilizes the mitochondrial membrane during stress, with research interest in heart failure, kidney disease, and aging. Stocked in the Kodiac catalog as a research-only powder for laboratory work; not a medicine, not for human consumption.

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 Kodiac editorial, not peer-reviewed.

Our opinion on this compoundNovel, promising

63/100

Cardiolipin-targeted mitochondrial probe with real Phase 2/3 clinical data, mixed outcomes, and strong bench utility in mitochondrial disease models

Look, SS-31 is one of those compounds where the mechanism is genuinely beautiful and the clinical story is genuinely complicated. Hazel Szeto’s group at Cornell spent years establishing that cardiolipin, the signature phospholipid of the inner mitochondrial membrane, is a target you can actually modulate with a synthetic tetrapeptide. That insight wasn’t obvious when the SS series was first described. The Dmt substitution over tyrosine in SS-02 wasn’t cosmetic either: it’s what gives SS-31 the stability and binding affinity that makes it useful at all in biological systems, and mass spec distinguishes the two readily enough that adulteration is a tractable quality concern rather than an invisible one.

The mechanistic story is compelling at the bench level. Cardiolipin doesn’t just sit there in the inner membrane looking pretty; it scaffolds the supercomplexes of the electron transport chain, particularly the Complex I/III/IV associations. When you perturb that environment through oxidative stress, the supercomplexes destabilize, electron flow becomes leaky, ROS output increases, and you get the downstream cascade that defines mitochondrial dysfunction in aging and ischemic disease. SS-31 interrupts that cascade upstream, at the lipid level, rather than scavenging ROS after the fact. Thats mechanistically more interesting than antioxidant supplementation and it explains why the compound has stayed in serious investigator hands even as its clinical arc has been uneven.

The clinical translation is where the story gets messier. Stealth BioTherapeutics ran a genuine program: Phase 2 work in cardiac ischemia, heart failure with preserved ejection fraction, Barth syndrome, primary mitochondrial myopathies, and age-related macular degeneration. The AMD program hit a real wall; the FDA issued a complete response letter for geographic atrophy requesting additional data, and that’s a setback that can’t be soft-pedaled. But the Barth syndrome and primary mitochondrial myopathy results are legitimately interesting. Barth is a rare cardiolipin remodeling disorder where elamipretide’s mechanism isn’t just plausible, its almost mechanistically required. Phase 2 functional improvements in that population were meaningful. Primary mitochondrial myopathy data has been more modest but directionally real.

What we like: SS-31 remains a useful probe for cardiolipin biology at the bench. If you’re running oxidative stress models, aging models, or ischemia-reperfusion work, having SS-31 as a chemical tool lets you ask specifically whether cardiolipin stabilization is part of whatever protective phenotype you’re seeing. Thats real probe value that doesn’t depend on the clinical outcomes resolving cleanly.

What we don’t like: this peptide has been around since the early 2000s, the core mechanism literature is mature, and the Phase 3 record is mixed at best. SS-31 isn’t breaking new ground anymore; it’s validating or failing to validate an established idea in new disease contexts. For an investigator building a new research program from scratch, SS-31 is a well-characterized tool in an active space, not a frontier target. Solid mid-tier compound, genuinely important in its niche, not the first thing we’d prioritize for an undirected lab.

Novelty: 55
Mechanism promise: 72
In-category differentiation: 65
Evidence quality: 60
Translational signal: 57
Research bench value: 68

Rationale SS-31 earns its mid-tier placement on genuine mechanistic elegance (cardiolipin supercomplex stabilization upstream of ROS) and a real multi-indication clinical program through Stealth BioTherapeutics, but the compound’s 20-year vintage, an FDA complete response letter for geographic atrophy, and mixed Phase 3 signals pull novelty and translational scores down; bench value stays solid because it remains the reference peptide probe for cardiolipin biology and has no real structural analogue for that specific question.

Synthetic tetrapeptide mitochondrial-targeting cardiolipin-binding peptide

A 4-amino-acid mitochondrial-targeting peptide developed at Cornell University, characterized for binding to cardiolipin in the inner mitochondrial membrane and protecting mitochondrial function in oxidative stress.

Abstract

SS-31 (sequence D-Arg-Dmt-Lys-Phe-NH2, also known as elamipretide, Bendavia, MTP-131; CAS 736992-21-5; molecular formula C32H49N9O5; molecular weight 639.79) is a synthetic tetrapeptide developed in the laboratory of Hazel Szeto at Cornell University Medical College beginning in the early 2000s. The peptide is the most extensively characterized member of the Szeto-Schiller (SS) series of mitochondrial-targeting tetrapeptides. The biological mechanism is binding to cardiolipin in the inner mitochondrial membrane, which protects the membrane lipid environment from peroxidation, stabilizes the supercomplexes of the electron transport chain, and improves mitochondrial efficiency in conditions of oxidative stress or mitochondrial dysfunction. The compound is the active pharmaceutical ingredient in elamipretide (Bendavia), which has been advanced through Phase 2 and Phase 3 clinical trials by Stealth BioTherapeutics for primary mitochondrial myopathies, age-related macular degeneration (dry AMD with geographic atrophy), Barth syndrome, and other mitochondrial dysfunction indications. The clinical record is mixed; the most-promising results have come in Barth syndrome and primary mitochondrial myopathy. The compound is not approved by any regulatory authority for human or veterinary use as of this revision; recent FDA review in geographic atrophy resulted in a complete response letter requesting additional data. The Kodiac biolabs lot of record is SW260307, manufactured 7 March 2026 by Xian Sowu Biotech, with a vendor COA assay of 99.62 percent and a supplementary HPLC area-percent of 99.18 percent at 220 nm; both documents are archived on the lab results page.

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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.

Tag: KDC-MN-012

SS-31

Abstract

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