RESEARCH MONOGRAPH · KDC-MN-012

SS-31

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 2 min read

Our opinion on this compound

73/100

Mitochondrial-targeting peptide with serious clinical pipeline. Different category of seriousness from most peptides we cover

SS-31 (elamipretide, also called Bendavia, also MTP-131) is a fundamentally different kind of compound from most of what circulates in the peptide research space. This is a clinical-stage drug developed by Hazel Szeto at Cornell, currently in late-phase trials for primary mitochondrial myopathy and Barth syndrome through Stealth Biotherapeutics. The biology is taken seriously by serious cardiology and mitochondrial-disease groups.

The tetrapeptide sequence (D-Arg-Tmt-Lys-Phe-NH2) is engineered to do one specific thing. Penetrate cell membranes despite being hydrophilic, accumulate in mitochondria via electrostatic attraction to the negatively charged inner membrane, and bind cardiolipin at the inner mitochondrial membrane. That cardiolipin binding is the mechanism. Cardiolipin organizes the supercomplexes of the electron transport chain, particularly Complex IV, and SS-31 stabilizes that organization under oxidative or aging stress.

The Szeto and Hoppel papers laying out this mechanism are some of the most elegant mitochondrial pharmacology of the last twenty years. The compound increases ATP production efficiency, reduces mitochondrial ROS generation, and protects against ischemia-reperfusion injury in multiple organ systems. Heart failure with preserved ejection fraction (HFpEF) was a major clinical target, with mixed results in the PROGRESS-HF and MMPOWER trials. The primary mitochondrial myopathy program looks more promising.

Whats interesting is how the cellular pharmacology differs from antioxidants generally. SS-31 isn't a free-radical scavenger per se; it modulates electron transport chain organization to prevent excess ROS formation upstream. That mechanistic distinction matters because most antioxidant interventions in clinical mitochondrial medicine have failed, while SS-31's structural-stabilization angle is fresh.

Sourcing is more complicated than typical research peptides. The Dmt residue (2,6-dimethyltyrosine) is non-standard and not every vendor synthesizes it correctly. The D-arginine and amidated C-terminus also require careful synthesis. Vendor variability is real, watch the COA closely and prefer suppliers with mass-spec verification of the exact stereochemistry and amidation status.

What we don't love is the recent uptake in non-clinical research markets where the QC story is much weaker than the clinical-grade material Stealth produces. Buy carefully.

Genuinely promising, real clinical pipeline, real mechanism, take this category seriously.

Evidence: 75
Mechanism: 85
Reliability: 75
Safety: 78
Sourcing: 65
Value: 50
Signal: 75
Staying power: 80

Plain-language summary Intrigue 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.

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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The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, reported research dose ranges, sourcing and quality verification, reconstitution and handling, stack interaction considerations, and a curated reference list. Available as a research-use-only PDF download.

KDC-MN-012

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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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.

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SS-31

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