Cardiolipin Stabilization & Mitochondrial Cristae Restoration
SS-31 (Elamipretide) — Mitochondria-Targeted Tetrapeptide
Last reviewed: August 2026
SS-31 (Elamipretide) is a 4-amino-acid peptide that targets cardiolipin in the inner mitochondrial membrane. Phase II trials showed encouraging signals, but the pivotal Phase 3 MMPOWER-HF trial (n=360, 2023) did not meet its primary endpoint. Efficacy is not demonstrated in humans. Anti-aging and longevity effects are preclinical only.
SS-31 concentrates 1,000-fold in the inner mitochondrial membrane, stabilizing cardiolipin and the electron transport chain complexes that produce ATP. This reduces ROS production, improves energy output, and protects against mitochondrial dysfunction.
Mitochondrial dysfunction is a hallmark of aging and a driver of heart failure and neurodegeneration. SS-31 concentrates at the exact site of ROS generation — a precision that conventional antioxidants lack.
SS-31 is a mitochondria-targeted tetrapeptide with a well-characterized mechanism and the most advanced clinical program of any mitochondria-targeted peptide. However, the Phase 3 MMPOWER-HF trial failed its primary endpoint. Human efficacy is not demonstrated. Anti-aging effects are preclinical only.
SS-31 (also known as Elamipretide or MTP-131) is a tetrapeptide that selectively concentrates in the inner mitochondrial membrane, where it binds cardiolipin — a phospholipid essential for electron transport chain function. The proposed mechanism involves stabilizing cardiolipin and restoring cristae architecture. Phase II trials in heart failure showed encouraging signals, but the pivotal Phase 3 MMPOWER-HF trial (n=360, 2023) did not meet its primary endpoint. Efficacy is not demonstrated in humans. Anti-aging and longevity effects are preclinical only.
SS-31 is a 4-amino-acid tetrapeptide with an alternating aromatic-cationic motif (D-Arg-2',6'-Dmt-Lys-Phe-NH2). The dimethyltyrosine (Dmt) residue provides antioxidant activity, while the cationic residues (D-Arg, Lys) drive electrostatic concentration in the inner mitochondrial membrane, achieving 1,000-fold enrichment relative to cytoplasm.
SS-31 restores mitochondrial function by stabilizing cardiolipin in the inner mitochondrial membrane, improving ATP production efficiency and reducing damaging free radical leakage.
SS-31 concentrates in the inner mitochondrial membrane via electrostatic interactions, where it binds cardiolipin — a phospholipid that anchors electron transport chain complexes. By stabilizing cardiolipin, SS-31 maintains optimal cristae architecture and ETC complex conformation, improving ATP synthesis efficiency and reducing electron leak (and consequent ROS generation).
Binds cardiolipin in the inner mitochondrial membrane, stabilizing cristae structure and maintaining optimal conformation of electron transport chain complexes for efficient ATP synthesis.
Reduces mitochondrial superoxide and hydrogen peroxide production by preventing electron leak from the electron transport chain.
Protects against ischemia-reperfusion injury by maintaining mitochondrial membrane potential and preventing mPTP opening during reperfusion.
Each outcome rated by the highest level of evidence available. Tiers follow our 5-tier methodology.
Study counts reflect peer-reviewed publications in the evidence database below. "Theoretical" outcomes have mechanistic rationale only. Learn about our evidence tiers →
Peer-reviewed literature supporting the research profile of SS-31
The following peer-reviewed studies form the primary evidence base for SS-31's research profile. All references are sourced from PubMed, NCBI, and peer-reviewed scientific journals. Published research is available through PubMed, NCBI, and peer-reviewed biomedical journals.
Szeto HH. First-in-class cardiolipin-protective compound as a therapeutic agent to restore mitochondrial bioenergetics. British Journal of Pharmacology. 2014.PMID: 24117165
SS-31 (Elamipretide) protects cardiolipin and restores mitochondrial cristae structure and ATP production.
Chatfield KC, et al. Elamipretide improves mitochondrial function in the failing human heart. JACC: Basic to Translational Science. 2019.PMID: 31061916
SS-31 improved mitochondrial respiration in human failing heart tissue ex vivo.
Daubert MA, et al. Novel Mitochondria-Targeting Peptide in Heart Failure Treatment: A Randomized, Placebo-Controlled Trial of Elamipretide. Circulation: Heart Failure. 2017.PMID: 29217757
Phase II trial: SS-31 (elamipretide) improved cardiac function and exercise capacity in heart failure patients.
Longevity Research
Purgo Labs list price, read 12 Sep 2026 · per-lot COA on the vendor page
Purgo Labs does not list SS-31 (checked 26 Sep 2026)
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Where to buy SS-31
Purgo Labs does not list this compound — every scored vendor that does, with dated prices
Extensive human trial data for the pharmaceutical form (elamipretide); research-grade SS-31 is not that product
SS-31 is the research name for elamipretide, a mitochondria-targeting tetrapeptide that Stealth BioTherapeutics has taken through multiple randomised trials in heart failure, primary mitochondrial myopathy and Barth syndrome. Its adverse-effect profile is therefore unusually well characterised for a compound sold by research vendors: injection-site reactions dominate. The efficacy record is mixed, which matters when weighing any risk.
Research-use information only. Research-grade SS-31 is not an approved medicine; where trial or label figures appear below they belong to the pharmaceutical product studied, not to any research vial. This section does not give dosing or medical advice.
Every rate carries its source. Where no source exists, no rate is printed.
| Effect | Rate (sourced) | Detail | Source |
|---|---|---|---|
| Injection-site reactions (erythema, pain, pruritus) | not quantified | The most frequent adverse event across subcutaneous elamipretide trials; generally mild and reported at high frequency in daily-injection studies. | Daubert et al. 2017 (PROGRESS-HF); Stealth BioTherapeutics trial reports |
| Serious adverse events | not quantified | No consistent drug-related serious adverse-event signal has been reported across the published trials. | Daubert et al. 2017; Szeto 2014 (review) |
Regulatory status: Elamipretide received FDA accelerated approval for Barth syndrome in 2025 (marketed as Forzinity); it is not approved for any other indication. Research-grade SS-31 is not the approved product.
Everything above describes SS-31 the molecule. The risk specific to a research vial is different: it may not contain SS-31 at the labelled amount, and it may contain what the synthesis left behind. Identity (mass spectrometry), purity (HPLC), measured net content and an endotoxin result are the four lines on a certificate that bear on adverse effects, and only a certificate you can check at the laboratory tells you any of them. This is what we have verified for SS-31 so far.
20 of the 105 vendors on our scoreboard list SS-31 with a price we read on the product page (23 Sep 2026–1 Nov 2026). Of those, 20 name their testing laboratory, 17 publish certificates that resolve on the lab's own site, and 19 publish measured milligrams against the label. The full ranking, with every dated price, is on Best SS-31 Vendors.
| Vendor | Rubric | Lab named | Price read |
|---|---|---|---|
| MyPurePeptidepartner | 10/10 | Janoshik Analytical | $80.00 · 50mg · 1 Nov 2026 |
| Oneday Compoundspartner | 10/10 | ILS Laboratories (San Diego, CA) | $20.99 · 10mg · 29 Oct 2026 |
| Peptide Giantspartner | 10/10 | Janoshik Analytical · Vanguard Laboratory | $49.99 · 10mg · 1 Nov 2026 |
| Premier Bio Labs | 10/10 | ILS Laboratories + Freedom Diagnostics | $55.99 · 10mg · 1 Nov 2026 |
| ezPepspartner | 9/10 | ILS Laboratories (also Kovera Labs, Freedom Diagnostics, Horizon Analytical) | $129.99 · 50mg · 31 Oct 2026 |
Top 5 by rubric score; 15 more on the ranking page.
None yet for SS-31 specifically. The COA library holds the certificates we have read for each vendor on other compounds, which is the next best signal of how that vendor documents a lot.
In the published elamipretide trials, injection-site reactions — redness, pain, itching — were by far the most common, and were usually mild. No consistent serious adverse-event signal has been reported. Those data come from the pharmaceutical product given under trial conditions, not from research vials.
Elamipretide has a narrow 2025 FDA accelerated approval for Barth syndrome, a rare mitochondrial disease. It is not approved for heart failure, mitochondrial myopathy, ageing or performance, and research-grade SS-31 is not the approved product.
Side-effect section last reviewed 2026-09-13. Moved from the standalone side-effects page on 10 October 2026; text unchanged.
SS-31 (Elamipretide, MTP-131) is legal to purchase and possess in the United States as a research chemical. It is not a controlled substance under the DEA Controlled Substances Act. It has been studied in Phase II clinical trials for heart failure and mitochondrial myopathy but is not FDA-approved for human use.
| Jurisdiction | Status as stated |
|---|---|
| United States | Not a controlled substance. Legal to purchase as a research chemical. Not FDA-approved for human use. Has been studied in Phase II clinical trials. |
| Canada | Not a scheduled substance. Legal for research purposes. Not approved by Health Canada for human use. |
| United Kingdom | Not a controlled drug under the Misuse of Drugs Act. Legal for research purposes. |
| Australia | Not listed as a scheduled substance by the TGA. Legal for research purposes. |
| European Union | Not a controlled substance in most EU member states. Legal for research purposes. |
| WADA / Sports | SS-31 is not explicitly listed on the WADA Prohibited List. However, athletes should consult their governing body before use. |
Statements above are as our legal-status page for SS-31 stated them in 2025; they were moved here on 10 October 2026 and were not re-verified in the move. Regulations change. This is general information, not legal advice; check the current position with your own jurisdiction's regulator before relying on it.
No. SS-31 (Elamipretide) is not listed as a controlled substance under the US DEA Controlled Substances Act. It is not scheduled at the federal level in the United States.
Yes. SS-31 can be legally purchased as a research chemical in the United States. It should not be sold or purchased for human consumption.
Yes. SS-31 (Elamipretide) has been studied in Phase II clinical trials for conditions including heart failure with preserved ejection fraction (HFpEF) and mitochondrial myopathy, though it has not received FDA approval.
SS-31 is not explicitly listed on the WADA Prohibited List. Athletes subject to anti-doping rules should consult their governing body before use.
SS-31 is not listed as a scheduled substance by the TGA in Australia. It is legal for research purposes but regulations can change — always verify current status before purchasing.
SS-31 (elamipretide) had encouraging Phase 2 cardiac data, but the pivotal Phase 3 trial (MMPOWER-HF, n=360) failed its primary endpoint in 2023 — no significant improvement in 6-minute walk distance vs placebo. The Barth syndrome program continues. Anti-aging, exercise, and longevity claims are preclinical only. Present the Phase 3 failure honestly.
Purgo Labs does not currently list SS-31. The ranking below covers every scored vendor that does, with dated product-page prices.
