SS-31 (Elamipretide, MTP-131, Bendavia)
Published · Researched 2026-09-21
Overview
SS-31 (Elamipretide; also coded MTP-131, Bendavia) is a synthetic mitochondria-targeting tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH2, where Dmt is 2',6'-dimethyltyrosine. Developed by Stealth BioTherapeutics, it concentrates in the inner mitochondrial membrane by binding cardiolipin, stabilizing cristae structure and scavenging reactive oxygen species at the membrane source. It is the most clinically pedigreed peptide in this category: on 19 September 2025 the FDA granted it accelerated approval as Forzinity (elamipretide HCl) — the first-ever treatment for Barth syndrome, indicated to improve muscle strength in patients weighing at least 30 kg, and designated a first-in-class medication. Current status in 2026: FDA-approved prescription drug (Rx-only, subcutaneous) for Barth syndrome only; all other uses remain investigational, and grey-market vials are unapproved research chemicals.
Social standing
- Threads: @peptidecourses (Jun 2025) ran an educational series calling SS-31 "your mitochondrial electrician" — "binds to cardiolipin in the inner mitochondrial membrane, stabilizing energy production and reducing ROS leak — especially in the heart." @sy524771 (Aug 2026) posted a safety-observation thread: "Skin reactions after using SS-31 (Elamipripeptide) are very common. Most of them are injection site reactions (ISRs), not allergies that are really mediated by IgE," citing clinical and patent/research data on subcutaneous injection reactions. @drpaulvin (Apr 2024) listed SS-31 and MOTS-c as "two of the major anti-aging peptides" a prominent podcast failed to discuss — a marker of its insider status.
- Web/community: A 2026 Medium buyer guide (PeptidePub) did cross-vendor cart math on SS-31 + MOTS-c stacks, treating SS-31 as the premium-priced anchor (~$2.38/mg at the low end). Vendor pages (Koi, Real Peptides, 303 Peptides, Spyro) carry customer reviews; Spyro shows 8 reviews at 5.00/5 for its 10 mg vial.
- FDA approval (Sep 2025): Elamipretide received FDA accelerated approval as Forzinity for Barth syndrome — the first FDA-approved mitochondrial peptide, designated first-in-class. The event drew mainstream coverage (Reuters/PharmaLive, WebMD, BioSpace, Laafon Galaxy) and a dedicated community analysis on researchingpeptides.com. Reuters reported the approval came over the objections of nearly a dozen FDA reviewers, with a list price up to ~$800,000/year — a controversy the peptide community has discussed as a landmark moment for mitochondrial peptides.
- Recurring praise: the cardiolipin mechanism is considered the most scientifically legitimate in the longevity-peptide space; the clinical-trial pedigree (Stealth BioTherapeutics program) gives it credibility other peptides lack; discussed for energy, endurance, cardiac and muscle mitochondrial support.
- Recurring complaints/failure modes: injection-site reactions are very commonly reported (redness, itching, welts — generally ISRs rather than true allergy, per the Aug 2026 thread); high price relative to other peptides; daily or every-other-day dosing burden; short plasma half-life (~2 hours per vendor data); grey-market vials vary in quality.
Social validation
Tier 2 — strong independent evidence on two legs: Threads (educator accounts + a safety-signal thread citing clinical data) and web community (buyer guides, vendor review sections). Facebook leg is weak: the two accessible FB peptide groups returned zero posts for ss-31/elamipretide and no relevant Marketplace listings existed. What each source proves: Threads proves practitioner-level mechanism discussion and real-world adverse-event chatter (ISRs); the buyer-guide content proves active purchasing with price sensitivity.
Key specs table
| Spec | Value |
|---|---|
| Sequence | D-Arg-Dmt-Lys-Phe-NH2 (Dmt = 2',6'-dimethyltyrosine) |
| Synonyms | Elamipretide, MTP-131, Bendavia |
| CAS | 736992-21-5 (free base) |
| Molecular formula | C32H49N9O5 |
| Molecular weight | 639.8 g/mol (free base); PubChem CID 11764719 |
| Form | Lyophilized powder, typically 10 mg or 50 mg vials |
| Purity (vendor-claimed) | ≥99% HPLC, LC-MS identity, endotoxin-screened on reputable vendors |
| Half-life | ~2 hours plasma (per Sacred Peptides vendor data) |
| Storage | Lyophilized: -20 °C protected from light; reconstituted: 2–8 °C short-term |
| Developer | Stealth BioTherapeutics (investigational drug program) |
Pricing
Observed 2026-09-20. Street range for 10 mg vial: ~$48–$140 USD.
- Koi Peptides: $49.95/10 mg (22 in stock; Freedom Diagnostics COA, net 12.34 mg, reported Mar 2026)
- Real Peptides: $48.00/10 mg, USA-finished
- Lumin Peptides: $65.99/10 mg
- Spyro Peptides: $120.00/10 mg (batch tested Jul 2026)
- 303 Peptides: $126.00/10 mg (sale from $140)
- Sacred Peptides (Canada): $289 CAD/50 mg
- Nova Labs via Atlas Nutrition (South Africa): R700 ZAR/10 mg
- Double R (via 2026 buyer guide): 50 mg
$118.99 after code ($2.38/mg) - Facebook Marketplace used range: none observed (one irrelevant jeans listing matched "SS-31")
What's included / what's needed
Included: lyophilized peptide vial only. Needed: bacteriostatic/sterile water, syringes, refrigeration. Community-discussed framing (South African vendor page): 2,000–10,000 mcg daily or every other day, morning administration — presented as vendor/community material, not a recommendation.
Support reality
Vendor-dependent. Koi advertises same-day dispatch and free shipment protection; Spyro and others publish lot-matched COAs. Community emphasis is on COA verification (HPLC + LC-MS) because SS-31's price makes it a counterfeit target. No manufacturer patient support — Stealth BioTherapeutics' program is clinical-trial only.
Regulatory & safety status
Elamipretide is an FDA-approved prescription drug — with a critical scope limit. On 19 September 2025 the FDA granted accelerated approval to Forzinity (elamipretide hydrochloride, Stealth BioTherapeutics) for Barth syndrome, indicated to improve muscle strength in patients weighing at least 30 kg; the FDA called it a first-in-class medication and granted priority review plus rare pediatric disease designations (FDA announcement "FDA Grants Accelerated Approval to First Treatment for Barth Syndrome," Sep 2025, via the FDA's official govdelivery channel; corroborated by HealthDay/Drugs.com MedNews). It is Rx-only, given subcutaneously once daily; the most common side effects in clinical trials were mild-to-moderate injection-site reactions. It has also been researched for heart failure, macular degeneration, diabetic foot ulcers, and hypertension, but is only approved for Barth syndrome — every other use, including all longevity/biohacker use, is investigational and unapproved. Grey-market SS-31 vials sold online are NOT the approved drug: they are unapproved research chemicals sold "for laboratory research use only," with no FDA oversight of their purity, sterility, or content. Not EMA-approved: Stealth BioTherapeutics' own January 2026 commercial update states "There are no EMA-approved therapies for patients with BTHS."
Community verdict
SS-31 is the "serious" mitochondrial peptide — real drug-development pedigree and the clearest mechanism in the category — but that legitimacy comes with real-drug downsides: frequent injection-site reactions, premium pricing, and demanding dosing. The community treats it as the high-conviction, high-cost mitochondrial option, not a casual longevity staple.
Not medical advice. This is a research summary only; SS-31/Elamipretide is FDA-approved only as Forzinity for Barth syndrome — all other uses are investigational or grey-market.
Images
7 real images on file (img/ss-31-{hero,profile,rear,top,detail,scale,box}.jpg) — product identity verified at acquisition from vendor sources. Missing view: in-use — no genuine traceable owner-use photo found; not substituted.
Named sources
- Threads @peptidecourses — @peptidecourses (Jun 2025) ran an educational series calling SS-31 "your mitochondrial electrician" — "binds to cardiolipin in the inner mitochondrial membrane, stabilizing energy production and reducing ROS leak — especially in the heart." @sy524771 (Aug… (Jun 2025)
- @sy524771 — @peptidecourses (Jun 2025) ran an educational series calling SS-31 "your mitochondrial electrician" — "binds to cardiolipin in the inner mitochondrial membrane, stabilizing energy production and reducing ROS leak — especially in the heart." @sy524771 (Aug… (Jun 2025)
- @drpaulvin — @drpaulvin (Apr 2024) listed SS-31 and MOTS-c as "two of the major anti-aging peptides" a prominent podcast failed to discuss — a marker of its insider status. (Apr 2024)
- FDA review — Reuters reported the approval came over the objections of nearly a dozen FDA reviewers, with a list price up to ~$800,000/year — a controversy the peptide community has discussed as a landmark moment for mitochondrial peptides.
- Threads — @peptidecourses (Jun 2025) ran an educational series calling SS-31 "your mitochondrial electrician" — "binds to cardiolipin in the inner mitochondrial membrane, stabilizing energy production and reducing ROS leak — especially in the heart." @sy524771 (Aug… (Jun 2025)
- Sacred — | Half-life | ~2 hours plasma (per Sacred Peptides vendor data) |
- Atlas — - Nova Labs via Atlas Nutrition (South Africa): R700 ZAR/10 mg
Source URLs were not recorded for these references.