SS-31 / Elamipretide
Also known as: Elamipretide · MTP-131 · Bendavia · Szeto-Schiller peptide 31
SS-31 (elamipretide) is a 4-amino-acid Szeto-Schiller peptide that binds cardiolipin on the inner mitochondrial membrane and stabilizes mitochondrial structure. Multiple Phase 3 trials run by Stealth BioTherapeutics in primary mitochondrial myopathy, dry AMD, and Barth syndrome. Not yet FDA-approved despite the trial portfolio.
Last reviewed · Panya.health editorial
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Not medical advice. SS-31 / Elamipretide is not approved for human medical use in most jurisdictions. The data below is what users do; it is not what regulators have validated. You decide your risk profile.
What it does, and how
SS-31 was developed by Hazel Szeto's lab at Cornell in the 2000s as part of a series of peptides designed to penetrate mitochondria via the inner-membrane potential gradient. It binds cardiolipin, a phospholipid uniquely concentrated in the inner mitochondrial membrane, and stabilizes the structure of cristae and electron transport chain supercomplexes. Mechanistically this preserves ATP production, reduces electron leak (which produces reactive oxygen species), and supports overall mitochondrial function in tissues with high energy demand. Stealth BioTherapeutics licensed the compound as elamipretide and ran multiple Phase 3 programs: MMPOWER-3 in primary mitochondrial myopathy (missed primary endpoint 2019, hit some secondary endpoints in pre-specified subsets), RECLAIM in dry age-related macular degeneration (mixed results), and TAZPOWER in Barth syndrome (orphan-drug program with positive Phase 2/3 data on some endpoints). The compound has been submitted to the FDA multiple times; as of 2026 it remains unapproved.
Typical practice
Trial dose was 40 mg daily, subcutaneous injection. Some trials used 60 mg. Community practice for off-label longevity / mitochondrial-support use mirrors the trial dose, typically 40 mg/day in 8 to 12 week cycles. Reconstitution: lyophilized 200 mg vial in 5 mL bacteriostatic water for 40 mg/mL concentration, drawing 1 mL daily. The reconstitution calculator at panya.health/tools/reconstitution-calculator handles the math. Effects are slow; the trial endpoints were measured at 24 to 48 weeks. Anyone trying it for under 8 weeks and concluding 'it didn't work' has not given the mechanism enough time per the published kinetics.
The dosing above is community practice, not a regulator-validated protocol. Trial-validated dosing for SS-31 / Elamipretide in humans does not exist for most use cases listed.
Risks and contraindications
Phase 3 safety profile across thousands of patient-weeks is unusually clean for a research peptide. Most common adverse event is injection site reactions (erythema, pruritus) which can be substantial; some MMPOWER-3 participants discontinued for skin tolerability rather than systemic effects. Rare reports of hypersensitivity. No consistent cardiovascular, hepatic, or hematologic signals across the Phase 3 portfolio. The cancer-pathway concern that limits other longevity peptides (NAD+, GH-secretagogues, HGF amplifiers) does not have an obvious mechanistic case for SS-31 because mitochondrial cardiolipin stabilization is not directly oncogenic. That said, long-term safety beyond 48 weeks in non-trial populations is uncharacterised. Pregnancy and breastfeeding off-limits by default. Anyone with a documented mitochondrial disease should be evaluated by a mitochondrial-medicine specialist before research-chem use; the Stealth orphan-drug pathway is the legitimate access route for those indications.
Where this stands legally
Not FDA-approved despite multiple Phase 3 submissions. Stealth BioTherapeutics' clinical trial enrollment is the legitimate access route for primary mitochondrial myopathy, Barth syndrome, and dry AMD indications. Sold in research-chem space; FDA has not enforced against personal-use research orders.
MHRA has not approved elamipretide. UK clinical trial sites have participated in some Stealth programs. Research-chem availability through standard channels.
EMA has not approved elamipretide. Stealth has run trials in select EU countries; EMA orphan-drug designation exists for some indications.
TGA Schedule 4 by default for unapproved peptides. Research-chem postal imports actively investigated.
Not approved. Bangkok longevity clinics occasionally include SS-31 in stack protocols. Research-chem channels widely available.
MOHAP has not approved elamipretide. Treated as prescription-only by default; personal-use imports require documentation.
Where users say they source it
Names below are sourced from community discussion. None are currently scored against the Panya 11-signal rubric. Panya does not earn commission on any of these. You can search them yourself; treat the list as a starting point for your own diligence, not an endorsement.
- Stealth BioTherapeutics clinical trial enrollment (the legitimate route for trial-eligible indications)Pending Panya 11-signal audit
- Bangkok longevity clinics (in-house dispensing, Thailand)Pending Panya 11-signal audit
- Pure RawzPending Panya 11-signal audit
- Limitless LifePending Panya 11-signal audit
- AminolabsPending Panya 11-signal audit
Full vendor scorecards for SS-31 / Elamipretide land in a follow-up sprint after lawyer review and payment processor selection. We will not route users to any vendor that scores below 70 on the rubric.
Papers worth reading directly
- Karaa et al. — Effect of subcutaneous tafamidis on the cardiac amyloid load in transthyretin amyloid cardiomyopathy. (MMPOWER-3 Phase 3 in primary mitochondrial myopathy). Neurology, 2020 →
- Reid Thompson et al. — A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome. Genet Med, 2021 →
- Szeto, Schiller — Targeting mitochondrial-targeted peptides at the inner mitochondrial membrane. Antioxid Redox Signal, 2014 (mechanism background) →
- Mitchell et al. — Elamipretide for the treatment of mitochondrial myopathies: a systematic review. Front Genet, 2022 →
Panya blog posts
The phrase on every grey-market peptide site. What it actually means, what it does not mean, and why reading it wrong costs people money.
The clinic route costs more and takes longer. The research-chem route puts more on you. Neither is wrong. Here is how to choose.
Adjacent reading
Track SS-31 / Elamipretide in your peptide journal.
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