No. 038 · Longevity & Immune · Longevity Peptide
SS-31
Also known as: ElamipretideForzinityMTP-131Bendavia
- FDA approved 2025
- WADA — not listed
2D structure from PubChem CID 11764719 (Elamipretide), matched by molecular formula. Hydrogens on carbon are implied.
- Nonpolar 1
- Positive charge 1
- Modified / non-standard 2
Each dot is a residue placed around the ring from N- to C-terminus; its distance from the centre reflects its chemistry.
Quick answers
- What is SS-31?
- A mitochondria-targeted tetrapeptide (elamipretide, brand Forzinity) that binds cardiolipin in the inner mitochondrial membrane.
- How strong is the evidence for SS-31?
- Tier S (approved) on the peptidemeta evidence scale. FDA granted accelerated approval in September 2025 (Forzinity) to improve muscle strength in Barth syndrome. Continued approval depends on a confirmatory randomized trial.
- Is SS-31 FDA-approved?
- Yes. The FDA approved SS-31 (Forzinity) in 2025. Accelerated approval to improve muscle strength in adults and children with Barth syndrome who weigh at least 30 kg.
- Is SS-31 banned in sport?
- No. SS-31 is not on the World Anti-Doping Agency Prohibited List.
- How does SS-31 work?
- SS-31 (Elamipretide) is a cell-permeable aromatic-cationic tetrapeptide (D-Arg-Dmt-Lys-Phe-NH2) that concentrates 1000-fold in the inner mitochondrial membrane. It binds cardiolipin, stabilizing its interaction with cytochrome c and restoring electron transport chain efficiency.
- What is known about the safety of SS-31?
- FDA-approved (Forzinity, accelerated approval 2025) for Barth syndrome; continued approval depends on a confirmatory randomized trial. Per the FDA label, the most common adverse reactions are injection site reactions.
Last reviewed · editorial policy · markdown
Evidence
- D In vitro
- C Animal
- B Human pilot
- A RCT
- S Approved
TIER S — Approved by the FDA or EMA for at least one indication.
FDA granted accelerated approval in September 2025 (Forzinity) to improve muscle strength in Barth syndrome. Continued approval depends on a confirmatory randomized trial.
Tiers rate the strength of published evidence — not effectiveness, safety, or a recommendation.
At a glance
- Residues
- 4 amino acids, N→C
- Molecular weight
- 639.8 Da
- Formula
- C32H49N9O5
- Routes studied
- Subcutaneous, Intramuscular Routes used in published research
- FDA
- Approved (2025) Forzinity Accelerated approval to improve muscle strength in adults and children with Barth syndrome who weigh at least 30 kg.
- WADA
- Not on the Prohibited List
Sequence
Note Dmt = 2′,6′-dimethyl-L-tyrosine; N-terminal D-arginine; C-terminal phenylalaninamide. Marketed as the hydrochloride salt.
Overview
A mitochondria-targeted tetrapeptide (elamipretide, brand Forzinity) that binds cardiolipin in the inner mitochondrial membrane. FDA granted it accelerated approval in September 2025 to improve muscle strength in Barth syndrome.
Research status FDA accelerated approval (Forzinity, 2025) for Barth syndrome based on the TAZPOWER trial and its open-label extension; phase 3 MMPOWER-3 in primary mitochondrial myopathy missed its primary endpoints
Mechanism
SS-31 (Elamipretide) is a cell-permeable aromatic-cationic tetrapeptide (D-Arg-Dmt-Lys-Phe-NH2) that concentrates 1000-fold in the inner mitochondrial membrane. It binds cardiolipin, stabilizing its interaction with cytochrome c and restoring electron transport chain efficiency. This reduces electron leak and reactive oxygen species production at the source.
Effects reported in research
Reported outcomes, not promises. Some come from controlled human trials; others may be from smaller or preclinical studies — check the studies below.
- Restored mitochondrial electron transport
- Reduced reactive oxygen species production
- Improved cardiac function in heart failure
- Protected against age-related mitochondrial decline
Safety & unknowns
FDA-approved (Forzinity, accelerated approval 2025) for Barth syndrome; continued approval depends on a confirmatory randomized trial. Per the FDA label, the most common adverse reactions are injection site reactions. Use outside Barth syndrome is investigational.
Unknowns. Trial safety data apply to the populations, formulations and conditions studied.
Informational only — not medical advice. peptidemeta publishes no dosing, protocols, or sourcing. Talk to a qualified clinician about any treatment decision.
Studies [2]
- Clinical trial 2024
Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER
Open-label extension of the TAZPOWER trial reporting sustained tolerability and improvements in functional assessments and cardiac function with elamipretide in Barth syndrome over 168 weeks.
- Clinical trial 2023
Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial
Phase 3 randomized placebo-controlled trial in primary mitochondrial myopathy in which elamipretide did not improve the primary endpoints (6-minute walk distance and fatigue scores) versus placebo.
Status sources
Sources behind the tier, regulatory status, sequence and dates on this page.
- FDA approval letter, NDA 215244 (Forzinity), 19 Sep 2025 accessdata.fda.gov
- Forzinity prescribing information (FDA label) accessdata.fda.gov
- PubChem CID 11764719 (elamipretide) pubchem.ncbi.nlm.nih.gov
- WADA 2026 Prohibited List (not named; S0 does not apply to an approved drug) wada-ama.org
Cite this entry
peptidemeta. (2026). SS-31. In peptidemeta: The peptide library, ranked by evidence. Retrieved November 8, 2026, from https://peptidemeta.com/p/ss-31/
@misc{peptidemeta-ss-31,
title = {SS-31},
author = {{peptidemeta}},
year = {2026},
howpublished = {\url{https://peptidemeta.com/p/ss-31/}},
note = {Accessed 2026-11-08}
} Accessed date reflects when you opened this page. Cite primary studies for scientific claims.