SoluneFit

Peptide library

Elamipretide

FDA-approved (prescription) Evidence grade A — regulator-approved with pivotal randomised trials Updated 2026-10-20

This page describes published research and public regulatory records. It is not medical advice. SoluneFit does not sell, supply, or recommend any compound. The SoluneFit app includes a private, on-device tracker for people who want a record of what they and their clinician have already decided — the app neither suggests compounds nor doses.

Also known as: SS-31, Forzinity, MTP-131, Bendavia, elamipretide hydrochloride.

Regulatory status

FDA accelerated approval 19 Sep 2025 (Forzinity, Stealth BioTherapeutics) to improve muscle strength in Barth syndrome, patients weighing at least 30 kg; based on knee-extensor strength as a surrogate endpoint, with a confirmatory randomised placebo-controlled trial required [1][2]. Prescription only; no other approved use.

What it is

Mitochondria-targeted synthetic tetrapeptide (cardiolipin binder).

A small four-amino-acid peptide that concentrates in the inner mitochondrial membrane. Approved in the US in September 2025 (as Forzinity, accelerated approval) to improve muscle strength in Barth syndrome; it failed its phase 3 trial in primary mitochondrial myopathy.

What the published research shows

Approved (accelerated) on a pivotal but very small trial: 12 patients in a randomised crossover that missed both primary endpoints, with strength gains seen only in the open-label extension; confirmatory trial still required. The 218-patient phase 3 MMPOWER-3 trial in primary mitochondrial myopathy was negative. Weakest end of grade A.

Published human studies and reports (these describe trial populations, not SoluneFit claims):

  • Barth syndrome, patients at least 30 kg (Forzinity label): Label: 40 mg subcutaneously once daily; 20 mg once daily in adults with eGFR below 30 mL/min not on dialysis.
  • Barth syndrome (TAZPOWER phase 2/3 trial, Genet Med 2021): 12 patients randomised to 40 mg/day subcutaneously or placebo for 12 weeks, 4-week washout, then crossover; neither primary endpoint (6-minute walk, symptom scale) was met. In the open-label extension (8 patients at 36 weeks) 6-minute walk improved by 95.9 m.
  • Barth syndrome (TAZPOWER 168-week open-label extension, Genet Med 2024): Long-term open-label follow-up of the same cohort on 40 mg/day; uncontrolled.
  • Primary mitochondrial myopathy (MMPOWER-3 phase 3 RCT, Neurology 2023): 218 adults randomised 1:1 to 40 mg/day subcutaneously or placebo for 24 weeks; no difference in 6-minute walk (−3.2 m, p = 0.69) or fatigue score.

Mechanism, as reported

Binds cardiolipin, a lipid of the inner mitochondrial membrane, and is reported to improve mitochondrial structure and function. Its two breakdown products are inactive.

Practical record

  • Studied routes: subcutaneous.
  • Typical supply: Forzinity: 280 mg/3.5 mL (80 mg/mL) single-patient-use vials, carton of four (Rx). Also sold as 'SS-31' on the research-chemical market (unregulated).
  • Reconstitution: Supplied as a ready solution containing benzyl alcohol as preservative; not reconstituted.
  • Storage: Unopened vials refrigerated at 2–8 °C, do not freeze; once opened may be refrigerated or kept at 20–25 °C; discard 8 days after first opening.

Safety signals on record

  • Reported adverse events: Injection-site reactions in essentially everyone treated in the Barth trial (redness 100 %, pain 75 %, hardening 67 %, itching 67 % vs 25/42/17/17 % on placebo); raised eosinophil counts without symptoms.
  • Contraindications: Serious hypersensitivity to elamipretide or any ingredient. Warnings: serious allergic reactions (do not rechallenge); contains benzyl alcohol, so not for neonates and not for intravenous use.
  • Interactions: No meaningful CYP inhibition or induction in vitro; inhibits the kidney transporter MATE1 in vitro. IV elamipretide did not alter aspirin, clopidogrel or heparin in clinical studies.
  • Notes: Cleared almost entirely by the kidneys (about 100 % recovered in urine within 48 h); exposure rises 39 % to 125 % with worsening kidney function, hence the halved dose in severe impairment. No human pregnancy data. Terminal half-life is not stated in the US label: not established here.

Sources

  1. FORZINITY (elamipretide) injection — US Prescribing Information (DailyMed, setid 146bf34c-76f2-48db-ac07-fb29cce2cd75) (2025)
  2. FDA Grants Accelerated Approval to First Treatment for Barth Syndrome (FDA press announcement, 19 Sep 2025) (2025)
  3. Reid Thompson W 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;23:471-478 (2021)
  4. Thompson WR et al. Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER. Genet Med 2024;26:101138 (2024)
  5. Karaa A et al. Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial. Neurology 2023;101:e238-e252 (2023)

General wellness education, not medical advice. Unapproved compounds have no established dosing, purity standard, or safety profile.

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