Elamipretide: the basics
What is it?
A small prescription peptide, just four amino acids long, designed to reach mitochondria, the energy-making parts of cells.
Research paper 1 ↗Research paper 2 ↗What do people claim it helps with?
Improving muscle strength in Barth syndrome is an approved use. Online claims about anti-aging, energy, eyesight or heart health go well beyond that.
What has research actually shown?
Approval is based on knee-muscle strength gains during long-term open-label treatment in a tiny Barth syndrome study. Larger trials in other muscle diseases and heart failure did not show benefit.
Research paper 1 ↗Research paper 2 ↗Has this been demonstrated in people?
Human trials, but the key Barth syndrome evidence comes from only 12 patients, and the placebo-controlled part missed its main goals. FDA requires a confirmatory trial.
Research paper 1 ↗Research paper 2 ↗What side effects, risks and unknowns should I understand?
Injection-site reactions are the most common side effect. Serious allergic reactions have been reported. It contains benzyl alcohol, so it is not for newborns.
Prescribing information ↗Is it an approved medicine?
Yes. FDA granted accelerated approval to Forzinity (elamipretide) in September 2025 to improve muscle strength in Barth syndrome; continued approval may depend on a confirmatory trial.
FDA safety information 1 ↗Prescribing information 2 ↗Approval here means U.S. FDA approval and applies to a particular product, formulation and use. This is a starting overview, not a complete side-effect list. Sources checked 10 October 2026; independent scientific review pending.
How is it used or studied?
Prescription injection under the skin, given once daily as directed by a specialist.
Different routes and formulations can have different effects. A study of one product does not validate every product with the same peptide name.
A common misunderstanding
'SS-31' sold online is not the FDA-approved Forzinity product, and Barth syndrome results do not show benefits for healthy people.
What should I ask a clinician?
- What diagnosis or goal are we trying to address, and what established options are available?
- Was the expected benefit shown in people like me, using this exact product?
- How could my medicines, health conditions or pregnancy plans affect the risks?
- What monitoring is needed, and what would tell us the treatment is helping or should be stopped?
What do the research words mean?
- Peptide
- A short chain of amino acids, the building blocks of proteins.
- Preclinical
- Research in cells, tissues or animals before dependable treatment evidence in people.
- Controlled trial
- A study comparing a treatment with another treatment or a placebo to help separate its effects from other explanations.
- Biomarker
- A measurement, such as a hormone level. A change does not necessarily mean someone feels better or lives longer.
Elamipretide Evidence & Clinical Profile
Established Clinical Trials
Elamipretide has been investigated in clinical contexts. Patient outcomes must be evaluated against study size, design, and control cohorts.
Laboratory & In Vivo Assays
Cellular and animal disease models examine receptor binding affinities and signaling cascades, which require human confirmation.
What is Elamipretide?
Elamipretide (Forzinity) is A four-amino-acid peptide that binds cardiolipin in the inner mitochondrial membrane. In September 2025 FDA granted accelerated approval to Forzinity (elamipretide) as the first treatment for Barth syndrome, a rare inherited mitochondrial disease, based on knee-muscle strength gains in a very small trial. A confirmatory trial is required, and phase 3 and phase 2 trials in other conditions did not meet their main goals. Aliases include: Forzinity, SS-31, MTP-131, Bendavia, Szeto-Schiller peptide.
- Sequence (one-letter)
- D-Arg-Dmt-Lys-Phe-NH2
- Molecular formula
- C32H49N9O5
- Molecular weight
- 639.8 g/mol (free base)
- CAS Number
- 736992-21-5
- UNII Code
- 87GWG91S09
- PubChem CID
- 11764719
Identifiers checked against PubChem and FDA's Global Substance Registration System on 13 October 2026. FDA substance record ↗ · PubChem record ↗ See all names and codes in the peptide name index.
Clinical Trials & Human Cohorts
Human research can examine tolerability, symptoms or patient outcomes. The design and comparator determine what each result can establish.
Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER [1]
What was reported
During open-label treatment, 6-minute walk distance and knee-muscle strength improved from extension baseline. The FDA label states elamipretide was not superior to placebo on the randomized trial's primary endpoints.
What limits the conclusion
Very small, open-label extension with no control group; several authors are Stealth BioTherapeutics employees or received company support.
Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial [2]
What was reported
No improvement in 6-minute walk distance or fatigue score at 24 weeks versus placebo; treatment was generally well tolerated.
What limits the conclusion
Negative for the tested population; a post hoc genotype analysis is hypothesis-generating only.
Effects of Elamipretide on Left Ventricular Function in Patients With Heart Failure With Reduced Ejection Fraction: The PROGRESS-HF Phase 2 Trial [3]
What was reported
No improvement in left ventricular volume or ejection fraction after 4 weeks; adverse events were similar across groups.
What limits the conclusion
Short treatment period and a structural imaging endpoint.
How the compound may work
Mechanisms describe how Elamipretide may affect biological processes. Laboratory findings and patient outcomes answer different questions.
Cardiolipin binding
FDA describes elamipretide as a mitochondrial cardiolipin binder that localizes to the inner mitochondrial membrane and improves mitochondrial morphology and function. [4]
Membrane surface electrostatics
Laboratory work found SS-31 binds lipid bilayers and changes their surface charge, which may alter calcium distribution and reduce calcium stress in mitochondria. The peptide's inventor co-authored this work. [6]
Areas Being Studied
These research topics reflect active areas of scientific exploration, distinct from unverified commercial marketing claims.
Barth syndrome
Approved to improve muscle strength; FDA requires a randomized, placebo-controlled confirmatory trial. [5]
Primary mitochondrial myopathy
MMPOWER-3 did not meet its primary endpoints. [2]
Dry age-related macular degeneration
A sponsor phase 3 trial (ReNEW) is active but not recruiting; no results are available. [10]
Aging biology
Cardiolipin-targeted peptides are studied for age-related mitochondrial decline; these findings are preclinical and come largely from the inventor's laboratory. [7]
Compare the study designs.
| Study | Design / sample | Outcome type | Key limitation |
|---|---|---|---|
| TAZPOWER extension (Barth) · 2024 [1] | 28-week randomized double-blind crossover trial followed by 168-week open-label extension n = 12 |
Clinical endpoint evaluation | Very small, open-label extension with no control group; several authors are Stealth BioTherapeutics employees or received company support. |
| MMPOWER-3 (mitochondrial myopathy) · 2023 [2] | Phase 3 randomized double-blind placebo-controlled trial n = 218 |
Clinical endpoint evaluation | Negative for the tested population; a post hoc genotype analysis is hypothesis-generating only. |
| PROGRESS-HF (heart failure) · 2020 [3] | Phase 2 randomized double-blind placebo-controlled trial n = 71 |
Clinical endpoint evaluation | Short treatment period and a structural imaging endpoint. |
Regulatory Status & Clinical Safety
Regulatory Classification
FDA accelerated approval (NDA 215244, September 19, 2025) as Forzinity to improve muscle strength in adult and pediatric patients with Barth syndrome who meet the label's minimum body weight. Continued approval may depend on a confirmatory trial. Contraindicated after serious hypersensitivity; not for use in neonates (benzyl alcohol). Not named on WADA's 2026 Prohibited List.
Safety Realities & Impurities
Safety depends on the molecule, formulation, route and evidence. A laboratory purity measurement alone cannot establish safety for human use.
Clinical Trials Registry Records
Official registry records from ClinicalTrials.gov. Study registration does not imply government endorsement or guaranteed efficacy.
A Trial to Evaluate Safety, Tolerability and Efficacy of Elamipretide in Subjects With Barth Syndrome [8]
- Planned enrollment
- 12 (patients)
- Posted results
- Available
- Sponsor
- Stealth BioTherapeutics Inc.
- Last updated
- 2024
A Trial to Evaluate Safety and Efficacy of Elamipretide Primary Mitochondrial Myopathy Followed by Open-Label Extension [9]
- Planned enrollment
- 218 (patients)
- Posted results
- Available
- Sponsor
- Stealth BioTherapeutics Inc.
- Last updated
- 2022
ReNEW:Phase 3 Study of Efficacy, Safety & Pharmacokinetics of Subcutaneous Injections of Elamipretide in Subjects With Dry Age-Related Macular Degeneration (Dry AMD) [10]
- Planned enrollment
- 313 (patients)
- Posted results
- Pending in registry
- Sponsor
- Stealth BioTherapeutics Inc.
- Last updated
- 2026
Clinical Trial in Patients With Barth Syndrome- 4TAZPower [11]
- Planned enrollment
- 48 (patients)
- Posted results
- Pending in registry
- Sponsor
- Stealth BioTherapeutics Inc.
- Last updated
- 2026
WADA & Anti-Doping Regulations
WADA Anti-Doping Status
Elamipretide is not prohibited under current World Anti-Doping Agency (WADA) regulations. However, athletes must ensure unregulated preparations or unverified vendor products do not violate Section S0 (Non-approved substances). Last verified: October 2026.
Research Timeline
-
2020
Heart-failure trial negative
PROGRESS-HF finds no change in heart structure or function at 4 weeks. [3]
-
2023
MMPOWER-3 negative
Phase 3 trial in primary mitochondrial myopathy misses its primary endpoints. [2]
-
2024
TAZPOWER extension published
168-week open-label results in Barth syndrome report functional and cardiac improvements. [1]
-
2025
FDA accelerated approval
FDA approves Forzinity as the first treatment for Barth syndrome, with a confirmatory trial required. [5]
-
2026
Post-approval trial recruiting
A phase 4 Barth syndrome trial (4TAZPower) is recruiting. [11]
What Researchers Still Don't Know
Long-term safety profiles
Multi-year observational data in broader heterogeneous cohorts remains uncharacterized.
Optimal dose-response thresholds
Comparative trials optimizing minimal effective exposure versus adverse event rates.
Formulation bioavailability
Differences between oral, subcutaneous, and modified peptide delivery vehicles.
References
Primary sources verified against PubMed / NLM and regulatory databases.
- Open-label extension of RCT
- Phase 3 RCT
- Phase 2 RCT
-
FDA Drug Label
Forzinity (elamipretide) injection Prescribing Information ↗ (external website)
-
FDA Press Release
FDA Grants Accelerated Approval to First Treatment for Barth Syndrome ↗ (external website)
- Laboratory study
- Review
- Registry Record
- Registry Record
- Registry Record
-
Registry Record
NCT07531251 Clinical Trial in Patients With Barth Syndrome- 4TAZPower ↗ (external website)
-
Drugs@FDA record
Drugs@FDA: NDA 215244 Forzinity (elamipretide hydrochloride) ↗ (external website)