Gathering the record
Relay is organizing the evidence and source boundaries.
Mitochondrial cardiolipin-binding tetrapeptide
SS-31 is an earlier research name for elamipretide. The prescription product FORZINITY received accelerated FDA approval for one narrow Barth-syndrome indication. That approval does not establish general benefits for energy, recovery, performance, anti-aging, or other mitochondrial conditions.
60-Second Overview
Start with what it is, why it matters, what research has shown, and what remains unknown. The science follows after the orientation.
Start here. These four answers explain why the compound matters before the page introduces the deeper science.
SS-31 is an earlier research name for elamipretide, a small peptide developed to influence mitochondria—the cell structures that help produce energy—and their inner membranes.
Researchers have tested whether supporting mitochondrial function can improve outcomes in rare genetic disease, muscle disease, heart failure, and eye disease. The findings are therefore condition-specific rather than one general result.
Results differ by condition. FORZINITY received accelerated FDA approval in a narrow Barth syndrome population based on an intermediate measure, with confirmation still required. Several controlled programs did not meet their main measures of benefit.
The Barth clinical benefit still requires confirmation, and evidence does not establish a general energy, recovery, performance, or longevity effect. The approved finished solution does not validate powdered SS-31 vials.
The research depth, routes, studies, and primary sources below explain how Relay knows—and where the evidence stops.
Research context
Published research has investigated this compound using the following study designs.
These records explain what researchers did. They are not instructions, recommendations, or a transferable protocol.
Current FDA labeling describes FORZINITY for a specific Barth syndrome population using a ready-to-use finished solution.
Reported study administration—not a recommendation.
Research at a glance
Evidence depth, confidence, and route context explain how Relay knows—not what anyone should do.
Elamipretide has controlled Phase 2 and Phase 3 trials, long-term extension data, pharmacology studies, and a current accelerated-approval program.
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
The approved Barth-syndrome endpoint is supported by a very small open-label extension, while several larger controlled programs did not meet their primary endpoints.
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Route-specific record
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Evidence can change by administration method. Findings from one route should not automatically be applied to another.
Evidence boundary: The randomized TAZPOWER period did not improve its primary walk or fatigue endpoints; accelerated approval relied on a different intermediate endpoint observed during open-label follow-up. The finished solution label does not validate a lyophilized SS-31 vial, bacteriostatic-water volume, independent concentration, or generic-vial stability period. Amounts shown describe cited research exposure—not a dosage recommendation.
Detailed evidence
Start with the strongest supported conclusion and its main uncertainty. Claim-level records below show how the evidence changes by question, population, route, formulation, and study design.
FDA accelerated approval for a genetically confirmed Barth-syndrome population weighing at least 30 kg, supported by a 12-person crossover trial and its very small long-term open-label extension. A randomized post-approval trial is required to verify clinical benefit.
This is the strongest supported conclusion in the current human evidence—not a summary of every claim made about the compound.
Whether the knee-strength change predicts meaningful functional benefit in Barth syndrome, plus long-term and rare safety and any efficacy outside the approved population.
Keeping the main uncertainty visible prevents an early or promising finding from looking more settled than it is.
Questions people bring to the evidence
Research questions—not promises of benefit.
Elamipretide is the established drug name; SS-31, MTP-131, and Bendavia are earlier research or development names. FORZINITY is the FDA-approved elamipretide-hydrochloride product.
FDA classifies FORZINITY as a mitochondrial cardiolipin binder that improves mitochondrial morphology and function.
The approval covers improving muscle strength in adult and pediatric patients with Barth syndrome who weigh at least 30 kg.
After 12 weeks, neither six-minute walk distance nor Barth-specific fatigue differed significantly from placebo; knee extensor strength also did not differ significantly in that controlled period.
FDA judged that improvement in this intermediate endpoint was reasonably likely to predict patient benefit, but the benefit still requires confirmation.
MMPOWER-3 found no improvement versus placebo in six-minute walk distance or fatigue at 24 weeks.
PROGRESS-HF did not improve its principal ventricular measures, and ReCLAIM-2 did not meet its co-primary vision and geographic-atrophy outcomes.
4TAZPower is designed to confirm Barth clinical benefit after accelerated approval; ReNEW is testing an imaging endpoint in dry AMD.
The approved product is a ready-to-use preserved solution. Its label does not establish reconstitution, sterility, stability, dose, or compatibility for powdered or vendor-supplied materials sold as SS-31.
Clinical effects differ by disease and endpoint. Several controlled programs were negative, and no approved indication covers healthy people.
Mechanisms
Elamipretide is a four-amino-acid aromatic-cationic peptide that binds cardiolipin and localizes to the inner mitochondrial membrane. FDA states that FORZINITY improves mitochondrial morphology and function. Human evidence is disease-specific and mixed: accelerated Barth-syndrome approval rests on an intermediate knee-strength endpoint from a tiny open-label extension, while controlled trials in primary mitochondrial myopathy, stable HFrEF, and dry AMD did not meet key primary efficacy endpoints.
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Studies
Study arms are reported for transparency. They describe what researchers did in a defined record and do not transfer across identities, routes, formulations, or populations.
A later trial phase can ask a more mature question, but it does not guarantee a positive result, regulatory approval, or relevance outside the studied population.
Randomized, double-masked, placebo-controlled, parallel-group trial
Adults aged 55 years or older with dry age-related macular degeneration and geographic atrophy
The trial did not meet either primary efficacy endpoint. Prespecified ellipsoid-zone imaging measures favored elamipretide, but they do not establish a proven visual or geographic-atrophy benefit.
Study administration: Once-daily subcutaneous elamipretide 40 mg or placebo
Limitations: Secondary imaging findings are not substitutes for the negative co-primary outcomes. Elamipretide is not FDA approved for dry AMD.
Randomized, double-blind, placebo-controlled, parallel-group trial
Adults with genetically confirmed primary mitochondrial myopathy
Elamipretide did not improve either co-primary endpoint versus placebo. The between-group difference was -3.2 metres for the six-minute walk test and -0.07 for fatigue.
Study administration: Once-daily subcutaneous elamipretide 40 mg or placebo
Limitations: Results apply to this heterogeneous primary-mitochondrial-myopathy population and protocol. Post hoc genotype analyses are hypothesis-generating and do not replace the negative primary analysis.
Randomized, double-blind, placebo-controlled crossover trial followed by an open-label extension
Twelve male participants aged 12 to 35 years with genetically confirmed Barth syndrome
The randomized crossover period did not show significant differences from placebo in six-minute walk distance, fatigue, knee extensor strength, or other secondary endpoints after 12 weeks.
Study administration: Once-daily subcutaneous elamipretide 40 mg and placebo in crossover sequence
Limitations: Extremely small, single-site trial in a rare disease. The randomized period was short, and the later open-label observations had no concurrent placebo group.
Randomized, double-blind, placebo-controlled crossover trial
Adults with genetically confirmed primary mitochondrial myopathy
The short crossover study reported a signal in six-minute walk performance and some patient-reported measures after four weeks.
Study administration: Once-daily subcutaneous elamipretide under the study protocol and placebo
Limitations: Small, short trial with multiple outcomes. The larger and longer MMPOWER-3 trial did not confirm benefit on the co-primary walk or fatigue endpoints.
Randomized, double-blind, placebo-controlled, three-arm trial
Adults with stable heart failure and reduced ejection fraction
Elamipretide was tolerated but did not improve left ventricular end-systolic volume or ejection fraction versus placebo at four weeks.
Study administration: Once-daily subcutaneous elamipretide 4 mg, elamipretide 40 mg, or placebo
Limitations: Short treatment duration and modest sample size. The study does not establish benefit for heart failure, cardiovascular performance, or general cardiac health.
Single-arm open-label extension of the TAZPOWER crossover trial
Ten TAZPOWER participants entered; eight remained through week 168
Function, fatigue, cardiac measures, and knee extensor strength improved from open-label baseline over time. FDA used the knee-strength change as an intermediate endpoint reasonably likely to predict benefit.
Study administration: Once-daily subcutaneous elamipretide 40 mg
Limitations: No concurrent control, very small cohort, attrition, repeated measures, and possible natural-history, learning, expectation, and time effects. The observations do not independently prove the magnitude of clinical benefit.
Randomized, double-blind, parallel-group, placebo-controlled post-approval trial
Planned participants aged 5 to 55 years with genetically confirmed Barth syndrome
The trial was recruiting and had no posted outcome results by the July 25, 2026 evidence cutoff.
Study administration: Once-daily subcutaneous elamipretide or placebo under the registered protocol
Limitations: Registration describes a plan, not evidence of benefit. Continued accelerated approval may depend on verification and description of clinical benefit.
Randomized, double-masked, placebo-controlled, parallel-group trial
Adults with dry age-related macular degeneration and geographic atrophy
The study was active but no longer recruiting and had no posted outcome results by the evidence cutoff.
Study administration: Once-daily subcutaneous elamipretide 40 mg or placebo under the registered protocol
Limitations: The registry does not establish efficacy. The Phase 2 co-primary outcomes were negative, so any Phase 3 result must be evaluated when reported.
Safety snapshot
No source-qualified adverse-event pattern is represented in the current record.
Evidence boundaryHuman exposure is present, but the record is not detailed enough to characterize a reliable adverse-event pattern.
The current record does not support a reliable common-versus-uncommon frequency split.
Evidence boundaryUnder-detected or under-reported events must not be described as rare.
No source-qualified compound-specific warning or contraindication is encoded in the current record.
Evidence boundaryFDA accelerated approval as FORZINITY to improve muscle strength in adult and pediatric patients with Barth syndrome weighing at least 30 kg. All other uses remain unapproved. Whether the knee-strength change predicts meaningful functional benefit in Barth syndrome, plus long-term and rare safety and any efficacy outside the approved population.
The current record does not identify a reliable compound-specific pattern of events that caused study discontinuation.
Evidence boundaryThis is an evidence gap, not proof that discontinuations did not occur.
No compound-specific patient-facing urgent-action threshold is established in the current Relay record.
Evidence boundaryRelay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
Community
Built by the community
Every structured report adds useful context about research setup, outcomes, and unwanted effects as the community dataset grows.
Publicly anonymous by default. Your account keeps reports editable and helps reduce duplicate submissions.Sources
2026-07-13 · NCT07531251
2025-09-19 · NCT03098797
2025-09-19
2024-10-09 · PMID 39605874 · NCT03891875 · DOI 10.1016/j.xops.2024.100628
2024-04-18 · NCT06373731
2024-04-10 · PMID 38602181 · NCT03098797 · DOI 10.1016/j.gim.2024.101138
2023-06-02 · PMID 37268435 · NCT03323749 · DOI 10.1212/WNL.0000000000207402
2020-10-20 · PMID 33077895 · NCT03098797 · DOI 10.1038/s41436-020-01006-8
2020-02-26 · PMID 32096613 · NCT02805790 · DOI 10.1002/jcsm.12559
2020-02-14 · PMID 32068002 · NCT02788747 · DOI 10.1016/j.cardfail.2020.02.001