SS-31 (elamipretide): evidence and approval status

Summary

SS-31 (elamipretide) is a four amino acid peptide that concentrates in mitochondria, the cell's energy producers, and binds cardiolipin to stabilize the electron transport chain, the machinery that makes cellular energy. It received FDA accelerated approval (an early approval that still requires confirmatory evidence) in September 2025 as Forzinity for Barth syndrome, a rare mitochondrial disease, based on a small crossover trial (each patient got drug and placebo in turn) plus open label extension data, while the 218 person MMPOWER-3 trial in primary mitochondrial myopathy (inherited muscle weakness from faulty mitochondria) did not meet its primary endpoints for walking distance or fatigue. It is available only by prescription for its approved indication, and the research chemical versions sold as SS-31 are not lawful for human use.

What is SS-31 (elamipretide)?

SS-31 (elamipretide) is a synthetic mitochondria targeted tetrapeptide (D-Arg-Dmt-Lys-Phe-NH2) that binds cardiolipin on the inner mitochondrial membrane. It is also known as Elamipretide, Forzinity, MTP-131, Bendavia, D-Arg-Dmt-Lys-Phe-NH2, Szeto-Schiller peptide 31, SS31, SS-31 peptide, SS31 peptide.

How does it work?

Elamipretide is a cell permeable, aromatic cationic tetrapeptide that accumulates in the inner mitochondrial membrane and binds cardiolipin, the phospholipid that organizes respiratory chain supercomplexes. By stabilizing cardiolipin and cristae structure it improves electron transport efficiency, increases ATP production, and reduces reactive oxygen species generation during ischemia and reperfusion. These effects were shown in isolated mitochondria and rodent models and are the basis for trials in mitochondrial diseases, heart failure, and eye disease.

Key facts
Cluster	Longevity and mitochondrial
Routes	Subcutaneous injection once daily (Forzinity label and trials); Intravenous infusion (earlier cardiac and kidney trials)
Conditions studied	Muscle recovery and injury; Longevity and healthy aging; Muscle wasting and sarcopenia; Mitochondrial disease and dysfunction
Record	v3, draft, verified Sep 27, 2026

SS-31 benefits: what the evidence shows

Human RCT evidenceGrade assigned per the methodology.

Multiple randomized human trials with mixed results. TAZPOWER (12 boys and men with Barth syndrome, 12 week crossover) did not meet its primary endpoints, but the 168 week open label extension showed sustained improvements in 6 minute walk distance and muscle strength that supported accelerated approval. MMPOWER-3 (218 adults with primary mitochondrial myopathy, 24 weeks of 40 mg daily) showed no significant difference from placebo in 6 minute walk distance or fatigue score. Earlier phase 2 trials in heart failure and other conditions were also negative or inconclusive. Elamipretide is generally well tolerated apart from injection site reactions.

Indexed studies by evidence grade
Evidence type	Indexed studies	Participants (human)
Human randomized trials	2	230
Human observational studies	1	10
Animal studies	1	n/a
All indexed studies	4	240

Human evidence

TAZPOWER (Reid Thompson 2021): 12 participants with Barth syndrome, 40 mg subcutaneously daily versus placebo in a 12 week crossover; primary endpoints (6 minute walk test and fatigue) did not differ significantly, but the open label extension showed improvement in 6 minute walk distance and knee extensor strength over 36 weeks and sustained gains at 168 weeks (Thompson 2024). MMPOWER-3 (Karaa 2023): 218 adults with genetically confirmed primary mitochondrial myopathy randomized to 40 mg daily or placebo for 24 weeks; no significant difference in 6 minute walk distance (least squares mean difference about 4 meters) or total fatigue score; injection site reactions were the main adverse events.

Animal evidence

In isolated mitochondria and rodent ischemia models, SS-31 binds cardiolipin, restores respiratory chain function, re-energizes ischemic mitochondria, and reduces reperfusion injury in kidney and heart. Rodent studies also report improvements in aged muscle mitochondrial function and in models of heart failure and retinal disease. These preclinical results informed the human trial program.

Key studies

Indexed studies of SS-31 (elamipretide)
Study	Design and population	Outcome	Grade
The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin2013 PMID 23813215	Mechanistic study in isolated mitochondria and rat kidney ischemia modelIsolated mitochondria and rats	SS-31 bound cardiolipin, restored electron transport and ATP synthesis after ischemia, and reduced reperfusion injury	Evidence: Animal-only evidence
A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome (TAZPOWER)2021 PMID 33077895	Randomized, double blind, placebo controlled 12 week crossover followed by open label extensionn = 12 Boys and men with genetically confirmed Barth syndrome	Primary endpoints not met in the crossover; open label extension showed improved 6 minute walk distance and muscle strength at 36 weeks	Evidence: Human RCT evidence
Efficacy and safety of elamipretide in individuals with primary mitochondrial myopathy: the MMPOWER-3 randomized clinical trial2023 PMID 37268435	Randomized, double blind, placebo controlled trial, 24 weeksn = 218 Adults with genetically confirmed primary mitochondrial myopathy	No significant difference from placebo in 6 minute walk distance or total fatigue score; injection site reactions were the main adverse event	Evidence: Human RCT evidence
Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER2024 PMID 38602181	Open label extension of a randomized trialn = 10 Participants with Barth syndrome who continued elamipretide	Sustained improvements in 6 minute walk distance, muscle strength, and cardiac stroke volume over 168 weeks; injection site reactions common	Evidence: Human observational evidence

Conditions studied

Conditions with evidence for SS-31 (elamipretide)
Condition	Grade	Note
Muscle recovery and injury	Not graded	Peptides marketed for muscle recovery include BPC-157, TB-500, PEG-MGF, IGF-1 LR3, and growth hormone secretagogues. Human evidence for muscle healing is absent for all of them; the supporting data are rodent muscle transection models and mechanistic cell work. Several are WADA prohibited.
Longevity and healthy aging	Evidence: Human RCT evidence	Elamipretide trials in primary mitochondrial myopathy and Barth syndrome; mixed primary endpoints; FDA approved for Barth syndrome in 2025.
Muscle wasting and sarcopenia	Evidence: Human RCT evidence	Elamipretide missed its walking and fatigue endpoints in MMPOWER-3 (n = 218) in primary mitochondrial myopathy.
Mitochondrial disease and dysfunction	Evidence: Human RCT evidence	Barth syndrome crossover missed its primary endpoints, with gains in walking distance and strength in the open label extension; MMPOWER-3 (n = 218) was negative; FDA approved as Forzinity for Barth syndrome.

Is SS-31 (elamipretide) legal in the United States?

FDA approvedNot WADA prohibited

FDA and compounding status

FDA granted accelerated approval to elamipretide (Forzinity) in September 2025 for Barth syndrome, making it the first approved treatment for that disease. Because an FDA approved product exists, elamipretide is not eligible for routine 503A compounding, and it has not been listed on the 503A bulks list. Material sold online as SS-31 for research use is not the approved drug and is not lawful for human use.

WADA status

Not WADA prohibited. Not named on the current prohibited list. Athletes should still confirm against the list in force for their season.

Regulatory timeline

Sep 2025FDA
FDA grants accelerated approval of elamipretide for Barth syndrome
In September 2025 FDA granted accelerated approval of elamipretide (SS-31), a mitochondria-targeted tetrapeptide, for Barth syndrome, following an earlier complete response letter. Continued approval depends on confirmatory evidence.
Regulatory: FDA approvedSource: DailyMed: elamipretide labeling

Full tracker for SS-31 (elamipretide) or the category-wide tracker.

SS-31 (elamipretide) dosing: FDA label and trial doses

Doses below are quoted from the FDA label for its approved uses, plus the doses used in the pivotal trials where noted. The prescriber sets the dose; PeptideAgent does not recommend doses or protocols.

Clinical trials in Barth syndrome (TAZPOWER) and primary mitochondrial myopathy (MMPOWER-3) used 40 mg subcutaneously once daily. The Forzinity prescribing information on DailyMed gives the approved weight based dosing for Barth syndrome; PeptideAgent does not restate label dosing beyond the trial regimen. No dose has been established for any other use.

Routes reported

Routes of administration reported for SS-31 (elamipretide)
#	Route
1	Subcutaneous injection once daily (Forzinity label and trials)
2	Intravenous infusion (earlier cardiac and kidney trials)

SS-31 side effects

Side effects

Side effects reported for SS-31 (elamipretide)
#	Reported side effect
1	Injection site reactions (erythema, pruritus, pain), the most common adverse event in every trial
2	Headache
3	Dizziness
4	Eosinophilia reported in some trial participants
5	Long term safety beyond the extension studies is not established

Interactions

Interactions reported for SS-31 (elamipretide)
#	Interaction
1	No clinically significant drug interactions were identified in the trial program; consult the Forzinity label for current information
2	No formal interaction studies with other mitochondrial supplements such as coenzyme Q10 or NAD precursors

Contraindications

Contraindications for SS-31 (elamipretide)
#	Contraindication
1	No contraindications listed in the approved label as of the last verification date; check DailyMed for updates
2	Pregnancy and breastfeeding: no adequate human data
3	Use outside the approved indication should be limited to clinical trials

How do people access SS-31 (elamipretide) legally?

Typical cost: Forzinity pricing for Barth syndrome is set for a rare disease and is largely covered through specialty pharmacy and manufacturer patient programs; a cash price is not publicly listed. Research chemical listings for SS-31 exist but those products are not lawful for human use.

Verified access options

Step 1
Prescription from a specialist for Barth syndrome, dispensed through specialty pharmacy as Forzinity.
Step 2
Clinical trials for other mitochondrial and age related conditions.
Step 3
Products labeled research use only are not lawful for human use and are not verified for purity.

Access paths are verified against public regulatory records and prescriber licensing. We never list unlicensed vendors.

Compare SS-31 (elamipretide)

MOTS-c vs SS-31 (elamipretide)

Frequently asked questions

What is SS-31 peptide?

SS-31, now named elamipretide, is a synthetic four amino acid peptide that concentrates in mitochondria, the cell's energy producers, and binds cardiolipin, a lipid that holds the energy producing machinery together. FDA approved it as Forzinity to improve muscle strength in patients with Barth syndrome, a rare inherited mitochondrial disease, weighing at least 30 kg, under accelerated approval, an early approval that still requires confirmatory evidence. SS-31 sold online for energy or anti-aging is not the approved product and is not lawful for human use. [1] [5]

Is SS-31 (elamipretide) FDA approved?

Yes, for one indication. FDA granted accelerated approval to elamipretide as Forzinity in September 2025 for Barth syndrome, a rare inherited mitochondrial disease. It is not approved for primary mitochondrial myopathy, heart failure, aging, or athletic performance, and it is available only by prescription. [2] [5]

Does elamipretide work for mitochondrial disease?

The evidence is mixed. In Barth syndrome, the 12 person TAZPOWER crossover missed its primary endpoints, but the open label extension showed sustained gains in walking distance and strength over 168 weeks, which was enough for accelerated approval. In primary mitochondrial myopathy, the 218 person MMPOWER-3 trial found no significant improvement in walking distance or fatigue versus placebo. [2] [3] [4]

What are the side effects of elamipretide?

Injection site reactions such as redness, itching, and pain are by far the most common adverse event and occurred in most treated participants in MMPOWER-3. Headache and dizziness were also reported. Serious adverse events were not more common than placebo in the randomized trials, but long term safety data come from small open label extensions. [3] [4]

What is the elamipretide (Forzinity) dose on the FDA label?

The Forzinity label dose for Barth syndrome patients weighing at least 30 kg is 40 mg injected under the skin once daily, at the same time each day. Adults with severe kidney impairment (eGFR under 30 mL per minute and not on dialysis) take 20 mg once daily. A missed dose is skipped, not doubled. The Barth syndrome and mitochondrial myopathy trials also used 40 mg daily. [3] [5]

How much does elamipretide cost?

Forzinity is priced as a rare disease drug and dispensed through specialty pharmacies, usually with insurance coverage and manufacturer support for eligible Barth syndrome patients; no public cash price was verified. SS-31 sold by research chemical sellers is not the approved product and is not lawful for human use. [5]

Is SS-31 banned by WADA?

Elamipretide is an FDA approved drug and is not named in any section of the WADA Prohibited List as of the 2026 list or the 2027 list published in September 2026, so it is not prohibited. Athletes should still confirm with their anti-doping organization, because unapproved research versions and future list changes could alter that answer. [5] [6] [7]

Does SS-31 work as an anti-aging or longevity peptide?

No human trial has tested elamipretide for aging. In rodents it improves mitochondrial function in aged muscle and heart, which drives the longevity marketing. The human trials are in genetic mitochondrial diseases, and the largest one was negative. There is no evidence in healthy adults. [1] [3]

SS-31 vs MOTS-c: what is the difference?

Both target mitochondria, but SS-31 (elamipretide) is a synthetic drug that binds cardiolipin and has an FDA approval and several randomized trials, while MOTS-c is a natural mitochondrial encoded peptide with mouse data only and no human trial. Elamipretide is a prescription product; MOTS-c is awaiting an FDA compounding rule after a 2026 advisory committee recommendation. [1] [5]

Decisions about starting, stopping, or combining any treatment belong with a licensed clinician who knows your history.

Sources

Numbered citations above point to these primary sources. PubMed entries link to the indexed abstract.

Cite this page

Free to cite and quote with a link. Data is licensed CC BY 4.0 with attribution to PeptideAgent.

APA style: PeptideAgent. (2026, September 27). SS-31 (elamipretide): evidence, legality, and access. https://peptideagent.ai/peptides/ss-31
HTML link: <a href="https://peptideagent.ai/peptides/ss-31">SS-31 (elamipretide): evidence, legality, and access</a>, PeptideAgent, updated September 27, 2026.

SS-31 peptide (elamipretide, Forzinity)

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