For research and laboratory use only. Nothing here is medical advice. Research-grade SS-31 is not an approved medicine and is not for human consumption, medical use, diagnosis, or treatment.
Peptide research hit a genuine milestone in 2025: elamipretide — the pharmaceutical name for SS-31 — was approved by the FDA under the brand name Forzinity for Barth syndrome. That made it the first mitochondria-targeted peptide ever to become a licensed medicine.
For anyone researching mitochondrial peptides, this is the single most important credibility event in the field. Here’s what actually happened, what the trials showed, and what it does (and doesn’t) mean.
First, the Names
SS-31, elamipretide, Bendavia and Forzinity are all the same molecule — a four-amino-acid peptide that binds cardiolipin in the inner mitochondrial membrane. “SS-31” is the research literature name; “elamipretide” is the clinical name; “Forzinity” is the approved brand. If you want the mechanism explained properly, start with our complete SS-31 pharmacology profile.
What Is Barth Syndrome?
Barth syndrome is an ultra-rare inherited disorder caused by mutations in the TAZ gene, which makes tafazzin — an enzyme needed to build mature cardiolipin. Without proper cardiolipin, mitochondrial membranes malform. Patients (almost all male) suffer heart muscle weakness, skeletal muscle fatigue and reduced life expectancy.
Spot the connection: Barth syndrome is essentially a disease of broken cardiolipin, and SS-31 is a cardiolipin-binding peptide. It’s the cleanest possible test of the mechanism.
The Trial Data
The core evidence came from the TAZPOWER trial and its long-term extension, plus a natural history comparison:
- In the extension study, elamipretide-treated patients improved their 6-minute walk distance by ~80–91 metres versus untreated natural-history controls at weeks 64–76 (published comparison study)
- Over 168 weeks of treatment, patients showed sustained improvements in physical ability and cardiac measures
- Dosing was 40mg subcutaneously once daily throughout
The FDA review (briefing document, NDA 215244) wrestled with the tiny patient population — Barth syndrome affects a few hundred people worldwide — but the approval landed in 2025, with the story tracked closely by the United Mitochondrial Disease Foundation.
Side Effect Profile
Across the clinical programmes — Barth syndrome, mitochondrial myopathy, dry AMD and heart failure trials — elamipretide was consistently well tolerated. The most common finding by far: mild-to-moderate injection-site reactions (redness, itching, swelling) that typically settled over time. No characteristic organ toxicity signal emerged, though regulators noted the overall safety database is small.
Worth knowing if you’re reading community reports: local skin reactions were reported in over half of patients in the trial data, so they are the expected finding rather than the exception.
For a peptide that’s been through this many human programmes, that’s an unusually quiet safety sheet — and it’s a major reason research interest keeps compounding.
What the Approval Validates (and What It Doesn’t)
It validates the mechanism. Cardiolipin binding isn’t a whiteboard theory anymore — a regulator has accepted that stabilising cardiolipin produces measurable functional improvement in humans whose cardiolipin is defective.
It validates the safety approach. Years of daily subcutaneous human dosing at 40mg with injection-site reactions as the headline finding.
It does not make research SS-31 a medicine. Forzinity is a licensed pharmaceutical for one ultra-rare disease. Research-grade SS-31 sold in the UK remains strictly a laboratory compound for in vitro and in vivo study — not for human consumption, and not interchangeable with a regulated drug product. It also holds no MHRA marketing authorisation in the UK.
Where Research Goes Next
Elamipretide programmes continue in mitochondrial myopathy and ophthalmology, while the wider field runs at ageing questions: ADP sensitivity in aged muscle, cardiac ischemia-reperfusion, renal protection, neurodegeneration. And increasingly, combination work — pairing SS-31’s structural repair with signalling peptides like MOTS-c (see SS-31 vs MOTS-c for why order matters, and our guide to MOTS-C side effects and the cancer question for the activation half of that sequence).
For laboratory protocols, click conversions and study-length norms, the SS-31 dosing and cycles guide covers the practical side.
Elamipretide FAQs
Is elamipretide the same as SS-31?
Yes — identical molecule. Elamipretide is the clinical development name; SS-31 is the research name; Forzinity is the approved brand.
What is elamipretide approved for?
Barth syndrome — a rare inherited cardiolipin disorder. It is not approved for any other condition.
What were elamipretide’s main side effects in trials?
Mild-to-moderate injection-site reactions were the most commonly reported adverse events, affecting over half of patients in the trial data. The safety database remains limited due to small trial populations.
Does the FDA approval apply to research SS-31?
No. The approval covers the pharmaceutical product Forzinity only. Research-grade SS-31 remains a laboratory compound, strictly not for human use, with no MHRA marketing authorisation in the UK.
Why does an ultra-rare disease approval matter to mitochondrial researchers?
Because Barth syndrome is a pure cardiolipin defect, the approval is human proof-of-concept for SS-31’s core mechanism — cardiolipin stabilisation improving mitochondrial function.
The Takeaway
A peptide first synthesised for lab research has crossed the line into licensed medicine, on the exact mechanism the research community has studied for a decade. The field just got its credibility stamp. If you’re studying that mechanism, use verified material — every MyReta SS-31 Peptide Pen 20mg batch is independently tested to ≥99% purity (COA reports).