SS-31 is also known as elamipretide. Forzinity, the approved elamipretide product, most commonly caused local injection-site reactions in its small Barth syndrome trial. That product's label is a better source for reaction rates than unsourced claims about generic SS-31 research vials.
Current approval status
FDA granted accelerated approval to Forzinity on September 19, 2025, to improve muscle strength in patients with Barth syndrome weighing at least 30 kg. The earlier version of this article incorrectly said elamipretide was unapproved in May 2026. FDA approval announcement
Injection-site reactions in the labeled trial
The crossover study included 12 male participants with genetically confirmed Barth syndrome. These rates describe that small study population and formulation.
| Reaction | Elamipretide | Placebo |
|---|---|---|
| Redness | 12 of 12 | 3 of 12 |
| Pain | 9 of 12 | 5 of 12 |
| Induration | 8 of 12 | 2 of 12 |
| Itching | 8 of 12 | 2 of 12 |
| Bruising | 3 of 12 | 0 of 12 |
Forzinity prescribing information, section 6.1 also describes hypersensitivity and eosinophil findings. Its extension included exposure beyond three years in some participants, so the previous blanket claim that all human exposure data ended near one year was inaccurate.
Why product identity changes the interpretation
An ingredient name does not identify the exact finished formulation. A reaction frequency observed for a specified medicine cannot be assumed to describe every other product carrying the same ingredient name. Likewise, a laboratory purity percentage alone does not establish that two finished products are equivalent.
From the FormBlends catalog
SS-31 (Elamipretide)
Mitochondria-targeted peptide that restores cellular energy production · From $79/mo · compounded by a licensed 503A pharmacy, dispensed only after provider review.
Learn about SS-31 (Elamipretide) →What the data does not tell us
A small trial can describe what happened to its participants, but it cannot establish every possible outcome in broader populations or in other formulations. Comparing headline percentages across unrelated studies also mixes different designs, follow-up periods and populations. The relevant comparison here is the within-study placebo comparison shown above.
Frequently asked questions
Are injection-site reactions common?
Yes, they were the main reported reactions in the labeled Barth syndrome crossover study. The table gives participant counts rather than implying a universal rate.
Is every SS-31 product FDA-approved?
The approval is for Forzinity and its specified indication. A research product using the SS-31 name is a different product record.
Related resources
Platform: This page is published by FormBlends for informational and educational purposes only. FormBlends is not a licensed pharmacy, medical practice, or healthcare provider. Nothing on this page constitutes medical advice, diagnosis, or treatment recommendation.
Research Compound: Elamipretide is FDA-approved as Forzinity for a specified Barth syndrome population. Other products sold as research SS-31 are not the approved Forzinity product. Its use outside an IRB-approved protocol or physician-supervised compounding program is not endorsed by FormBlends.
Results: Individual outcomes vary. Safety and efficacy data cited on this page derive from clinical trials conducted under controlled conditions with pharmaceutical-grade material and clinical oversight. These conditions may not replicate those of any individual's use.
Trademark: Elamipretide, Bendavia, and MTP-131 are trade names associated with their respective holders. FormBlends has no affiliation with Stealth BioTherapeutics or any other elamipretide developer. Product and company names are used solely for factual identification.
Ready when you are
SS-31 (Elamipretide)
Mitochondria-targeted peptide that restores cellular energy production · From $79/mo · compounded by a licensed 503A pharmacy, dispensed only after provider review.
Learn about SS-31 (Elamipretide) →