Mitochondrial

SS-31 (Elamipretide)

Reviewed 22 October 2026 · How we research

Also known as: Elamipretide, MTP-131, Bendavia, Forzinity

What is SS-31?

SS-31, now called elamipretide, is a small peptide designed to slip into mitochondria — the cell's power plants — and bind cardiolipin, a fat that holds the energy-producing machinery together in the inner membrane.

After years of trials in heart failure, kidney and eye disease, it received accelerated approval from the FDA in 2025 for Barth syndrome, a rare inherited mitochondrial disease, under the brand name Forzinity. It is the most clinically advanced peptide in the mitochondrial category.

How SS-31 works

SS-31 alternates aromatic and positively charged amino acids, letting it pass cell membranes and concentrate in the inner mitochondrial membrane. Binding cardiolipin stabilises the electron transport chain, improves ATP production and reduces the leakage of reactive oxygen species. In ageing and disease models cardiolipin becomes damaged, so the approach targets a common failure point.

What the research shows

• Preclinical studies showed improved heart, skeletal-muscle and kidney mitochondrial function in ageing and injury models.
• In Barth syndrome (TAZPOWER trial and open-label extension), long-term elamipretide was associated with improved walking distance and muscle strength.
• Trials in primary mitochondrial myopathy and heart failure produced mixed results.

SS-31 side effects

In clinical trials the most common side effects were injection-site reactions — redness, itching and pain, sometimes marked. Headache and dizziness were also reported.

UK legal status

Elamipretide is not licensed in the UK. Research-grade SS-31 is sold for laboratory use only.

More detail, including current UK research-vial prices: SS-31 UK guide. For the doses used in published studies and the reconstitution maths: SS-31 dosing in the literature.

References

1. Szeto HH. First-in-class cardiolipin-protective compound as a therapeutic agent to restore mitochondrial bioenergetics. Br J Pharmacol. 2014;171:2029–2050.
2. Thompson WR, et al. A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome. Genet Med. 2021;23:471–478.