Bottom line: A mitochondrial peptide, FDA-approved for one rare disease only. The anti-aging use everyone wants it for is unproven. A read, not a buy.
Safety at a glance
- Status: FDA-approved as Forzinity for Barth syndrome only; all other uses are research.
- Evidence: Approved for Barth syndrome only; other uses investigational (mixed trials).
- Do not use if: you are using it off-label for anti-aging expecting a proven benefit - that use is unproven; discuss with a doctor.
- Not medical advice - decide this with a licensed physician.
What it does - plain English
SS-31 (its drug name is elamipretide) is a tiny four-amino-acid peptide with one unusual trick: it goes straight to your mitochondria, the structures inside every cell that turn food and oxygen into usable energy. It concentrates in the inner mitochondrial membrane and binds a fat molecule there called cardiolipin, which holds the energy-producing machinery in the right shape.
When cardiolipin is damaged - by age, disease, or oxidative stress - the power plant gets leaky and inefficient. SS-31 is designed to stabilize it, cut the damaging reactive oxygen species (cellular "exhaust"), and restore cleaner energy production. In plain English: it props up the cell's power plants.
That mechanism is why it gets talked about for aging, heart failure, and neurodegeneration - all conditions where mitochondria break down. The mechanism is real and well-studied. Whether it translates into those benefits in healthy people is the open question.
Status
Watch. A real, approved drug - for the wrong reason if you're chasing longevity. This is the honest crux of SS-31, so read it carefully.
Elamipretide is FDA-approved, but only for Barth syndrome, a rare inherited mitochondrial disease that affects roughly one in a million people. It is the longevity, heart-failure, eye-disease, and brain-aging uses - the ones that make it interesting to biohackers - that remain investigational or research-only. And several of the bigger trials in those other conditions missed their main goals before the Barth approval came through. So the track record is mixed: a clear win in one rare disease, unproven everywhere else.
Legal status
The FDA granted accelerated approval in September 2025, and elamipretide is sold by Stealth BioTherapeutics under the brand name Forzinity for Barth syndrome in patients weighing at least 30 kg. That is its only approved indication.
Because it's an orphan drug for a rare disease, you will not get a Forzinity prescription for general anti-aging. What you'll find instead is "SS-31" sold by research peptide vendors labeled "for research purposes only, not for human consumption" - the same unregulated gray zone every research peptide lives in. The molecule may be the same; the oversight, purity guarantees, and dosing guidance are not.
Side effects and the honest caveat
In the Barth trials the most common issue was injection-site reactions. The bigger caveat isn't a specific side effect - it's that long-term safety in healthy adults using it off-label for aging simply hasn't been studied. You would be an early human data point. The mechanism is elegant; the human longevity evidence is not there yet.
New to peptides? Start with the foundations ->
The trials worth knowing
TAZPOWER - the approval trial
Pharmacy Times - FDA grants accelerated approval to elamipretide for Barth syndrome
The randomized, placebo-controlled trial plus its long open-label extension showed improvements in muscle strength, fatigue, and cardiac function in Barth syndrome patients. The accelerated approval rested on improved knee-extensor muscle strength - an intermediate marker, not a longevity endpoint.
The first drug to directly target mitochondria
Johns Hopkins Hub - FDA approves first drug to treat a mitochondrial disorder
Useful context on why the approval is a scientific milestone: it is the first medicine cleared to act directly on mitochondria. That is exactly why the longevity world is excited - and exactly why it's worth separating the proven Barth use from the unproven aging hopes.
Last reviewed · 2026·06·04 · Status reviewed weekly