Compound guide · Tier A
SS-31
The longevity crowd were buying this for years while it was unapproved. It became an approved medicine in September 2025, for a disease almost none of them have.
The short answer
SS-31 is the rarest thing in this catalogue: a compound that graduated. Elamipretide spent years as an investigational molecule bought as research material on the strength of its mechanism, and in September 2025 it earned accelerated approval for Barth syndrome. That is a real achievement and it is not a general endorsement. The approval covers an ultra rare genetic mitochondrial disorder, rests on an intermediate strength endpoint rather than a hard clinical outcome, and arrived only after FDA reviewers raised effectiveness concerns and an advisory committee split 10 to 6 in favour. Nothing in that record speaks to healthy adults taking it for ageing, energy or performance, which is why almost all of it is actually bought.
At a glance
| Class | Mitochondria targeting tetrapeptide, cardiolipin binding |
| Developer | Stealth BioTherapeutics |
| Sold as | Forzinity (elamipretide) |
| Regulatory status | Approved, and recently. The FDA granted accelerated approval to elamipretide on 19 September 2025, marketed as Forzinity, to improve muscle strength in adult and paediatric patients weighing over 30 kg with Barth syndrome. It is the first therapy targeting mitochondria directly to reach approval. Read the qualifiers carefully: this is accelerated approval, granted on knee extensor strength as an intermediate endpoint, for an ultra rare inherited disease affecting a very small number of people. |
| Compounding status | Elamipretide is now an approved drug product, which changes the picture that existed before September 2025. Material sold as research grade SS-31 is not Forzinity, has not been through the manufacturing controls behind an approved product, and carries none of its labelling or monitoring. |
| Anti-doping | Not specifically named on the prohibited list. Use outside an approved therapeutic context in tested sport would still need to be assessed against the list as published each year. |
| Our evidence tier | Tier A. Approved medicine |
What it is
SS-31, now elamipretide, is a small tetrapeptide that concentrates in the inner mitochondrial membrane and binds cardiolipin, a lipid essential to the structure of that membrane and to the function of the electron transport chain. The mechanism is structural rather than antioxidant: it is described as stabilising the machinery rather than mopping up radicals after the fact. That is a genuinely novel mode of action and it is the reason the approval attracted attention beyond the Barth syndrome community.
Who it is for, and who actually takes it
The approved population is adults and children over 30 kg with Barth syndrome, an X linked genetic disorder affecting cardiolipin remodelling, which causes cardiomyopathy, skeletal muscle weakness and neutropenia. It affects a very small number of people worldwide.
It is bought overwhelmingly by people with no mitochondrial disease at all, for energy, ageing, endurance and general mitochondrial health. Those uses have no controlled human evidence, and the approval that makes the compound sound validated was granted for something else entirely.
What the research shows
The approval rests on a knee extensor strength endpoint in a very small ultra rare disease population. Charting a single intermediate endpoint from a tiny cohort beside our large trial charts would imply a comparability of evidence that does not exist.
Dosing
| Stage | Dose |
|---|---|
| Approved indication | Barth syndrome, to improve muscle strength |
| Approved population | Adults and paediatric patients weighing over 30 kg |
| Route | Subcutaneous injection |
| Basis of approval | Accelerated approval on knee extensor strength as an intermediate endpoint |
| Date of approval | 19 September 2025, FDA |
This records what the regulator approved and on what basis, because that is public record. It is not a recommendation and it does not transfer to anyone without Barth syndrome. Accelerated approval also carries an obligation to confirm benefit in further study, so this is a licence granted on promising intermediate evidence rather than a settled question. We publish no reconstitution guidance.
What happens when you come off it
There is no published discontinuation data relevant to people without Barth syndrome, because they were not studied. Within the approved population, the drug is a treatment for an ongoing genetic condition rather than a course, and the accelerated approval framework means long term outcome data is still being gathered.
What it is being studied for
| Area | Stage of evidence |
|---|---|
| Barth syndrome, muscle strength | Approved, accelerated approval September 2025 |
| Primary mitochondrial myopathy | Investigated, did not lead to approval in that indication |
| Age related mitochondrial decline in healthy adults | No controlled human evidence |
| Endurance or athletic performance | No controlled human trial |
| Dry age related macular degeneration and other eye disease | Investigated, not approved |
The gap between row one and row three is the entire story of this compound. An approval in an ultra rare inherited disease is being read by the wellness market as validation of a general mitochondrial benefit. It is not that, and the FDA did not say it was.
Common myths
SS-31 is FDA approved, so the mitochondrial benefits are proven.
It is approved to improve muscle strength in Barth syndrome, on accelerated approval using an intermediate endpoint. That is a specific finding in a specific genetic disease. It establishes nothing about mitochondrial function in healthy adults, and the FDA has not claimed otherwise.
It is an antioxidant, so it protects your cells.
The mechanism is not radical scavenging. Elamipretide binds cardiolipin and stabilises the inner mitochondrial membrane, which is a structural action. Describing it as an antioxidant misstates the pharmacology and imports a set of claims that do not belong to it.
The approval was straightforward, so the evidence must be strong.
It was not straightforward. FDA reviewers raised concerns about effectiveness, the advisory committee voted 10 to 6 rather than unanimously, the review was extended and then missed its action date over a manufacturing inspection, and approval finally came through the accelerated pathway on an intermediate endpoint. That is a licence, and it is a licence granted with visible reservations.
Research grade SS-31 is the same as Forzinity.
It may be the same molecule. Forzinity is a manufactured, released, labelled product with a regulator behind it and a confirmatory evidence obligation attached. A research vial is powder with a purity certificate, which addresses identity and content and says nothing about sterility or endotoxin.
Verifying a purchase
SS-31 is a very small peptide at 639.8 Da, which puts it within easy reach of synthesis and therefore of substitution. Mass spectrometry confirming 639.8 Da is the check that matters, and CAS 736992-21-5 should match. Watch the content figure as well as the purity figure: the published lot report for this vendor measured 11.17 mg against a 10 mg label, an overfill of nearly 12%, which is a deviation worth noticing on any compound sold by weight.
The general method is set out in our guide to reading a certificate of analysis, which covers the eleven checks that apply to any compound. The points above are the ones specific to SS-31.
Caveats and safety
The safety data that exists was gathered in Barth syndrome trials in a monitored population, and the accelerated approval pathway means the full benefit and risk picture is still being established. There is no safety database for healthy adults taking elamipretide for ageing or performance, and the novelty of the mechanism cuts both ways: a molecule that concentrates a thousandfold in the inner mitochondrial membrane is not obviously inert at the wrong dose.
Where to get it
Where to get it
CertaPeptides Romania, EU. Volume discounts at 3+, 5+ and 10+ units.
| Vial | Price |
|---|---|
| 10 mg | €47.99 |
| 50 mg | €136.99 |
Stated purity. ≥98% stated batch specification. Published lot report #212156 returned 99.84% on a 10 mg vial, with 11.17 mg measured against a 10 mg label, which is 111.7% of the stated content.
Documentation. Selected lots independently tested by Janoshik Analytical (Czech Republic), HPLC plus mass spectrometry, reports searchable on the Janoshik public portal and at certapeptides.com/verify.
SS-31 is sold as laboratory research material. The vendor states it is not for human consumption and that it is not approved by the FDA, the EMA or any other regulator for use in humans or animals. Read the evidence tier at the top of this page before the price.
View SS-31 at CertaPeptidesAffiliate link. We earn a commission if you buy, at no extra cost to you. It does not change a word of the assessment above. Every product we have priced, in one list.
Sources
- Drugs@FDA record for elamipretide (Forzinity)
- Stealth BioTherapeutics regulatory announcements
- FDA approves first mitochondrial disease therapy, UMDF
- Registered elamipretide trials, ClinicalTrials.gov
Related compounds
Disclosure. PeptoPurity is an affiliate of CertaPeptides and earns a commission on qualifying purchases made through the vendor link on this page, at no additional cost to you. That relationship does not set the evidence tier, alter the verdict, or change a word of the assessment. Our Tier C and Tier D pages carry the same links as our Tier A pages, with the same conclusions we would publish if we earned nothing. Where the registered, prescribed route is the better option, we say so on the page that would otherwise pay us.
Scope. This is an evidence review, not medical advice. Where an approved label schedule is reproduced it is a record of what a regulator has published about a licensed medicine, not a recommendation and not a schedule for anyone to follow unsupervised. For unapproved compounds we report only the doses used in published studies, attributed to those studies, and we publish no protocols and no reconstitution guidance for any compound. Regulatory status differs between countries and changes over time. Material sold for laboratory research is not approved for human use. Decisions about treatment belong with a qualified prescriber.