Extensive human trial data for the pharmaceutical form (elamipretide); research-grade SS-31 is not that product
SS-31 is the research name for elamipretide, a mitochondria-targeting tetrapeptide that Stealth BioTherapeutics has taken through multiple randomised trials in heart failure, primary mitochondrial myopathy and Barth syndrome. Its adverse-effect profile is therefore unusually well characterised for a compound sold by research vendors: injection-site reactions dominate. The efficacy record is mixed, which matters when weighing any risk.
Research-use information only. Research-grade SS-31 is not an approved medicine; where trial or label figures appear below they belong to the pharmaceutical product studied, not to any research vial. This page does not give dosing or medical advice.
Every rate carries its source. Where no source exists, no rate is printed.
| Effect | Rate (sourced) | Detail | Source |
|---|---|---|---|
| Injection-site reactions (erythema, pain, pruritus) | not quantified | The most frequent adverse event across subcutaneous elamipretide trials; generally mild and reported at high frequency in daily-injection studies. | Daubert et al. 2017 (PROGRESS-HF); Stealth BioTherapeutics trial reports |
| Serious adverse events | not quantified | No consistent drug-related serious adverse-event signal has been reported across the published trials. | Daubert et al. 2017; Szeto 2014 (review) |
Regulatory status: Elamipretide received FDA accelerated approval for Barth syndrome in 2025 (marketed as Forzinity); it is not approved for any other indication. Research-grade SS-31 is not the approved product.
Everything above describes SS-31 the molecule. The risk specific to a research vial is different: it may not contain SS-31 at the labelled amount, and it may contain what the synthesis left behind. Identity (mass spectrometry), purity (HPLC), measured net content and an endotoxin result are the four lines on a certificate that bear on adverse effects, and only a certificate you can check at the laboratory tells you any of them. This is what we have verified for SS-31 so far.
5 of the 77 vendors on our scoreboard list SS-31 with a price we read on the product page (23 Sept 2026–23 Sept 2026). Of those, 5 name their testing laboratory, 4 publish certificates that resolve on the lab's own site, and 5 publish measured milligrams against the label. The full ranking, with every dated price, is on Best SS-31 Vendors.
| Vendor | Rubric | Lab named | Price read |
|---|---|---|---|
| Peptide Giantspartner | 10/10 | Janoshik Analytical · Vanguard Laboratory | $49.99 · 10mg · 23 Sept 2026 |
| Everest Peptides | 8/10 | Freedom Diagnostics | $37.49 · 10mg · 23 Sept 2026 |
| PS Peptidespartner | 8/10 | North American Diagnostics | $64.99 · 10mg · 23 Sept 2026 |
| Puratek Peptidespartner | 7/10 | ILS Laboratories (on certificates) · page credits Freedom Diagnostics | $74.95 · 30mg · 23 Sept 2026 |
| Arizen BioLabspartner | 6/10 | Janoshik (on certificates) | $125.99 · 50mg · 23 Sept 2026 |
None yet for SS-31 specifically. The COA library holds the certificates we have read for each vendor on other compounds, which is the next best signal of how that vendor documents a lot.
In the published elamipretide trials, injection-site reactions — redness, pain, itching — were by far the most common, and were usually mild. No consistent serious adverse-event signal has been reported. Those data come from the pharmaceutical product given under trial conditions, not from research vials.
Elamipretide has a narrow 2025 FDA accelerated approval for Barth syndrome, a rare mitochondrial disease. It is not approved for heart failure, mitochondrial myopathy, ageing or performance, and research-grade SS-31 is not the approved product.