SS-31

weak data

Also seen as: elamipretide, MTP-131, Elamipretide, Bendavia

The Dose Guy’s verdict

Aug 29, 2026
4 sources

SS-31 has a strong origin story: a peptide that parks itself on the inner mitochondrial membrane and tunes up the electron transport chain. The problem is the scoreboard. Trial after trial has hit interesting secondary endpoints while missing the primary one it was designed to prove. The FDA gave it accelerated approval for Barth syndrome on open-label data, which is a foothold, not a verdict. If you are chasing mitochondrial recovery or anti-aging, the mechanism is genuinely interesting, but one infusion in older adults raised mitochondrial ATP immediately and then faded by day seven. That is the honest shape of the human evidence so far.

Would I take it?Caution. The mechanism is real, the scoreboard is not.

What it is

SS-31 is a four-amino-acid peptide engineered to cross into mitochondria and bind cardiolipin, a lipid that holds the respiratory chain together. By stabilizing those complexes, it improves electron flow and dials down the reactive oxygen species that damaged mitochondria leak.

The appeal for the biohacking crowd is obvious: if aging is partly a mitochondrial story, a peptide that services the engine is the dream drug. And the preclinical data is strong, mice, dogs, cell models, all looking good. The trouble starts when you move to humans. SS-31 has been through more clinical trials than most peptides here, and the pattern is the same each time: the mechanism lights up on imaging or secondaries, but the primary endpoint does not move. For soft-tissue healing or gut repair, BPC-157 and TB-500 are the established starting points. SS-31 is a different bet: that servicing your mitochondria pays dividends that broader healing peptides do not.

What the research shows

More human trial data than most peptides here, and a frustrating track record with it:

MMPOWER-3, the phase 3 in primary mitochondrial myopathy: the week-24 placebo-adjusted 6-minute walk difference was -3.2 m on 40 mg daily, 95% CI -18.7 to 12.3, p=0.69. A clean miss.NMD 2023 · phase 3 · n=218

In the TAZPOWER open-label extension for Barth syndrome, 8 of 10 entrants reached week 168 and cumulative 6-minute walk improvement was 96.1 m, p=0.003. Unblinded, but enough for accelerated approval.2024 · open-label · n=10

In 39 older adults with poorly functioning mitochondria, a single elamipretide infusion raised muscle mitochondrial ATPmax versus placebo immediately, p=0.045, but the effect was gone by day 7, and hand-muscle fatigue resistance did not budge. The closest thing to an anti-aging receipt, and it faded in a week.2021 · RCT · n=39

ReCLAIM-2, in dry AMD with geographic atrophy: no significant benefit on low-luminance visual acuity or atrophy area at 48 weeks, but 43% less progression of ellipsoid-zone loss at a nominal p=0.0034. The now-familiar pattern.JAMA Ophthalmol 2024 · phase 2 · n=176

Realistic protocols

The clinical trials used 40 mg daily subcutaneous, and that is the reference dose. In the longevity community, most people start lower, around 5 to 10 mg per day, and assess over weeks before moving up. The reasoning is straightforward: the mechanism is about restoring mitochondrial efficiency, not overwhelming it, and the clinical safety data does not extend far beyond the trial populations.

Expect injection-site reactions. In the crossover trial, 80% of participants on elamipretide had them, mostly mild redness and discomfort. Rotate sites, and know that a red, itchy welt the day after is normal, not a sign something went wrong. There is no established cycling protocol. Some people run it in defined courses of 8 to 12 weeks, others keep it continuous. The honest answer is that nobody knows the optimal duration for the anti-aging use case, because no trial has tested it.

Start5–10 mg/daySub-q. Lower than trial dose, where most community users begin.

Full40 mg/dayTrial dose. Assess tolerability before pushing here.

Duration8–12 weeksA defined course. No long-term protocol data exists for the anti-aging use.

Side effects

No serious adverse events in the dedicated elamipretide trials, but injection-site reactions are the norm, not the exception:

commonInjection-site reactions in up to 80% of trial participants, mostly mild redness and discomfort that fades. Rotate sites.

monitorA meta-analysis of 19 mitochondrial-antioxidant studies covering 884 participants found no serious adverse-event signal overall, while subcutaneous elamipretide specifically increased mild-to-moderate injection-site events.

unknownNo long-term safety data for the anti-aging or biohacking use case. The trials studied sick populations for defined periods, not healthy people running it indefinitely.