SS-31
A daily shot that tunes up your mitochondria over 4 to 16 weeks. Steadier energy, not a buzz; the one longevity peptide with human trials.
What it is
SS-31 is for the person whose energy has gone flat in a way sleep does not fix: slower recovery, afternoons that drag, workouts that feel heavier than they should. It works inside the mitochondria, the parts of your cells that make energy, sealing the membrane so less energy leaks. Think of it as an oil change for the engine: a daily shot for 4 to 16 weeks, then 2 to 4 weeks off before the next run.
Who actually runs it: people over 40 doing a longevity stack, endurance athletes in a heavy block, and people coming back from a long illness or a stretch of burnout where everything feels like it costs more. It is the mitochondrial peptide with the strongest research footing, because under the name elamipretide it has been through human trials for rare mitochondrial and heart diseases and is FDA-approved, as Forzinity, for one of them. It is not a stimulant; if you want to feel something on day one, this is the wrong tool.
What you will notice, and when: nothing for the first week. Around week two or three, people report that the afternoon dip softens, that recovery between hard sessions is quicker, and that a long day leaves less of a hangover. Good at the end of the first month looks like steadier output, not higher peaks. A fair number of people feel nothing on a first run and still notice the difference when they stop; that is the honest spread. It will not fix energy that is really a sleep, thyroid or iron problem.
How people run it: 2 mg subQ once a day for 4 to 16 weeks, then 2 to 4 weeks off before the next run. The break is not because it stops working (the elamipretide trials dosed it daily for months); it is caution with a research product, and the weeks off show you what the run actually did. A 50 mg vial is 25 days at 2 mg, so a 4-week run takes just over one vial and a 16-week run about four and a half. Higher tiers of 5 and 10 mg are for coming back from a bad stretch, and they are expensive: the same vial is ten days at 5 mg and only five days at 10 mg, so even a 4-week run at the top tier is six vials, and if you go up, the cost argues for the short end of the run. Morning is the usual time, since a few people find evening doses keep them up. The mistake is running 10 mg because the vial allows it and the forum said so; most people get what they are going to get at 2 mg, and nothing shows the higher tiers do more for this use.
The evidence, once: SS-31 binds cardiolipin on the inner mitochondrial membrane and stabilizes it, improving energy output and reducing the free radicals that leak out, shown across many animal models of heart, kidney, muscle and aging. As elamipretide it has run human trials in primary mitochondrial myopathy, Barth syndrome, heart failure and dry macular degeneration, with mixed results: real signals, some missed primary endpoints. In September 2025 the FDA gave it accelerated approval as Forzinity for Barth syndrome, at 40 mg subQ once a day, based on improved muscle strength. That is far more human data than any other longevity peptide here, and it is still not approved for the way people use it.
When it is not worth it: if your tiredness has an obvious cause (bad sleep, low iron, low thyroid, too much training), fix that first, because SS-31 is a tune-up, not a repair. If you want the cheapest well-tolerated energy support, NAD+. If you want the 'gas pedal', MOTS-c. The framing we use is the useful one: MOTS-c is the pedal, NAD+ is the fuel, SS-31 makes the engine run efficiently. Run them together only if you have already run SS-31 alone and know what it does for you.
What people use it for
Energy and muscle in mitochondrial disease
Some evidenceAs elamipretide, SS-31 has been through randomized trials in people with primary mitochondrial myopathy and in Barth syndrome, a rare inherited heart-and-muscle disease. Early trials improved walking distance and fatigue; a larger myopathy trial missed its main endpoint, while the Barth syndrome data held up well enough for an FDA accelerated approval in 2025 (Forzinity). For a healthy person that means the mechanism works in humans, and the size of any benefit outside disease is unmeasured.
Heart and aging muscle
Some evidenceIn aged animals, SS-31 restored mitochondrial function in heart and skeletal muscle and reversed some age-related decline in exercise capacity within weeks. Small human heart-failure studies showed modest, short-term improvements in heart function. This is the basis for the longevity use, and it is animal-strong, human-modest.
Eyes
Early daysElamipretide has been tested in dry age-related macular degeneration, where mitochondrial failure in the retina is part of the disease. Signals on some vision measures were mixed. It is a reason to be interested in the compound's reach, not a reason for a healthy person to run it.
Everyday energy and recovery
Early daysWhat most people on this site actually want from it, better recovery and a softer afternoon dip, has not been studied in healthy people. Reports are consistent and modest, and the effect is usually noticed in week two or three rather than on day one.
How it works
- Used for energy and cellular health
- Targets the mitochondria directly
- In human trials under the name elamipretide
- Promising for energy-related conditions, still being studied
How people use it
Safety, in brief
Things people sometimes notice
- Redness or a small sore spot where you inject; the half-mL draw at the top tier is bigger than most peptides
- A few days of feeling slightly more tired or 'off' as you start, which usually resolves by week two
- Trouble falling asleep if you dose in the evening, for some
The full picture — stop signs and who should talk to a doctor first — is on the dosing guide.
Sources
The labels and studies behind this page. Each link opens the original on PubMed, DailyMed or ClinicalTrials.gov.
- Forzinity (elamipretide) prescribing information
- A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome, a genetic disorder of mitochondrial cardiolipin metabolism
- Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial
- Novel Mitochondria-Targeting Peptide in Heart Failure Treatment: A Randomized, Placebo-Controlled Trial of Elamipretide