MOTS-c vs SS-31
Two mitochondrial peptides, usually run together. What does each one actually do?
Reviewed by the amino101 editorial team. , first published .
MOTS-c and SS-31 are the two peptides sold for mitochondrial health, and they approach the mitochondria from opposite directions. MOTS-c is a 16 amino acid peptide encoded in mitochondrial DNA that acts as a metabolic signal: it raises AMPK activity, which increases glucose uptake and fat oxidation in muscle in a way that resembles exercise. SS-31 is a four amino acid synthetic peptide that concentrates in the inner mitochondrial membrane and binds cardiolipin, stabilizing the electron transport chain so it produces ATP more efficiently with less leak. SS-31 is elamipretide, a clinical stage drug with a substantial human trial history including heart failure, mitochondrial myopathy and Barth syndrome, where it received FDA accelerated approval in 2025 as Forzinity. MOTS-c has no human trial of the native peptide; a modified analog, CB4211, completed phase 1. Research grade SS-31 is not the pharmaceutical product. Both are prohibited by WADA. This is an educational comparison of two compounds with very different amounts of human data.
| MOTS-c | SS-31 | |
|---|---|---|
| Typical dosage | 5 to 10 mg | 5 to 10 mg |
| Frequency | two to three times per week | once daily |
| Route | Subcutaneous, Intramuscular | Subcutaneous, Intravenous |
| Half-life | Not well characterized; likely well under an hour in plasma | Roughly 2 to 4 hours in plasma (clinical data) |
| Cycle | 4 to 8 weeks | 4 to 8 weeks |
| Research level | Limited research | Extensively studied |
| Human trials | Small pilots | Approved drug |
| Status | Investigational, not FDA approved; an analog reached phase 1 trials | Clinical-stage drug (elamipretide) with an FDA accelerated approval for Barth syndrome; research-grade SS-31 is not that product |
| Effects timeline | energy and workout endurance reports over 2 to 4 weeks, body composition changes at 6 to 8 weeks if they happen at all | clinical endpoints were measured over weeks to months; community reports of better energy within 1 to 2 weeks are unverified |
Key differences
MOTS-c vs SS-31 dosage
Dosage patterns reported in research and community protocols, by goal. Taken from each compound page. Not a prescription.
| Goal | Dosage | Frequency |
|---|---|---|
| Conservative start | 5 mg | twice weekly |
| Common community protocol | 10 mg | twice weekly |
| Loading phase (community) | 10 mg | three times weekly |
| Training day only | 5 to 10 mg | on training days, up to three per week |
| Goal | Dosage | Frequency |
|---|---|---|
| Conservative community protocol | 5 mg | once daily |
| Common community protocol | 10 mg | once daily |
| Clinical trial range | 20 to 40 mg | once daily |
| Approved Barth syndrome dose | 40 mg | once daily |
Convert any of these to syringe units in the dosage calculator.
Side effects compared
- ▲Injection site redness, itching or small lumps
- ▲Transient fatigue or flushing after a dose
- ▲Temporary drops in blood glucose
- ▲Headache
- ▲Mild nausea
- ▲Injection site redness, itching, swelling or small lumps
- ▲Headache
- ▲Dizziness
- ▲Nausea
- ▲Fatigue in some people, the opposite of what they expected
Which should you choose?
MOTS-c is the fit for someone whose interest is metabolic: insulin sensitivity, endurance, fat oxidation, and the exercise mimetic idea. Reported protocols are 5 to 10 mg two to three times weekly, often before training. Go in knowing that the human effective dose is unknown and the mouse data used far more per kilogram. Anyone on glucose lowering drugs should watch for dips.
SS-31 is the fit for someone who wants the compound with an actual clinical record, or who is interested in mitochondrial protection rather than metabolic signaling. Community protocols report 5 to 10 mg once daily subcutaneously, well under the 40 mg clinical dose. Rotate injection sites, since reactions were the main trial complaint, and remember that research grade product is not elamipretide.
SS-31 is the one with real human evidence, and also the one whose biggest trial failed, which is a useful corrective to the marketing around both. In Barth syndrome, a rare cardiolipin disorder, elamipretide earned accelerated approval. In primary mitochondrial myopathy, the large MMPOWER-3 trial did not beat placebo on its walking endpoint. For a healthy adult hoping for more energy, that record means the benefit is not established, and community doses of 5 to 10 mg are a fraction of the 40 mg used clinically. MOTS-c has the more interesting story, exercise mimicry and doubled running capacity in old mice, but no human trial of the native peptide, and mouse doses per kilogram are far above anything people inject. If forced to pick: SS-31 for anyone with a reason to care about mitochondrial stress, MOTS-c for someone chasing endurance and metabolic effects who accepts rodent only evidence. Most people do not pick; the two are run together, as described in the MOTS-c and SS-31 stack.
Stacking: Usually run together: SS-31 daily and MOTS-c two or three times weekly, often both in the morning or before training. NAD+ is the common third addition.
MOTS-c is a 16-amino-acid peptide encoded in mitochondrial DNA that acts as a metabolic signal, improving insulin sensitivity and exercise capacity in mice. People use it for fat loss, endurance, and metabolic aging.
SS-31 is a four-amino-acid peptide that concentrates in the inner mitochondrial membrane and binds cardiolipin, stabilizing energy production. As elamipretide it has been through multiple human trials, most notably for the rare mitochondrial disease Barth syndrome.
MOTS-c vs SS-31: frequently asked
Can you take MOTS-c and SS-31 together?
Yes, and that is how most people use them. MOTS-c drives metabolic signaling while SS-31 protects the machinery, so the mechanisms are complementary rather than overlapping. A typical pattern is SS-31 daily and MOTS-c two or three times weekly; see the MOTS-c and SS-31 stack. No trial has tested the pair.
Is SS-31 the same as elamipretide?
The molecule is the same. Elamipretide is the pharmaceutical form developed by Stealth BioTherapeutics and approved as Forzinity for Barth syndrome in 2025. Research grade SS-31 sold online is not that product and has no quality assurance behind it.
Which is better for energy, MOTS-c or SS-31?
Neither has a trial showing improved energy in healthy adults. SS-31's largest trial in mitochondrial myopathy missed its primary endpoint, and MOTS-c's energy data is from mice. Community reports favor both, at doses with no established effect, so placebo is a reasonable explanation.
Does MOTS-c help with fat loss?
In mice it prevented diet induced obesity and improved insulin sensitivity. There is no human fat loss trial. Some people add it during GLP-1 treatment hoping to preserve muscle and exercise capacity, without any combined data. It is not a weight loss drug.
What are the side effects of SS-31 and MOTS-c?
For both, injection site reactions are the main complaint: redness, itching, small lumps. SS-31 trials also listed headache, dizziness and nausea. MOTS-c users report transient fatigue or flushing and occasional blood glucose dips. Long term safety outside clinical monitoring is unknown for either.
How much SS-31 did the clinical trials use?
40 mg subcutaneously once daily in the Barth syndrome program, with 20 to 40 mg across other trials. Community protocols cluster at 5 to 10 mg daily, which is a fraction of the studied dose and one reason reported effects should be read cautiously.
Related reading
Sources
- The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metabolism, 2015
- MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nature Communications, 2021
- A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome. Genetics in Medicine, 2021
- Efficacy and safety of elamipretide in individuals with primary mitochondrial myopathy: the MMPOWER-3 randomized clinical trial. Neurology, 2023