MOTS-c vs SS-31
Both aim at the mitochondrion, but only one has been through randomized human trials, and SS-31's record is mostly misses while MOTS-c has never been tested in people.
Short answer
The clearest difference is regulatory. SS-31 is FDA-approved, and MOTS-c is not FDA-approved. SS-31 suits a reader who puts weight on FDA approval, though that approval does not cover every use it is marketed for, while MOTS-c is marketed for metabolism, endurance and longevity. On the evidence, MOTS-c has only preclinical or minimal evidence and SS-31 has human clinical data.
MOTS-c
A genuine mitochondrial-derived peptide with interesting rodent data on metabolism and exercise — but no human outcome trials.
Full MOTS-c evidence reviewSS-31
Elamipretide
A cardiolipin-binding peptide with a mostly disappointing trial history; elamipretide won a narrow, confirmation-pending accelerated FDA approval for Barth syndrome — not for the anti-aging use it's sold for.
Full SS-31 evidence reviewMOTS-c vs SS-31: head to head
- FDA status / approved use
MOTS-c
Not FDA-approved for any use; sold as a research-use-only injectableSS-31
FDA accelerated approval (Forzinity, 2025) for muscle strength in Barth syndrome only; investigational otherwise- Marketed for
MOTS-c
Metabolism, endurance, longevitySS-31
Mitochondrial function, longevity- Outcome areas
MOTS-c
Mitochondrial / cellular energy; Exercise performance / endurance; Longevity / lifespanSS-31
Mitochondrial / cellular energy; Longevity / lifespan- Evidence grade
MOTS-c
Preclinical / minimalSS-31
Clinical data- How it works
MOTS-c
Mitochondrial peptide targeting the folate-AICAR-AMPK energy-sensing pathwaySS-31
Binds cardiolipin in the inner mitochondrial membrane, supporting efficient energy production- Route and dosing
MOTS-c
InjectionSS-31
Subcutaneous injection, 40 mg once daily- Headline human result
MOTS-c
Not establishedSS-31
No benefit in the phase 3 MMPOWER-3 trial of 218 adults with mitochondrial myopathy; walk distance −3.2 meters vs placebo- Strongest evidence
MOTS-c
Lee, Cell Metab 2015. Little or no controlled human outcome data for the marketed useMOTS-c evidence reviewPubMed 25738459SS-31
Elamipretide (Barth), Genet Med 2024SS-31 evidence reviewPubMed 38602181- Key safety signal
MOTS-c
No long-term human safety data; research vials of unverified identity, dose, purity and sterilitySS-31
No established dosing or safety profile in healthy users- How it is obtained
MOTS-c
Sold gray-market as a research chemical; no approved or legitimately compounded human productSS-31
Prescription drug
| MOTS-c | SS-31 | |
|---|---|---|
| FDA status / approved use | Not FDA-approved for any use; sold as a research-use-only injectable | FDA accelerated approval (Forzinity, 2025) for muscle strength in Barth syndrome only; investigational otherwise |
| Marketed for | Metabolism, endurance, longevity | Mitochondrial function, longevity |
| Outcome areas | Mitochondrial / cellular energy; Exercise performance / endurance; Longevity / lifespan | Mitochondrial / cellular energy; Longevity / lifespan |
| Evidence grade | Preclinical / minimal | Clinical data |
| How it works | Mitochondrial peptide targeting the folate-AICAR-AMPK energy-sensing pathway | Binds cardiolipin in the inner mitochondrial membrane, supporting efficient energy production |
| Route and dosing | Injection | Subcutaneous injection, 40 mg once daily |
| Headline human result | Not established | No benefit in the phase 3 MMPOWER-3 trial of 218 adults with mitochondrial myopathy; walk distance −3.2 meters vs placebo |
| Strongest evidence | Lee, Cell Metab 2015. Little or no controlled human outcome data for the marketed useMOTS-c evidence reviewPubMed 25738459 | Elamipretide (Barth), Genet Med 2024SS-31 evidence reviewPubMed 38602181 |
| Key safety signal | No long-term human safety data; research vials of unverified identity, dose, purity and sterility | No established dosing or safety profile in healthy users |
| How it is obtained | Sold gray-market as a research chemical; no approved or legitimately compounded human product | Prescription drug |
marks a row where the two differ. “Not established” marks a cell the available evidence does not answer. Evidence grades come from our evidence matrix, which grades each molecule on the human data for the use it is marketed for.
- Clinical data:
- Tested in humans — but investigational, discontinued, or proven only on a surrogate marker (not the marketed outcome).
- Preclinical / minimal:
- Evidence is largely animal, in-vitro, or anecdotal. Little or no controlled human outcome data for the marketed use.
Our verdict
MOTS-c is preclinical: real mitochondrial-derived-peptide biology in rodents and cells, with no randomized human outcome trial behind the metabolism, performance, or longevity claims. SS-31 (elamipretide) is a different kind of unproven; it ran real trials and largely missed, including the Phase 3 MMPOWER-3 in primary mitochondrial myopathy, which did not meet either primary endpoint, before earning a narrow, confirmation-pending accelerated FDA approval for muscle strength in Barth syndrome. Neither has evidence of benefit in healthy people, and anything sold as MOTS-c, or as SS-31 outside that Barth syndrome approval, is unapproved research material.
MOTS-c fits if
MOTS-c is the more interesting read if you follow mitochondrial biology for its own sake and accept that every metabolic and exercise claim is extrapolated from mice.
SS-31 fits if
SS-31 is the one to study if you want to see an elegant mitochondrial mechanism actually put to randomized test, keeping in mind its only approval is for Barth syndrome, not aging.
MOTS-c vs SS-31: common questions
- Is SS-31 FDA-approved but MOTS-c not?
- Yes. SS-31 has FDA accelerated approval (Forzinity, 2025) for muscle strength in Barth syndrome only; investigational otherwise. MOTS-c is not FDA-approved for any use; sold as a research-use-only injectable.
- Which has stronger human evidence, MOTS-c or SS-31?
- SS-31. It has human clinical data (key source: Elamipretide (Barth), Genet Med 2024), while MOTS-c has only preclinical or minimal evidence (key source: Lee, Cell Metab 2015).
- What are the main safety concerns with MOTS-c and SS-31?
- MOTS-c has no long-term human safety data; research vials of unverified identity, dose, purity and sterility. SS-31 has no established dosing or safety profile in healthy users.
Key studies behind each
MOTS-c
- Lee C, Zeng J, Drew BG, et al. (2015). The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab. PubMed 25738459
- Kim SJ, Miller B, Mehta HH, et al. (2019). The mitochondrial-derived peptide MOTS-c is a regulator of plasma metabolites and enhances insulin sensitivity. Physiol Rep. PubMed 31293078
- Reynolds JC, Lai RW, Woodhead JST, et al. (2021). MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nat Commun. PubMed 33473109
- Kim SJ, Miller B, Kumagai H, et al. (2021). Mitochondrial-derived peptides in aging and age-related diseases. GeroScience. PubMed 32910336
SS-31
- Szeto HH, Liu S. (2018). Cardiolipin-targeted peptides rejuvenate mitochondrial function, remodel mitochondria, and promote tissue regeneration during aging. Arch Biochem Biophys. PubMed 30359579
- Karaa A, Bertini E, Carelli V, Cohen BH, et al. (2023). Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial. Neurology. PubMed 37268435
- Karaa A, Haas R, Goldstein A, Vockley J, et al. (2018). Randomized dose-escalation trial of elamipretide in adults with primary mitochondrial myopathy. Neurology. PubMed 29500292
- Reid Thompson W, Hornby B, Manuel R, Bradley E, et al. (2021). 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. Genet Med. PubMed 33077895
The full evidence reviews
- MOTS-c peptide: benefits, side effects and what the evidence shows
Real mitochondrial biology, absent human evidence: a genuine mitochondrial-derived peptide with interesting rodent data on metabolism and exercise, but no human outcome trials. Promising biology, not a proven therapeutic.
Updated October 2026
- SS-31 peptide (elamipretide): benefits, evidence and approval status
An elegant mitochondrial mechanism meets a hard clinical record: a cardiolipin-binding peptide with a failed myopathy trial and a narrow, confirmation-pending Barth syndrome approval. A straight read.
Updated October 2026