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Comparison

MOTS-c vs SS-31

Both are mitochondrial & longevity, so the meaningful differences are in kinetics, evidence and regulatory status.

On published evidence alone, SS-31 is the better documented of the two (clinical trials). That is a statement about the state of the literature, not a recommendation.

MOTS-c SS-31
Class Mitochondrial & longevity Mitochondrial & longevity
Evidence Preliminary human Clinical trials
Human trials ~3 ~15
Half-life ~1-2 hours ~2-4 hours
Reported range 5-10 mg 40-60 mg
Frequency 2-3x weekly Once daily
Routes Subcutaneous, Intramuscular Subcutaneous
FDA approved No Yes
Research use only Yes No
Banned in sport No No
Studied for Metabolic health research, Insulin sensitivity, Exercise capacity research, Longevity Primary mitochondrial myopathy, Barth syndrome, Age-related muscle decline research
Reported side effects Injection-site reactions, Transient fatigue, Headache Injection-site reactions, Headache, Nausea, Dizziness

MOTS-c

MOTS-c is a 16-amino-acid peptide encoded within the mitochondrial 12S rRNA gene rather than in nuclear DNA, which makes it unusual among signalling peptides. It regulates the folate-methionine cycle, leading to accumulation of AICAR and consequent AMPK activation, shifting metabolism toward glucose uptake and fatty acid oxidation. Exercise raises endogenous MOTS-c, and levels fall with age, which is the basis of both the exercise-mimetic framing and the longevity interest. Human trial data is limited.

SS-31

SS-31 is a cell-permeable tetrapeptide that concentrates in the inner mitochondrial membrane, where it binds cardiolipin, the phospholipid essential to cristae structure and electron transport chain organisation. By stabilising cardiolipin interactions it improves respiratory efficiency and reduces reactive oxygen species generation at source rather than scavenging them afterwards. It is among the most clinically advanced compounds on this site, with phase III programmes in primary mitochondrial myopathy and Barth syndrome, though headline endpoints have been mixed.

MOTS-c vs SS-31: common questions

What is the difference between MOTS-c and SS-31?

Both are mitochondrial & longevity. MOTS-c: A mitochondria-encoded peptide that acts as an exercise mimetic through AMPK, and one of the better-characterised mitochondrial-derived peptides. SS-31: A cardiolipin-binding tetrapeptide that has been through multiple phase III trials in mitochondrial disease.

Which has stronger evidence, MOTS-c or SS-31?

SS-31 has the stronger evidence base (clinical trials, about 15 human studies) compared with MOTS-c (preliminary human).

Are MOTS-c and SS-31 FDA approved?

Only SS-31 is FDA approved (Barth syndrome, to improve muscle strength in patients weighing at least 30 kg (Forzinity, accelerated approval September 2025)). MOTS-c is not approved for any indication.

References

Regulatory and primary sources

  1. PubChem compound record (CID 146675088) ↗ · structure, identifiers, synonyms
  2. FDA: Unapproved drugs and "research use only" products ↗ · regulatory status of non-approved products
  3. PubChem compound record (CID 11764719) ↗ · structure, identifiers, synonyms
  4. DailyMed: FDA-approved labeling for SS-31 ↗ · indications, dosing, warnings as approved
  5. FDA Drugs@FDA database ↗ · approval history
  6. CAS Registry Number 736992-21-5 ↗ · chemical identity

Published literature

  1. Zhang Z, Chen D, Du K, et al.. MOTS-c: A potential anti-pulmonary fibrosis factor derived by mitochondria.Mitochondrion 2023.PubMed 37307934 · doi:10.1016/j.mito.2023.06.002
  2. Mohtashami Z, Singh MK, Salimiaghdam N, et al.. MOTS-c, the Most Recent Mitochondrial Derived Peptide in Human Aging and Age-Related Diseases.Int J Mol Sci 2022.PubMed 36233287 · doi:10.3390/ijms231911991
  3. Amado CA, Agüero J, García-Unzueta M, et al.. MOTS-c: How a secreted mitochondrial microprotein may become a potential treatment for inflammatory lung diseases.J Transl Med 2026.PubMed 42243958 · doi:10.1186/s12967-026-08398-2
  4. Lee C, Kim KH, Cohen P. MOTS-c: A novel mitochondrial-derived peptide regulating muscle and fat metabolism.Free Radic Biol Med 2016.PubMed 27216708 · doi:10.1016/j.freeradbiomed.2016.05.015
  5. Zheng Y, Wei Z, Wang T. MOTS-c: A promising mitochondrial-derived peptide for therapeutic exploitation.Front Endocrinol (Lausanne) 2023.PubMed 36761202 · doi:10.3389/fendo.2023.1120533
  6. Mendelsohn AR, Larrick JW. Mitochondrial-Derived Peptides Exacerbate Senescence.Rejuvenation Res 2018.PubMed 30058454 · doi:10.1089/rej.2018.2114
  7. Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance.Sports Med 2026.PubMed 41966639 · doi:10.1007/s40279-026-02437-0
  8. Cuyàs E, Verdura S, Martin-Castillo B, et al.. Circulating levels of MOTS-c in patients with breast cancer treated with metformin.Aging (Albany NY) 2022.PubMed 36490309 · doi:10.18632/aging.204423
  9. Nashine S. Potential Therapeutic Candidates for Age-Related Macular Degeneration (AMD).Cells 2021.PubMed 34572131 · doi:10.3390/cells10092483
  10. Shirley M. Elamipretide: First Approval.Drugs 2026.PubMed 41335372 · doi:10.1007/s40265-025-02269-8
  11. Obi C, Smith AT, Hughes GJ, et al.. Targeting mitochondrial dysfunction with elamipretide.Heart Fail Rev 2022.PubMed 35037146 · doi:10.1007/s10741-021-10199-2
  12. Rowe LW, Akotoye C, Harris A, et al.. Beyond the injection: delivery systems reshaping retinal disease management.Expert Opin Pharmacother 2025.PubMed 40319468 · doi:10.1080/14656566.2025.2496424
  13. Tung C, Varzideh F, Farroni E, et al.. Elamipretide: A Review of Its Structure, Mechanism of Action, and Therapeutic Potential.Int J Mol Sci 2025.PubMed 39940712 · doi:10.3390/ijms26030944
  14. Pavlović N, Križanac M, Kumrić M, et al.. Mitochondrial Dysfunction: The Silent Catalyst of Kidney Disease Progression.Cells 2025.PubMed 40497970 · doi:10.3390/cells14110794
  15. de Barcelos IP, Emmanuele V, Hirano M. Advances in primary mitochondrial myopathies.Curr Opin Neurol 2019.PubMed 31408013 · doi:10.1097/WCO.0000000000000743

Literature retrieved from PubMed on October 16, 2026, favouring human studies and reviews. Numbered markers in the text show which paper supports which statement; uncited entries are background reading.

Read this first This page compares published reference data. It is not medical advice and not a recommendation to use either compound. Several compounds documented on this site are not approved for human use.