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SS-31 vs MOTS-c: What the Research Shows

SS-31 and MOTS-c side by side: what they are, how they are regulated and what is still unknown.

Medically reviewed by Juan Pablo Frías, MD · · DisclosureUpdated
Mitochondria-targeting peptideFDA accelerated approval for Barth syndrome (Sep 2025)SS-31SS-31 (elamipretide), a mitochondria-targeting peptide with accelerated FDA approval for Barth syndrome; a phase 3 trial in primary mitochondrial myopathy did not meet its primary endpoints.[5]Longevity+374% searchesMitochondrial-derived peptidePCAC voted 7–5 for 503A (Jul 2026)MOTS-cMitochondrial-derived peptide; human studies found only measured the body's own circulating levels (for example after repeated heat treatment), not administered MOTS-c.[14]GLP-1 & metabolic+437% searches
Quick verdict

Where the research points

Summary of studies, not a recommendation

Consider SS-31 if…

  • you want a product with an FDA label: Forzinity (elamipretide) is indicated, under accelerated approval, to improve muscle strength in Barth syndrome[23]
  • you want the randomized trial record (mitochondrial myopathy): the pivotal trial missed its primary endpoints: The pivotal randomized trial did not meet its primary endpoints (6-minute walk and fatigue score).[5]
  • you are tested in sport and want to avoid a WADA-prohibited substance: MOTS-c is prohibited by WADA at all times (check SS-31 (elamipretide)'s own status separately)[3]

Consider MOTS-c if…

  • you are weighing human evidence that, in our search, only measured the body's own MOTS-c (none gave it as a treatment): exercise raised plasma MOTS-c in non-Hispanic White survivors but not Hispanic survivors[16]
MOTS-c is not FDA approved. MOTS-c is prohibited in tested sport (WADA). Status labels come from public FDA and WADA records; see the sources below.
Side by side

Spec comparison

Showing 12 of 14 fields where the two differ. Half-life, Evidence strength are the same or both unknown.

FieldSS-31MOTS-c
ClassMitochondria-targeting peptideMitochondrial-derived peptide
Also calledelamipretide, Forzinitymots
CategoryLongevityGLP-1 & metabolic
FDA statusFDA accelerated approval for Barth syndrome (Sep 2025)PCAC voted 7–5 for 503A (Jul 2026)
PCAC vote, Jul 2026Not on the Jul 2026 agendaPCAC voted 7–5 for the 503A list (Jul 2026); not finalized
WADANot on the WADA Prohibited ListSS-31 (elamipretide) is not named on the list. It received FDA accelerated approval in 2025, so the S0 catch-all does not apply to it.Prohibited by WADA (S4.4.1)MOTS-c is named in S4.4.1 (metabolic modulators: AMPK activators), prohibited at all times.
Anti-doping detectionNone reportedanti-doping literature, as of 2 Oct 2026
  • A plasma (blood) test for MOTS-c has been validated to WADA standards.PMID 30394592
Human studies we summarised10 human (8 randomized or controlled) of 13 summarised7 human (4 randomized or controlled) of 15 summarised
Typical study doses
Vial sizes sold10 mg, 25 mg, 50 mg5 mg, 10 mg, 20 mg, 40 mg
US searches per month21,000 · +374% searches60,500 · +437% searches
Named in FDA warning letters, 2026Yes (24 Aug 2026)Not in the letters we track

Bracketed values are pending a sourced figure. Legal data reflects the regulatory events in our tracker.

Taken together?

SS-31 and MOTS-c together

People also search for this pair as a stack. The stack page covers timing and interaction questions as they are sourced. Evidence for the combination: No studies tested these together (PubMed search: 1 result, 2 Oct 2026).

Open the stack page
StackSS-31 + MOTS-c, taken as separate injectionsStack page

Sources

  1. 1FDA warning letters to five research-peptide sellersFDA warning letter (NuScience Peptides; 1 of 5) · 2026fda.govAccessed 2 Oct 2026
  2. 2FDA gives notice that 12 peptides will be removed from Category 2 (nominations withdrawn)FDA · 2026fda.govAccessed 2 Oct 2026
  3. 3World Anti-Doping Code International Standard Prohibited List 2026World Anti-Doping Agency · 2026wada-ama.orgAccessed 2 Oct 2026
  4. 4ReCLAIM-2: A Randomized Phase II Clinical Trial Evaluating Elamipretide in Age-related Macular Degeneration, Geographic Atrophy Growth, Visual Function, and Ellipsoid Zone Preservation.Ophthalmology science · 2025PMID 39605874Accessed 2 Oct 2026
  5. 5Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial.Neurology · 2023PMID 37268435Accessed 2 Oct 2026
  6. 6A 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.Genetics in medicine : official journal of the American College of Medical Genetics · 2021PMID 33077895Accessed 2 Oct 2026
  7. 7PubMed search: (elamipretide[tiab] OR Bendavia[tiab] OR "MTP-131"[tiab] OR Forzinity[tiab] OR (("SS-31"[tiab] OR SS31[tiab]) AND (peptide*[tiab] OR mitochondri*[tiab] OR cardiolipin[tiab] OR Szeto[tiab]))) (526 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  8. 8PubMed search: (elamipretide[tiab] OR Bendavia[tiab] OR "MTP-131"[tiab] OR Forzinity[tiab] OR (("SS-31"[tiab] OR SS31[tiab]) AND (peptide*[tiab] OR mitochondri*[tiab] OR cardiolipin[tiab] OR Szeto[tiab]))) AND (randomized[tiab] OR trial[tiab] OR patients[tiab]) (133 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  9. 9PubMed search: (elamipretide[tiab] OR Bendavia[tiab] OR "MTP-131"[tiab] OR Forzinity[tiab] OR (("SS-31"[tiab] OR SS31[tiab]) AND (peptide*[tiab] OR mitochondri*[tiab] OR cardiolipin[tiab] OR Szeto[tiab]))) AND (half-life[tiab] OR pharmacokinetic*[tiab]) (11 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  10. 10PubMed search: elamipretide[tiab] AND (TAZPOWER[tiab] OR "Barth syndrome"[tiab]) AND (randomized[tiab] OR crossover[tiab]) (6 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  11. 11PubMed search: elamipretide[tiab] AND (macular[tiab] OR "geographic atrophy"[tiab]) (9 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  12. 12PubMed search: elamipretide[tiab] AND (fibromyalgia[tiab] OR fatigue[tiab] OR "chronic pain"[tiab]) (19 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  13. 13Development of a mass spectrometry based detection method for the mitochondrion-derived peptide MOTS-c in plasma samples for doping control purposes.Rapid communications in mass spectrometry : RCM · 2019PMID 30394592Accessed 2 Oct 2026
  14. 14Repeated Heat Stress Modulates the Levels of the Mitokines MOTS-C and FGF21 in Active Men during Calf Muscle Immobilization.Medicine and science in sports and exercise · 2025PMID 40674654Accessed 2 Oct 2026
  15. 15Circulating levels of MOTS-c in patients with breast cancer treated with metformin.Aging · 2022PMID 36490309Accessed 2 Oct 2026
  16. 16Effect of aerobic and resistance exercise on the mitochondrial peptide MOTS-c in Hispanic and Non-Hispanic White breast cancer survivors.Scientific reports · 2021PMID 34413391Accessed 2 Oct 2026
  17. 17PubMed search: ("MOTS-c"[tiab] OR MOTSc[tiab]) (262 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  18. 18PubMed search: ("MOTS-c"[tiab] OR MOTSc[tiab]) AND (humans[mh] OR human[tiab] OR participants[tiab] OR patients[tiab] OR volunteers[tiab]) (179 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  19. 19PubMed search: ("MOTS-c"[tiab] OR MOTSc[tiab]) AND (randomized controlled trial[pt] OR "clinical trial"[pt] OR "meta-analysis"[pt] OR "systematic review"[pt]) (5 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  20. 20PubMed search: ("MOTS-c"[tiab] OR MOTSc[tiab]) AND (mice[tiab] OR mouse[tiab] OR rat[tiab] OR rats[tiab]) AND (injection[tiab] OR treatment[tiab] OR administration[tiab] OR treated[tiab]) (72 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  21. 21PubMed search: ("MOTS-c"[tiab] OR MOTSc[tiab]) AND (half-life[tiab] OR pharmacokinetic*[tiab]) (3 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  22. 22PubMed search: ("MOTS-c"[tiab] OR MOTSc[tiab]) AND (elamipretide[tiab] OR Bendavia[tiab] OR "MTP-131"[tiab] OR Forzinity[tiab] OR (("SS-31"[tiab] OR SS31[tiab]) AND (peptide*[tiab] OR mitochondri*[tiab] OR cardiolipin[tiab] OR Szeto[tiab])))PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  23. 23FORZINITY prescribing information (FDA label)FDA label, DailyMed · current labeldailymed.nlm.nih.govAccessed 2 Oct 2026
  24. 24Advisory committee backs 6 of 7 peptides for the 503A listNCPA · 2026ncpa.org

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