Which is better, MOTS-c or SS-31 (elamipretide)?
SS-31 wins on evidence grade (human RCT versus animal only) and regulatory status (an FDA approved drug versus a substance still awaiting a final FDA decision on the 503A bulks list). Its approval is narrow, limited to Barth syndrome and based on a small crossover trial that missed its primary endpoints plus a 168 week open label extension, and MMPOWER-3 found no benefit over placebo in primary mitochondrial myopathy. MOTS-c has no human treatment trial at all. [1] [5] [6] [7] [8] [10]
How do MOTS-c and SS-31 (elamipretide) compare?
| Dimension | MOTS-c | SS-31 (elamipretide)Favored |
|---|---|---|
| Evidence grade [1] [2] [3] [5] [6] | Animal only. Mouse metabolic and exercise studies; human data are exercise induced blood levels and a genetic association with type 2 diabetes. | Human RCT. TAZPOWER (12 patients with Barth syndrome) and MMPOWER-3 (218 adults with primary mitochondrial myopathy), plus earlier phase 2 trials. |
| Mechanism [1] [4] | A 16 amino acid peptide encoded by mitochondrial DNA that signals outward: it activates AMPK via the folate cycle and AICAR, raising muscle glucose uptake and fat oxidation. | A synthetic tetrapeptide that works inside mitochondria: it binds cardiolipin on the inner membrane, stabilizing cristae and respiratory chain supercomplexes and improving ATP production. |
| Key trial results [1] [2] [5] [6] [7] | No human treatment trial. In mice, prevented diet induced obesity and insulin resistance and improved running capacity at all ages. | TAZPOWER missed its 12 week crossover endpoints but the open label extension showed sustained gains in 6 minute walk distance and strength at 168 weeks; MMPOWER-3 showed no significant difference from placebo at 24 weeks. |
| Human safety data [1] [6] [7] | None published. Theoretical added glucose lowering with diabetes drugs based on mouse data. | Generally well tolerated in trials; injection site reactions were the most common adverse event, with headache, dizziness, and eosinophilia in some participants. |
| FDA and compounding status [8] [9] [10] | Not FDA approved. Removed from the 503A Category 2 list on April 15, 2026; PCAC recommended it for the 503A bulks list in July 2026; no final rule at verification. | FDA approved (accelerated approval, Forzinity, September 2025) for Barth syndrome. Because an approved product exists, it is not eligible for routine 503A compounding. |
| WADA status [11] | Prohibited at all times under S4.4 (metabolic modulators), where it is named as an activator of AMP-activated protein kinase. | Not prohibited. |
| Note: Because elamipretide is now an approved drug, it no longer falls under S0. | ||
| Human dosing reference [1] [2] [6] [8] | Not established. Mice received 0.5 mg/kg daily (metabolic studies) up to 15 mg/kg (exercise studies). | Trials used 40 mg subcutaneously once daily; the Forzinity label gives weight based dosing for Barth syndrome. |
| Access path [8] [10] | No lawful compounded channel today: PCAC recommended it for the 503A bulks list in July 2026, but the recommendation is advisory and FDA has not published a final rule. | Specialist prescription for Barth syndrome through specialty pharmacy; other uses only in clinical trials. Research listings labeled SS-31 are not the approved drug. |
Evidence grade and regulatory status
Pulled from each peptide’s own record, so it stays in step with the peptide pages.
| Attribute | MOTS-c | SS-31 (elamipretide) |
|---|---|---|
| Class | Mitochondrial derived peptide (16 amino acids) encoded in the 12S rRNA region of mitochondrial DNA | Synthetic mitochondria targeted tetrapeptide (D-Arg-Dmt-Lys-Phe-NH2) that binds cardiolipin on the inner mitochondrial membrane |
| What it is | A 16 amino acid peptide coded by mitochondrial DNA that improves metabolism and exercise capacity in mice; human data limited to blood levels and genetics. | Mitochondria targeted peptide FDA approved in 2025 as Forzinity for rare Barth syndrome, after a large mitochondrial muscle disease RCT missed its main goal. |
| Evidence | Evidence: Animal-only evidence | Evidence: Human RCT evidence |
| FDA status | Regulatory: Under FDA review | Regulatory: FDA approved |
| Compounding | MOTS-c was placed on the FDA 503A Category 2 list (substances with significant safety risks) in 2023 and removed from it on April 15, 2026. On July 23 to 24, 2026 the Pharmacy Compounding Advisory Committee recommended adding MOTS-c to the 503A bulks list. As of the last verification date FDA has not published a final rule, so compounding pharmacies and state boards vary in whether they will fill it. It is not an FDA approved drug and is not eligible for 503B outsourcing. | FDA granted accelerated approval to elamipretide (Forzinity) in September 2025 for Barth syndrome, making it the first approved treatment for that disease. Because an FDA approved product exists, elamipretide is not eligible for routine 503A compounding, and it has not been listed on the 503A bulks list. Material sold online as SS-31 for research use is not the approved drug and is not lawful for human use. |
| WADA | WADA: WADA prohibited | WADA: Not WADA prohibited |
| Routes | Subcutaneous injection (as sold), Intraperitoneal injection (animal studies) | Subcutaneous injection once daily (Forzinity label and trials), Intravenous infusion (earlier cardiac and kidney trials) |
| Typical cost | No lawful compounded price: MOTS-c is not on the 503A bulks list, and PCAC's July 2026 recommendation is advisory until FDA publishes a final rule. Advertised clinic prices are not a comparable price. Products sold as research chemicals are not lawful for human use and are not verified for identity or purity. | Forzinity pricing for Barth syndrome is set for a rare disease and is largely covered through specialty pharmacy and manufacturer patient programs; a cash price is not publicly listed. Research chemical listings for SS-31 exist but those products are not lawful for human use. |
| Last verified |
Has MOTS-c been tested directly against SS-31 (elamipretide)?
No published trial has compared MOTS-c and SS-31 (elamipretide) directly. The dimensions above come from separate studies and labels, and cross-trial comparisons are less reliable than a direct trial.
What do MOTS-c and SS-31 (elamipretide) cost?
| Dimension | MOTS-c | SS-31 (elamipretide) |
|---|---|---|
| Typical cost | No lawful compounded price: MOTS-c is not on the 503A bulks list, and PCAC's July 2026 recommendation is advisory until FDA publishes a final rule. Advertised clinic prices are not a comparable price. Products sold as research chemicals are not lawful for human use and are not verified for identity or purity. | $66,000 per month |
| Price detail | MOTS-c price by channel | SS-31 (elamipretide) price by channel |
Where a price index exists, the range is the cash price per month across branded, compounded, and telehealth channels, without insurance. The cost pages give each channel separately with its sources. Otherwise the typical cost from the peptide record is shown. Legal access depends on your state: see peptide legality by state.
Frequently asked questions
Which is better for mitochondrial health or energy?
Neither has been shown to improve energy or mitochondrial health in healthy people. SS-31 is approved only for Barth syndrome and did not beat placebo in adults with primary mitochondrial myopathy in MMPOWER-3. MOTS-c has only mouse data. [2] [6] [8]
Is SS-31 FDA approved?
Yes. Elamipretide received accelerated approval as Forzinity in September 2025 for Barth syndrome, supported by the TAZPOWER trial and its 168 week open label extension. Products sold online as SS-31 for research are not the approved drug and are not lawful for human use. [5] [7] [8]
Can I get MOTS-c from a compounding pharmacy?
Not from bulk today. FDA removed MOTS-c from the Category 2 list in April 2026 and PCAC recommended it for the 503A bulks list in July 2026, but the recommendation is advisory: until FDA publishes a final rule it is not on the bulks list, so a 503A pharmacy has no federal basis to compound it from bulk, and state boards cannot authorize what federal law does not. [9] [10]
Do they work the same way?
No. SS-31 acts inside the mitochondrion by binding cardiolipin and stabilizing the respiratory chain. MOTS-c is a signaling peptide made from mitochondrial DNA that acts on the cell's metabolism through AMPK. [1] [4]
Are they allowed for tested athletes?
MOTS-c is prohibited at all times under WADA section S4.4 (metabolic modulators). SS-31 is not prohibited now that it is an approved drug, though athletes should confirm against the current list. [11]
Conditions studied
From the blog
- MOTS-c for weight loss: what mouse and human studies show
MOTS-c prevented diet-induced obesity in mice, but no human trial has tested it for weight loss. What the mouse data show, what human blood studies found, and where it stands legally.
Sources
Numbered citations above point to these primary sources. PubMed entries link to the indexed abstract.
- [1]Lee C et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab 2015PubMed 25738459, 2015
- [2]Reynolds JC et al. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nat Commun 2021PubMed 33473109, 2021
- [3]Zempo H et al. A pro-diabetogenic mtDNA polymorphism in the mitochondrial-derived peptide, MOTS-c. Aging (Albany NY) 2021PubMed 33468709, 2021
- [4]Birk AV et al. The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin. J Am Soc Nephrol 2013PubMed 23813215, 2013
- [5]Reid Thompson W et al. A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome. Genet Med 2021 (TAZPOWER)PubMed 33077895, 2021
- [6]Karaa A et al. Efficacy and safety of elamipretide in individuals with primary mitochondrial myopathy: the MMPOWER-3 randomized clinical trial. Neurology 2023PubMed 37268435, 2023
- [7]Thompson WR et al. Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER. Genet Med 2024PubMed 38602181, 2024
- [8]FDA prescribing information for Forzinity (elamipretide) injection, via DailyMedFDA
- [9]FDA: Bulk drug substances used in compounding under section 503A of the FD&C Act (links to the Category 1, 2, and 3 lists and the bulks list)FDA
- [10]FDA Pharmacy Compounding Advisory Committee meetings (July 2026 meeting on peptide nominations)FDA
- [11]WADA Prohibited ListWADA
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PeptideAgent. (2026, September 27). MOTS-c vs SS-31 (elamipretide): evidence, cost, and legality. https://peptideagent.ai/compare/mots-c-vs-ss-31- HTML link
<a href="https://peptideagent.ai/compare/mots-c-vs-ss-31">MOTS-c vs SS-31 (elamipretide): evidence, cost, and legality</a>, PeptideAgent, updated September 27, 2026.