MOTS-c Peptide: What Mice Showed, What FDA Found, and the Human Trial That Hasn't Happened

MOTS-c stands for "mitochondrial open reading frame of the 12S rRNA type-c." Most of your genes sit in the cell nucleus. Mitochondria, the cell's energy plants, carry a small genome of their own. MOTS-c is a 16-amino-acid peptide coded by a short stretch of that mitochondrial DNA (FDA briefing, July 23, 2026).

Researchers group it with other "mitochondrial-derived peptides," such as humanin. It is sold online under the common name MOTS-c, which FDA notes is not an official drug name. FDA says it has seen different salts and derivatives sold under the same name.

Two findings drive the interest. First, in mice, MOTS-c acted like a metabolic signal: it worked through AMPK, an energy-sensing enzyme that exercise also switches on (Lee et al., 2015). Second, MOTS-c levels in people rise with exercise (Reynolds et al., 2021).

Put together, those findings led to the "exercise mimetic" label. The label describes a hypothesis. No human study has tested it.

MOTS-c itself: none published. FDA's July 2026 briefing says the nomination "did not include, and FDA has not identified, any publicly available clinical studies or human exposure data" for MOTS-c "via any route of administration." It also found no human pharmacokinetic data, meaning nobody has published how long MOTS-c lasts in a person's body.

Observational data. People's natural MOTS-c levels have been measured. Exercise raised MOTS-c in human muscle and blood (Reynolds et al., 2021). That tells us the body makes more of it during exercise. It does not tell us that adding more from a vial helps.

A related molecule: CB4211. CohBar, a biotech company, tested CB4211, a modified analog of MOTS-c, in a phase 1a/1b trial (NCT03998514). In the 4-week phase 1b part, 20 adults with obesity and fatty liver disease received daily injections of CB4211 or placebo. The company reported in August 2021:

• ALT, a liver-injury marker, fell 21% with CB4211 versus a 4% rise with placebo.
• AST fell 28% versus 11%.
• Glucose fell 6% versus no change.
• Liver fat fell by a similar amount in both groups.
• Injection-site reactions were the only side effect in more than 10% of people taking CB4211.

Sources are the CohBar press release, filed with the SEC, and an AASLD 2021 poster. We did not find these results in a peer-reviewed journal, and CB4211 is a different molecule from the MOTS-c sold online.

Most of the research so far comes from laboratory and animal studies. That does not tell us whether it works in people.

• Metabolism. In mice on a high-fat diet, MOTS-c prevented weight gain and insulin resistance. It also prevented age-related insulin resistance in mice (Lee et al., 2015).
• Physical performance. MOTS-c-treated mice ran better on performance tests across young, middle and old age groups (Reynolds et al., 2021).
• Stability. In a lab test cited by FDA, MOTS-c broke into shorter peptides within 15 to 60 minutes in human whole blood at 37°C. It is unclear whether an injection produces active levels over time.

FDA found no published nonclinical toxicity studies of MOTS-c. Safety in animals at the levels people use online has not been characterized in the literature.

In mouse muscle, MOTS-c interfered with the folate cycle, which raised levels of a molecule called AICAR. AICAR switches on AMPK, the same energy sensor activated by exercise and by the diabetes drug metformin (Lee et al., 2015). These mechanisms come from cells and mice.

Three things shape how to read this record.

1. MOTS-c research is young. The first major paper came out in 2015, and most work since has been in cells and rodents.
2. The one human program, CB4211, was a modified analog. CohBar reported results by press release and poster, and its long-term plan for the drug is unclear.
3. FDA's experts and its advisory committee disagreed. Details are below.

No verification reports have been reviewed for this profile. Straight Up Peptides has not purchased or commissioned testing of any MOTS-c sample. FDA found that publicly posted certificates of analysis for MOTS-c lacked impurity, endotoxin and contamination data. See how we verify claims.

MOTS-c is often sold alongside GLP-1 drugs for weight loss. Their records are far apart. Semaglutide is approved and has large human trials. MOTS-c has no published human trial. Retatrutide has finished phase 3 trials and is not yet approved, as covered in our retatrutide FDA approval article.

For the healing peptides that went through the same July 2026 FDA meeting, see BPC-157 and BPC-157 vs TB-500.

Methodology. Literature search on 2026-10-10: PubMed (MOTS-c, MOTSc, mitochondrial-derived peptide, CB4211), ClinicalTrials.gov (MOTS-c, CB4211), the FDA PCAC briefing slides for July 23, 2026, Health Canada advisories, and USADA. Company press releases are labelled as such. Forum posts were used to understand what readers ask, never as evidence of effect.

Primary sources.

• Lee C et al., 2015, Cell Metabolism: PMID 25738459
• Reynolds JC et al., 2021, Nature Communications: PMID 33473109
• FDA, MOTS-c evaluation slides, Pharmacy Compounding Advisory Committee, July 23, 2026: FDA briefing document
• CohBar press release, Aug 10, 2021 (SEC Exhibit 99.2): SEC; trial NCT03998514
• USADA, "What is the MOTS-c peptide?": USADA
• Health Canada advisory, April 9, 2026: Health Canada
• PCAC vote tallies: trade press reports (Fierce Pharma, FDA Law Blog), July 2026; final FDA minutes not located

Changes. Oct 10, 2026: first published. Oct 28, 2026: added the HHS draft enforcement-discretion policy, Federal Register document 2026-22192, after reading the public-inspection PDF and the linked policy PDF. The Bulks List entry is unchanged.

• HHS public inspection PDF: https://public-inspection.federalregister.gov/2026-22192.pdf
• HHS policy PDF: https://www.hhs.gov/sites/default/files/hhs-503a-peptide-enforcement-discretion-policy-appendix-b.pdf
• NBC News, October 28, 2026: https://www.nbcnews.com/health/health-news/rfk-jr-takes-shortcut-make-peptides-widely-available-rcna606133