MOTS-c and mitochondrial peptides: where the evidence ends

MOTS-c has strong mouse biology and a human genetic signal. It has no clinical study of the native peptide. The only human interventional data come from an analog, CB4211, in a company-reported phase 1 trial. In July 2026 FDA wrote that the molecular targets through which MOTS-c acts remain unknown.

Key points

• MOTS-c is encoded in the mitochondrial 12S ribosomal RNA gene, and in mice it prevented insulin resistance and diet-induced obesity [1].
• In old mice, treatment started at 23.5 months was associated with greater physical capacity; in humans, exercise raises endogenous MOTS-c [5].
• An Asian variant of the gene (m.1382A>C) was associated with more type 2 diabetes in men in a meta-analysis of 27,527 people [8].
• The only human interventional data come from an analog, CB4211: 65 healthy adults in phase 1a and 20 adults with obesity for 4 weeks in phase 1b, with lower ALT and AST and no serious adverse events, according to the company [12].
• The FDA found no clinical studies of MOTS-c and noted that its molecular targets remain unestablished [13].

US status (October 2026): MOTS-c is not FDA-approved and has no lawful compounding pathway, and WADA prohibits it. MDside providers do not prescribe it. See the MOTS-c status page.

A gene inside a gene

For decades mitochondrial DNA was thought to encode only 13 respiratory-chain proteins, ribosomal RNAs and transfer RNAs. In 2001 a Japanese group identified humanin, a short peptide that, in cultured cells, protected against neuronal death induced by familial Alzheimer’s genes and β-amyloid [2]. Six small humanin-like peptides (SHLPs) were later described, encoded in the same 16S ribosomal RNA region. SHLP2 and SHLP3 reduced apoptosis in vitro, and circulating SHLP2 declined with age [3].

In 2015 a University of Southern California group described MOTS-c (mitochondrial open reading frame of the 12S rRNA-c): a 16-amino-acid peptide encoded within the 12S ribosomal RNA gene [1]. Together these compounds form the mitochondrial-derived peptide family: signals the mitochondrion sends to the rest of the cell and the body.

Mouse data are strong

In the original study the main target organ appeared to be skeletal muscle. In cells, MOTS-c inhibited the folate cycle and de novo purine synthesis, leading to AMPK activation. In mice, treatment prevented age-related and high-fat-diet insulin resistance as well as diet-induced obesity [1].

In 2021 the same group showed that MOTS-c improved physical performance in young (2 months), middle-aged (12 months) and old (22 months) mice. In a protocol started late in life, at 23.5 months, with intermittent dosing 3 times a week, treatment was associated with greater physical capacity and healthspan [5]. That is why it gets called an “exercise mimetic”. The term is an interpretation. It is not a clinical result.

• 16: amino acids in MOTS-c, encoded in the mitochondrial 12S rRNA [1]
• 27,527: people in the genetic meta-analysis of the m.1382A>C variant [8]
• 21% drop: ALT change with the analog CB4211, vs a 4% rise on placebo, over 4 weeks [12]

MOTS-c moves from the mitochondrion to the nucleus

A 2018 finding changed how the peptide is understood. Under metabolic stress, MOTS-c translocates to the nucleus in an AMPK-dependent manner and regulates a broad set of genes, including those with antioxidant response elements, and interacts with transcription factors such as NRF2 [4]. It is one of the first demonstrations that a mitochondrially encoded factor regulates the nuclear genome.

Which receptor or protein recognizes MOTS-c is still open. In 2024 a study proposed the kinase CK2 as a direct target: MOTS-c bound and activated CK2 in cell-free systems, and inhibiting CK2 blunted the prevention of muscle atrophy and the increase in glucose uptake in mice [6]. It is an important step, not yet independently replicated.

Human data are associations

Human data do not yet include administration of the native peptide. In the 2021 work, exercise induced endogenous MOTS-c expression in skeletal muscle and in the circulation [5]. In a Swedish study, 30 participants were randomized to endurance exercise, resistance exercise or control (10 per group). In the 45-minute cycling group, circulating humanin rose significantly, while MOTS-c showed only a trend to increase [10].

In a cross-sectional study of 225 people in Qatar, serum MOTS-c was lower in type 2 diabetes than in controls and correlated negatively with age, HbA1c and glucose [9]. These are associations. They do not show whether low peptide is a cause or a consequence of the metabolic disorder.

A Japanese variant links MOTS-c to longevity and diabetes

In 2015 a Japanese and Spanish group proposed that the m.1382A>C polymorphism, specific to Northeast Asian populations and located in the MOTS-c gene, might be among the mechanisms behind Japanese longevity. The authors stated that more work was needed [7].

In 2021 its functional effect was described: the variant causes an amino-acid change (K14Q) in the peptide. In a meta-analysis of three cohorts with 27,527 people, male carriers of the C allele had a higher prevalence of type 2 diabetes; female carriers did not. In one cohort the increase was limited to the least physically active men. In fat-fed mice, MOTS-c reduced weight and improved glucose tolerance, and the K14Q version did not [8]. The 2024 study added that K14Q binds CK2 less and that male carriers had a higher risk of sarcopenia and diabetes, depending on age and physical activity [6].

The only clinical trial tested an analog

Native MOTS-c has no published clinical trials. Its analog CB4211, developed by the company CohBar, reached a phase 1a/1b study. According to the company’s August 2021 release, phase 1a tested single and multiple doses over one week in 65 healthy adults. The phase 1b part was randomized, double-blind and placebo-controlled: 25 mg subcutaneously once daily for 4 weeks in 20 people with obesity and at least 10% liver fat (11 on CB4211, 9 on placebo) [12].

The trial met its primary tolerability endpoint with no serious adverse events. The only event in more than 10% of treated participants was mild to moderate injection-site reactions. ALT fell 21% vs a 4% rise on placebo, AST fell 28% vs 11%, and glucose fell 6% vs no change. Body weight showed only a trend. Liver fat fell substantially in both groups, including placebo [12]. We found no peer-reviewed publication of this trial in PubMed.

Where the evidence ends

• No clinical studies of the native peptide. In its July 2026 briefing document the FDA identified no clinical studies and no in-vivo pharmacokinetic data, and wrote that “the molecular targets through which MOTS-c acts remain unknown” [13].
• Stability in blood. In vitro, MOTS-c was rapidly hydrolyzed in human blood. The FDA noted it remains to be determined whether exogenous dosing reaches active concentrations over time [13].
• Questionable measurement. A mass-spectrometry method could not confirm the endogenous levels of 45.9 to 218.5 ng/mL reported by a commercial ELISA in 20 healthy people [11]. Read studies of circulating levels with that caution.
• Conflicts of interest. Several authors of the key studies declared being consultants and shareholders of CohBar, and the MOTS-c intellectual property was licensed to that company [5][6][8].
• Sport. MOTS-c is listed as a prohibited substance in the Global DRO database, based on the World Anti-Doping Agency list [13].

A vial sold online as MOTS-c carries none of the trial data above, which belong to a different molecule. A “research use only” label does not change that: see why that label is no shield.

The other side. MOTS-c biology is among the strongest of the longevity peptides: a described mechanism (AMPK, nuclear translocation and a candidate target, CK2) [1][4][6], an effect in old mice [5] and a human genetic variant that weakens the peptide and is associated with more diabetes [8]. The analog CB4211 was well tolerated in its first trial [12], and in 2026 the FDA advisory committee voted 7 to 5 in favor of adding MOTS-c to the compounding list [14]. For broader context, see anti-aging peptides, SS-31 and what the FDA actually said.

What this means for you

Keep MOTS-c off your menu. The committee vote is advice to FDA, and no rule has followed. If patients ask about metabolic or longevity peptides, the honest answer is that the human data belong to an analog in 20 people over 4 weeks. For what a metabolic program can lawfully include, see weight management.

References

1. Lee C, et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab. 2015;21(3):443-54. PMID 25738459. Link
2. Hashimoto Y, et al. A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer’s disease genes and Abeta. Proc Natl Acad Sci U S A. 2001;98(11):6336-41. PMID 11371646. Link
3. Cobb LJ, et al. Naturally occurring mitochondrial-derived peptides are age-dependent regulators of apoptosis, insulin sensitivity, and inflammatory markers. Aging (Albany NY). 2016;8(4):796-809. PMID 27070352. Link
4. Kim KH, et al. The mitochondrial-encoded peptide MOTS-c translocates to the nucleus to regulate nuclear gene expression in response to metabolic stress. Cell Metab. 2018;28(3):516-524.e7. PMID 29983246. Link
5. Reynolds JC, et al. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nat Commun. 2021;12(1):470. PMID 33473109. Link
6. Kumagai H, et al. MOTS-c modulates skeletal muscle function by directly binding and activating CK2. iScience. 2024;27(11):111212. PMID 39559755. Link
7. Fuku N, et al. The mitochondrial-derived peptide MOTS-c: a player in exceptional longevity? Aging Cell. 2015;14(6):921-3. PMID 26289118. Link
8. Zempo H, et al. A pro-diabetogenic mtDNA polymorphism in the mitochondrial-derived peptide, MOTS-c. Aging (Albany NY). 2021;13(2):1692-1717. PMID 33468709. Link
9. Ramanjaneya M, et al. Mitochondrial-derived peptides are down regulated in diabetes subjects. Front Endocrinol (Lausanne). 2019;10:331. PMID 31214116. Link
10. von Walden F, et al. Acute endurance exercise stimulates circulating levels of mitochondrial-derived peptides in humans. J Appl Physiol (1985). 2021;131(3):1035-1042. PMID 34351816. Link
11. Knoop A, et al. Development of a mass spectrometry based detection method for the mitochondrion-derived peptide MOTS-c in plasma samples for doping control purposes. Rapid Commun Mass Spectrom. 2019;33(4):371-380. PMID 30394592. Link
12. CohBar, Inc. CohBar announces positive topline results from the phase 1a/1b study of CB4211 under development for NASH and obesity. GlobeNewswire via BioSpace. 10 August 2021. Link
13. U.S. Food and Drug Administration. PCAC July 2026 briefing document: MOTS-c. Link
14. Pharmaceutical Executive. FDA votes to loosen restrictions on four peptides. 24 July 2026. Link

This is general information, not medical or legal advice. Rules vary by state and change. Confirm your own facts with counsel.