MOTS-c: what the research literature shows

What it is

A peptide written inside a ribosomal RNA gene

Mitochondria carry a genome of their own.² In 2015 Lee and colleagues reported a short open reading frame, a stretch of DNA that can be read as a small protein, inside the mitochondrial gene for 12S ribosomal RNA.¹ It encodes a peptide of 16 amino acids that they named MOTS-c, for mitochondrial open reading frame of the 12S rRNA-c.¹

Review A 2020 review counts eight such mitochondrial-derived peptides: MOTS-c from the 12S rRNA gene, and humanin plus six small humanin-like peptides from the 16S rRNA gene.¹³ It notes that these short reading frames do not necessarily carry the usual hallmarks of protein-coding genes.¹³ The article on mitochondrial peptide research compares this family with peptides designed to reach mitochondria.

Sequence and chemistry

PubChem gives the sequence as Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg, with the formula C101H152N28O22S2, a molecular weight of 2174.6 g/mol and both ends of the chain unmodified.¹⁴ The chain holds two methionine residues and one tryptophan.¹⁴ An assay built for doping control tracks two oxidation products of the peptide beside the intact molecule.¹⁰

Human study A natural variant exists: a single-letter change in mitochondrial DNA, described as specific to Asian populations, replaces the lysine at position 14 with glutamine, and the resulting peptide is written K14Q.¹⁵

How it is studied

Most of the MOTS-c work cited here sits on the lower rungs described in the guide to evidence levels in peptide research. Cell experiments apply metabolic stress, such as glucose restriction, and follow where the peptide goes and which genes respond.² Mouse studies use high-fat feeding, aging, removal of the ovaries and running tests.¹¹⁶¹⁷

Human studies differ: they measure the peptide the body makes, in plasma or in skeletal muscle.⁷¹⁸ Some use an immunoassay called ELISA, and one laboratory built a method based on liquid chromatography and mass spectrometry, a technique covered in the guide to analytical methods for peptides.¹⁰¹⁹

What the literature reports

The proposed mechanism

Cell study In the original report, the cellular actions of MOTS-c inhibited the folate cycle and the de novo synthesis of purines tied to it, which led to activation of AMPK, a kinase that senses the energy state of the cell.¹²⁰ The authors named skeletal muscle as the apparent primary target organ.¹

Cell study A 2018 paper described a second route: after metabolic stress, MOTS-c moved into the cell nucleus in an AMPK-dependent manner.² There it regulated a broad range of genes in response to glucose restriction and interacted with the stress-responsive transcription factor NRF2.²

Cell study A 2024 study proposed a direct protein target: MOTS-c bound the kinase CK2 and activated it in cell-free systems, while the K14Q variant bound it less well and did not activate it.⁶

The papers cited here do not reduce these three accounts to a single mechanism.¹²⁶

Metabolic studies in mice

Animal study Lee and colleagues reported that MOTS-c treatment in mice prevented the insulin resistance that develops with age and with high-fat feeding, and prevented diet-induced obesity.¹

Animal study In mice whose ovaries had been removed, a separate group found that MOTS-c treatment prevented obesity and insulin resistance, increased brown fat activation and reduced fat accumulation in white fat.¹⁶ An AMPK blocker weakened its effect on lipid metabolism in fat cells.¹⁶

Animal study High-fat-fed male mice given MOTS-c showed lower weight and better glucose tolerance, mice given the K14Q variant did not, and female mice were unaffected.¹⁵

Animal study The CK2 study added that MOTS-c given to mice prevented skeletal muscle atrophy and raised muscle glucose uptake, and that suppressing CK2 activity blunted both effects.⁶ The peptide stimulated CK2 in muscle and suppressed it in fat.⁶

Exercise and aging studies in mice

Animal study Reynolds and colleagues reported that MOTS-c enhanced physical performance in young, middle-aged and old mice, and that intermittent treatment begun late in life increased physical capacity and healthspan.³

Animal study A single-author study found that four to eight weeks of voluntary running raised MOTS-c protein in rodent hindlimb muscles.¹⁷ Untrained mice given the peptide once ran longer and farther in an acute exercise test.¹⁷ After a bout of downhill running, MOTS-c had moved into the nucleus in two of six soleus muscles and in none of the plantaris muscles from the same animals.¹⁷

Animal study A 2026 study from a Copenhagen group, using two transgenic mouse strains, found that MOTS-c raised the bioenergetic performance of muscle mitochondria without an apparent change in respiratory protein content, and that the effect depended on both AMPK and the coactivator PGC-1α.²⁰

The body’s own MOTS-c in people

Human study Studies of circulating MOTS-c and body weight point in different directions. A study of ten lean and ten obese people found similar plasma concentrations in the two groups.⁷ A case-control study of 97 children and adolescents found lower levels in the obese group, a difference seen in boys and not in girls.⁸ A study of 22 lean and 32 obese adults found higher levels in the obese group, and no change six months after bariatric surgery in the ten patients followed.⁹

Human study In a cross-sectional study of 225 people, serum MOTS-c was lower in those with type 2 diabetes than in controls, and lower at older ages.²¹ In healthy men, circulating MOTS-c was lower at older ages, yet its expression in skeletal muscle was about 1.5 times higher in middle-aged and older men than in young men.¹⁸

Human study The measurements themselves are uncertain. Typical concentrations in three of these studies were about half a nanogram per millilitre, several hundred nanograms per millilitre and a few hundred picograms per millilitre.⁷⁸⁹ A doping-control laboratory validated a mass spectrometry assay able to detect the peptide in plasma at 100 picograms per millilitre, and with it could not confirm the levels that a commercial ELISA reported in 20 healthy subjects.¹⁰

Exercise and circulating levels

Human study Reynolds and colleagues reported that exercise induced endogenous MOTS-c expression in human skeletal muscle and in the circulation.³ In a randomized study of 30 subjects, one bout of endurance exercise raised circulating humanin significantly, while MOTS-c showed only a trend toward an increase and resistance exercise raised neither.²²

Human study In a secondary analysis of a 16-week exercise trial in breast cancer survivors, MOTS-c rose in non-Hispanic White participants and not in Hispanic participants.¹⁹ In the Copenhagen study, MOTS-c rose in the fluid around muscle fibres during one-legged exercise, but the difference between blood entering and leaving the leg did not change, and the authors suggest that muscle may not be the source of circulating MOTS-c during exercise.²⁰

Carriers of the K14Q variant

Human study A meta-analysis of three cohorts totalling 27,527 people found a higher prevalence of type 2 diabetes in men who carry the variant, and not in women.¹⁵ A later paper reported a higher risk of sarcopenia and type 2 diabetes in male carriers, depending on age and physical activity, and a lower risk of type 2 diabetes in female carriers at certain ages.⁶ These are associations in population data, not experiments.

Human evidence

We found no published study in which MOTS-c was given to people. A PubMed search on 8 October 2026, limited to clinical trial publication types, returned five records, and each measured the body’s own peptide.⁴ The FDA states that it has not identified any human exposure data on drug products containing MOTS-c.²³

Two registrations bear on the question:

• Human study MOTS-c itself. ClinicalTrials.gov lists a phase 2a, randomized, double-blind, placebo-controlled trial in adults with prediabetes and overweight or obesity, sponsored by Hudson Biotech, with a planned enrolment of 120.⁵ Of nine registered studies that mention MOTS-c it was the only one that gives the peptide, and it was recruiting, with no results posted, on 8 October 2026.⁵²⁴
• Human study An analogue, CB4211. The registry lists a phase 1a/1b study by CohBar, completed in April 2021 with 88 participants and no posted results.²⁵ A company press release of August 2021 describes CB4211 as an analogue of MOTS-c and reports no serious adverse events, with larger falls in two liver enzymes and in glucose than with placebo over four weeks in 20 obese subjects with fatty liver disease, while liver fat fell by a similar amount in both groups.²⁶ That is a sponsor’s summary of a different molecule, not a peer-reviewed result, and a PubMed search for CB4211 returned no records.²⁷

Review A 2026 review of peptides marketed directly to patients, MOTS-c among them, concluded that many unapproved peptides show favourable results in animal models while rigorous human safety data are scarce.²⁸

Regulatory status

Each statement below was checked against the authority’s own page on 8 October 2026.

• Canada. A search of Health Canada’s Drug Product Database for MOTS-c as an active ingredient returned no product.¹¹ In a public advisory last updated on 9 April 2026, Health Canada named MOTS-c among examples of unauthorized injectable peptide drugs it had seized, and said that a research-use-only label does not exempt a product from regulatory requirements.²⁹
• United States. A search of the FDA’s approved-drug data for MOTS-c as an active ingredient returned no match.¹² The FDA lists MOTS-c among bulk drug substances that were in category 2 of its interim compounding policies, the category for substances that may present significant safety risks, and whose nominations were later withdrawn.²³ Its entry cites a possible risk of immunogenicity and a lack of information on whether the substance would cause harm in humans.²³
• Sport. The World Anti-Doping Agency’s 2026 Prohibited List names MOTS-c as an example of an AMPK activator in section S4.4.1 of class S4, hormone and metabolic modulators, which are prohibited at all times.³⁰

Horizon Peptides supplies MOTS-c for laboratory research use only.

In the laboratory

Horizon lists MOTS-c as a lyophilized powder in sealed vials and as a pre-mixed solution in a pen; see the MOTS-c vial. Two points from the sources above bear on bench work:

• Chemistry study The doping-control method tracks four metabolites formed in vitro and two oxidation products as well as the intact peptide, which suggests a sample may hold more than one species.¹⁰
• Human study Quantification depends on the method: in one laboratory’s comparison, immunoassay and mass spectrometry gave considerably different readings, so a concentration means little without the assay that produced it.¹⁰

The guide to peptide stability and degradation explains oxidation and the other breakdown routes. General conditions for keeping lyophilized material are in the peptide storage guide. Batch documents, when they exist, are published on the Lab Results page.