MOTS-c
mitochondrial ORF of the 12S rRNA type-c, mitochondrial-derived peptide (MDP), mitochondrial microprotein
MOTS-c is a small peptide encoded not by the cell nucleus but by mitochondrial DNA, which makes it genuinely interesting biology. In mice it activates AMPK, improves insulin sensitivity and prevents diet-induced obesity. No completed human trial has ever administered it to people, so its effects in humans are unknown.
Mechanism
MOTS-c is a 16-amino-acid peptide encoded within the mitochondrial 12S ribosomal RNA gene, one of a small family of mitochondrial-derived peptides that also includes humanin. Its existence overturned the assumption that mitochondrial DNA encodes only respiratory chain components and RNAs, and established that mitochondria can send peptide signals to the rest of the cell and into the circulation. It is best understood as a mitokine: a signal by which mitochondria communicate their metabolic state.
Mechanistically, MOTS-c acts principally through the folate-methionine cycle. It inhibits the folate cycle, causing accumulation of the purine biosynthesis intermediate AICAR, which is an endogenous activator of AMP-activated protein kinase. AMPK activation then shifts cells toward catabolic metabolism: increased glucose uptake, increased fatty acid oxidation, suppressed lipogenesis and enhanced mitochondrial biogenesis. Under metabolic stress MOTS-c also translocates to the nucleus, where it associates with stress-responsive transcription factors and regulates antioxidant and metabolic gene expression, giving it a retrograde signalling role from mitochondrion to nucleus. Work published in 2024 reported direct binding to and activation of casein kinase 2 in skeletal muscle, offering an additional and more proximal target. Its expression rises with exercise in both mice and humans, and circulating levels decline with age, which underpins the interest in it as a candidate exercise mimetic.
What the research shows
The preclinical literature is substantial, growing rapidly, and largely consistent. The founding study showed that MOTS-c administration in mice increased insulin sensitivity, prevented diet-induced obesity and reversed age-dependent insulin resistance. Subsequent rodent work has reported protection against muscle atrophy, improved physical capacity in aged mice, and anti-inflammatory actions across several tissues. A 2021 study characterised MOTS-c as exercise-induced and reported that treating aged mice improved physical capacity. This is a genuinely active research field, and the underlying biology is not in doubt.
The human evidence is a different matter and needs stating without hedging. Human research on MOTS-c consists almost entirely of observational work: measuring endogenous circulating MOTS-c concentrations and correlating them with conditions such as polycystic ovary syndrome, cardiovascular disease or dialysis outcomes, and genetic association studies of the mitochondrial m.1382A>C polymorphism, which alters MOTS-c at position 14 and has been linked to exceptional longevity in Japanese cohorts and to diabetes risk in Northeast Asian populations. None of this establishes that administering MOTS-c to a person does anything.
As of August 2026, no completed interventional human trial of MOTS-c administration has been published. One phase 2 trial, NCT07505745, evaluating MOTS-c for insulin sensitivity in 120 adults with prediabetes and overweight or obesity, is registered and recruiting; this audit verified the registry record directly and confirmed that no results have been posted. Everything currently claimed about MOTS-c in humans, whether relating to fat loss, exercise capacity, longevity or metabolic health, is extrapolation from mice and from correlational data. The observation that low MOTS-c levels accompany disease does not establish that raising them treats it, and this inference error is the single most common misuse of the MOTS-c literature. It is worth noting that when the FDA reviewed the evidence for MOTS-c in 2026 in the compounding context, its own assessment was that the effectiveness and safety data were insufficient.
Evidence assessment
Preclinical only
All evidence for administered MOTS-c comes from cell and animal work; human research is observational or genetic, and the only registered interventional human trial was verified as still recruiting with no results reported. Every citation was checked against PubMed or ClinicalTrials.gov.
Tiers are applied consistently across the library and re-checked when new trials read out. Read the grading method.
Key studies
The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance Preclinical only
MOTS-c targeted the folate cycle to drive AICAR accumulation and AMPK activation, and its administration prevented diet-induced obesity and reversed age-dependent insulin resistance in mice.
MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis Preclinical only
MOTS-c expression increased with exercise, and administration to aged mice improved physical capacity and muscle homeostasis.
The mitochondrial-derived peptide MOTS-c: a player in exceptional longevity? Limited evidence
The m.1382A>C polymorphism, which alters MOTS-c at position 14, was associated with exceptional longevity in Japanese men.
A pro-diabetogenic mtDNA polymorphism in the mitochondrial-derived peptide, MOTS-c Limited evidence
The m.1382A>C MOTS-c variant was associated with increased type 2 diabetes risk in Northeast Asian populations, with the variant peptide showing reduced metabolic activity.
MOTS-c modulates skeletal muscle function by directly binding and activating CK2 Preclinical only
MOTS-c directly bound and activated casein kinase 2, identifying a more proximal molecular target than the folate cycle mechanism.
MOTS-c for Improving Insulin Sensitivity in Adults With Prediabetes and Overweight/Obesity Limited evidence
No results reported. The trial is listed as recruiting and is the first registered interventional study to administer MOTS-c to human participants.
Safety
There are no human safety data for administered MOTS-c, because no completed interventional human trial has been published. Rodent studies have not reported prominent toxicity at the doses used, but rodent tolerability across short experiments is a weak basis for inference about human safety, and it says nothing about chronic exposure. One specific consideration deserves mention: MOTS-c is a systemic AMPK activator, and AMPK sits at the centre of cellular energy regulation; chronic pharmacological manipulation of that node has consequences that short animal studies are not designed to detect. A peptide that pushes cells toward catabolic metabolism should not be assumed to be uniformly beneficial across all cell types and tissues. The relationship between MOTS-c and cancer biology is unresolved in both directions. The FDA's 2026 briefing assessment for the compounding advisory committee concluded that the available safety evidence was insufficient to support inclusion on the 503A Bulks List. Separately, the practical risk with consumer products is the usual one: unregulated synthesis with unverified identity, purity and sterility. A peptide sold as MOTS-c has not been shown to contain MOTS-c.
Regulatory status
| Jurisdiction | Status |
|---|---|
| United Kingdom | Not licensed by the MHRA for any indication. Not an authorised medicine and not an authorised novel food. Supply for human use would fall outside the Human Medicines Regulations 2012. It is available in the UK only through unregulated online channels. |
| United States | Not approved for any indication. MOTS-c was nominated for the FDA's section 503A bulk drug substances list and placed in Category 2 (substances that may present significant safety risks). It was subsequently removed from Category 2 as a procedural step so that FDA could evaluate it for possible inclusion on the 503A Bulks List; removal from Category 2 is not authorisation to compound. At the Pharmacy Compounding Advisory Committee meeting of 23 July 2026, FDA's own briefing document proposed that MOTS-c (free base) and MOTS-c acetate NOT be added to the Bulks List, on the grounds of insufficient effectiveness and safety evidence for the nominated injectable metabolic uses. The committee nonetheless voted to recommend inclusion. PCAC recommendations are advisory and not binding on FDA, and no final decision has been made. MOTS-c has no lawful status as a dietary supplement, and material sold to consumers is an unapproved drug. |
| WADA (sport) | Not specifically named on the WADA Prohibited List. As a non-approved pharmacological substance it falls within class S0 (Non-Approved Substances) and is therefore prohibited at all times for athletes under the Code. Given its characterisation as an exercise-responsive metabolic regulator, explicit listing in future is plausible. |
Questions
Not as an administered treatment in any completed study. Human MOTS-c research to date is observational, measuring naturally occurring blood levels and correlating them with disease, or genetic, examining the m.1382A>C variant. One phase 2a trial in prediabetes, NCT07505745, is registered and recruiting as of 2026 but has reported nothing. Every claim about what injecting MOTS-c does to a person is currently extrapolation from mice.
That does not follow, and the inference is the most common error in how this literature is used. Studies finding reduced circulating MOTS-c in polycystic ovary syndrome, kidney disease or cardiovascular disease are cross-sectional correlations. Low levels may be a consequence of mitochondrial dysfunction rather than a cause of the disease, or both may follow from something else. Only an intervention trial can distinguish these, and none has reported.
It is a plausible candidate, not an established one. MOTS-c rises with exercise in both mice and humans, and administering it improved physical capacity in aged mice. That is a real and interesting finding. But no human has been shown to gain fitness or metabolic benefit from receiving MOTS-c, and 'exercise mimetic' is a hypothesis the field is testing rather than a description of demonstrated effect.
It is not approved as a medicine anywhere. In the US it was placed in Category 2 of the FDA's interim 503A bulk drug substances list, then removed from that category as a procedural step so FDA could assess it for the 503A Bulks List. At the Pharmacy Compounding Advisory Committee meeting on 23 July 2026, FDA proposed against adding it, citing insufficient effectiveness and safety evidence; the committee voted to recommend inclusion anyway. That vote is advisory only and FDA has not made a final decision, so nothing about this authorises compounding today. In the UK it is neither a licensed medicine nor an authorised novel food. Athletes should note it would fall under WADA class S0 as a non-approved substance.