MOTS-c: The Mitochondrial Peptide Linked to Metabolism, Insulin Sensitivity and Cellular Stress

MOTS-c (Mitochondrial Open Reading Frame of the 12S rRNA type-c) is a small peptide that differs from most well-known peptides in one fundamental way: it is encoded by mitochondrial DNA rather than the nuclear genome. Just 16 amino acids long, MOTS-c is studied as part of a new class of molecules — the mitochondrial-derived peptides (MDPs). Scientific interest centres on its role in energy metabolism, insulin sensitivity, the response to metabolic stress and adaptation to exercise. Important: much of the evidence comes from preclinical models — human data is limited and does not support the conclusion that MOTS-c is a proven treatment for metabolic or age-related disease.

What is MOTS-c?

MOTS-c is a 16-amino-acid peptide encoded in a small open reading frame within the mitochondrial 12S rRNA gene. Mitochondria are traditionally viewed as the cell's power plants, but modern research shows they participate actively in cellular signalling. MOTS-c is one of the peptides through which mitochondria may relay information to other parts of the cell, including the nucleus: under certain conditions of metabolic stress, MOTS-c can move into the nucleus and influence the expression of genes tied to the adaptive cellular response.

MOTS-c and energy metabolism

One of its most-studied features is a potential role in regulating how cells use nutrients — with particular attention to skeletal muscle, one of the body's main glucose consumers. In experimental models, MOTS-c activates metabolic machinery tied to AMPK (AMP-activated protein kinase), a key regulator of cellular energy balance. One proposed mechanism runs through the folate cycle and de novo purine synthesis, accumulating metabolites capable of activating AMPK: MOTS-c → folate metabolism → AICAR-related signalling → AMPK → adaptation of energy metabolism.

MOTS-c and insulin sensitivity

In a study published in Cell Metabolism in 2015, MOTS-c administration in mice prevented age- and diet-induced insulin resistance, with effects on body weight and metabolic homeostasis. Later experiments also showed improved insulin sensitivity and altered lipid metabolism in animal models — a 2019 study found MOTS-c influencing several metabolic pathways and increasing β-oxidation in diet-induced obese mice. Interesting results, to be kept distinct from clinically proven effects in humans.

What do the human studies show?

In humans the picture is far more limited — studies mostly measure natural circulating MOTS-c and its relationship to metabolic characteristics. In a small study of 20 participants (10 lean, 10 with obesity), plasma MOTS-c did not differ significantly between groups; correlations with insulin sensitivity measures appeared, but more clearly in the lean participants. This illustrates why animal results cannot be transferred automatically to people.

MOTS-c and exercise

Exercise triggers a range of metabolic and mitochondrial adaptations, and MOTS-c is among the mitochondrial-derived peptides studied as a potential part of that adaptive response. Human studies have observed changes in circulating MOTS-c after exercise, including endurance and resistance training.

MOTS-c and AMPK

AMPK acts as the cell's energy-status sensor: under energy deficit it activates mechanisms that support energy production and curb energy-hungry processes. Experimental data links MOTS-c to AMPK signalling, with implications for glucose metabolism, fatty acid oxidation, energy balance, metabolic adaptation to exercise and the cellular stress response.

MOTS-c and mitochondrial stress

Under metabolic or oxidative stress the peptide may take part in retrograde signalling — communication from mitochondria to the nucleus. In such conditions MOTS-c can translocate to the nucleus and influence expression of stress-adaptation genes — suggesting a role broader than simple energy regulation.

MOTS-c and ageing

Several publications report that MOTS-c levels may decline with age, prompting the hypothesis that the peptide helps maintain metabolic homeostasis during ageing. Experimental models show potential effects on insulin sensitivity, metabolic adaptation, muscle function, adipose tissue and cellular stress. These observations do not yet demonstrate that administering MOTS-c to humans slows ageing or extends lifespan.

Newer research

Recent experimental work examines MOTS-c in the cellular ageing of pancreatic islet cells. A 2025 study found reduced MOTS-c with ageing and cellular senescence, while administration in animal models influenced β-cell senescence and glucose intolerance; the authors also report lower circulating MOTS-c in people with type 2 diabetes. Interesting directions — still primarily a preclinical evidence base, not an established therapeutic use.

What we still do not know

• Pharmacokinetics — how exogenous MOTS-c distributes and is metabolised in humans;
• Biological stability — as a small peptide it may degrade quickly, a common hurdle in peptide development;
• Long-term safety — no long-term controlled clinical data;
• Clinical efficacy — whether model results can be reproduced in well-controlled trials;
• Exact mechanism — the full biology of MOTS-c and its interactions with other signalling systems remain unresolved.

MOTS-c in brief

• Origin — mitochondrial DNA;
• Length — 16 amino acids;
• Main interest — metabolic regulation and cellular stress;
• AMPK signalling — supported by preclinical data;
• Insulin sensitivity — positive results mainly in animal models;
• Exercise link — observed in experimental and human studies;
• Ageing — an active research area;
• Clinical evidence — still limited;
• Approved therapy — none.

Conclusion

MOTS-c is one of the most interesting members of the new class of mitochondrial-derived peptides — with the unusual distinction of being encoded directly in the mitochondrial genome. Research links it to AMPK signalling, glucose and lipid metabolism, cellular stress adaptation and the physiology of exercise. The preclinical results are promising, including for insulin sensitivity and metabolic homeostasis; in humans the evidence remains far more limited. MOTS-c is most accurately viewed as a subject of active scientific research — not a proven therapy for weight loss, diabetes, ageing or any other condition.

1. 1.Lee C, Zeng J, Drew BG, et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab. 2015;21(3):443–454.
2. 2.Kim KH, Son JM, Benayoun BA, Lee C. MOTS-c: A Mitochondrial-Encoded Regulator of the Nucleus. Bioessays. 2019.
3. 3.The mitochondrial-derived peptide MOTS-c is a regulator of plasma metabolites and enhances insulin sensitivity. Physiol Rep. 2019.
4. 4.Plasma MOTS-c levels are associated with insulin sensitivity in lean but not in obese individuals. J Investig Med. 2018.
5. 5.Exercise, Mitohormesis, and Mitochondrial ORF of the 12S rRNA Type-C (MOTS-c). Diabetes Metab J. 2022.
6. 6.Acute endurance exercise stimulates circulating levels of mitochondrial-derived peptides in humans. J Appl Physiol. 2021.
7. 7.Wan W, et al. Mitochondria-derived peptide MOTS-c: effects and mechanisms related to stress, metabolism and aging. J Transl Med. 2023.
8. 8.MOTS-c: A promising mitochondrial-derived peptide for therapeutic exploitation. Front Endocrinol (Lausanne). 2023.
9. 9.MOTS-c, the Most Recent Mitochondrial Derived Peptide in Human Aging and Age-Related Diseases. Int J Mol Sci. 2022.
10. 10.Mitochondrial-encoded peptide MOTS-c prevents pancreatic islet cell senescence and glucose intolerance. Exp Mol Med. 2025.