What is MOTS-c? The Mitochondrial Peptide Explained
A research guide to MOTS-c — the mitochondrial-derived peptide redefining our understanding of metabolic signalling and longevity biology.
MOTS-c (Mitochondrial Open Reading Frame of the 12S rRNA-c) is a 16 amino acid peptide encoded within the mitochondrial genome — specifically within the 12S ribosomal RNA gene. Discovered in 2015, it represents a paradigm shift in our understanding of mitochondria: rather than being purely passive energy factories, mitochondria can directly communicate with the cell nucleus and regulate whole-body metabolism through peptide signalling. MOTS-c is considered one of the most exciting discoveries in longevity and metabolic biology of the past decade.
What Makes MOTS-c Unique?
Unlike nuclear-encoded peptides, MOTS-c is encoded in mitochondrial DNA — making it part of a recently discovered class of peptides called mitochondrial-derived peptides (MDPs). This origin is significant: it suggests that mitochondria have their own communication system for responding to metabolic stress, ageing, and energy demand.
MOTS-c circulates in the bloodstream and can translocate to the cell nucleus in response to metabolic stress, directly regulating gene expression — a capability previously unknown for mitochondrially-encoded peptides.
Mechanism of Action
MOTS-c’s primary mechanism involves AMPK (AMP-activated protein kinase) activation — the master regulator of cellular energy homeostasis. AMPK acts as a cellular fuel gauge: when energy is low, AMPK activation triggers pathways that increase energy production and decrease energy consumption.
- AMPK Activation: MOTS-c activates AMPK, stimulating glucose uptake, fatty acid oxidation, and mitochondrial biogenesis.
- FOXO1 Regulation: MOTS-c modulates FOXO1 transcription factor activity, influencing genes related to insulin sensitivity and metabolic homeostasis.
- Folate Cycle Disruption: Research has identified that MOTS-c works partly by inhibiting the folate cycle in mitochondria, triggering an AICAR-dependent AMPK activation pathway.
- Nuclear Translocation: Under metabolic stress, MOTS-c translocates to the nucleus where it regulates the expression of stress-response genes.
Key Research Areas
Insulin Sensitivity and Metabolic Research: MOTS-c has been studied extensively in models of insulin resistance, with research demonstrating its ability to improve glucose uptake in skeletal muscle and reduce lipid accumulation in metabolic disease models.
Exercise Mimetics Research: One of the most intriguing aspects of MOTS-c research is its overlap with exercise-induced metabolic adaptations. Studies have examined whether MOTS-c can replicate some of the metabolic benefits of physical exercise at the cellular level.
Ageing and Longevity: MOTS-c levels decline with age in humans, and research has examined its role in age-related metabolic decline. Its AMPK-activating and mitochondrial biogenesis-promoting properties make it a compound of significant interest in longevity research.
Obesity and Energy Homeostasis: Research has explored MOTS-c’s effects on adipogenesis, thermogenesis, and whole-body energy expenditure in obesity models.
Compound Profile
| Property | Detail |
|---|---|
| Sequence | Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg (MRWQEMGYIFYPRKLR) |
| Molecular formula | C101H152N28O22S2 |
| Molecular weight | 2174.6 g/mol |
| CAS number | 1627580-64-6 |
| Genetic origin | Short open reading frame within the mitochondrial 12S rRNA gene |
| Discovery | Lee, Cohen and colleagues, Cell Metabolism, 2015 |
| Human data | An analogue (CB4211) completed phase 1a/1b testing; no clinical trials of native MOTS-c |
Key Published Research
- Discovery and mechanism (2015): MOTS-c inhibited the folate cycle and de novo purine synthesis, raising AICAR levels and activating AMPK. In mice it prevented diet-induced obesity and insulin resistance.1
- Longevity genetics (2015): A MOTS-c variant caused by the mitochondrial m.1382A>C polymorphism was associated with exceptional longevity in a Japanese population.2
- Nuclear signalling (2018): Under metabolic stress, MOTS-c moved into the nucleus and regulated antioxidant-response genes in cooperation with NRF2 — direct evidence of mitochondria-to-nucleus peptide signalling.3
- Exercise and ageing (2021): Exercise increased endogenous MOTS-c in human skeletal muscle and plasma, and late-life MOTS-c treatment improved physical capacity in old mice.4
Regulatory & Research Status (2026)
- April 2026: MOTS-c was one of twelve peptides removed from the US FDA’s Category 2 compounding list.
- July 2026: The FDA’s Pharmacy Compounding Advisory Committee voted 7–5 (two abstentions) in favour of adding MOTS-c to the 503A bulks list for proposed obesity and osteoporosis uses. The vote is non-binding; FDA reviewers had flagged a potential immunogenicity risk for some routes of administration.
- Clinical development: The MOTS-c analogue CB4211 was reported as well tolerated in a 2021 phase 1b study in people with obesity and fatty liver, with exploratory metabolic signals. No MOTS-c or analogue trials were registered as active in 2026.
Evidence Quality & Limitations
MOTS-c is a well-validated research target, but efficacy data come almost entirely from mouse and cell models, and there are no human efficacy data for the native peptide. Circulating MOTS-c levels vary with age, exercise and metabolic state, and what these differences mean in humans is not yet clear. Results from the CB4211 analogue cannot be assumed to apply to native MOTS-c.
References
- Lee C, et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab. 2015;21:443–54. PubMed
- Fuku N, et al. The mitochondrial-derived peptide MOTS-c: a player in exceptional longevity? Aging Cell. 2015;14:921–3. PubMed
- 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;28:516–24. PubMed
- Reynolds JC, et al. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nat Commun. 2021;12:470. PubMed
