MOTS-c is an unusual peptide, because it is encoded not by the nucleus of the cell but by the mitochondrion’s own DNA. It is 16 amino acids long and switches on the enzyme AMPK, the cell’s energy sensor, which is how it affects glucose handling and insulin sensitivity. In mice it behaves like exercise delivered by injection: it protects against diet-induced obesity and restores in old animals the insulin sensitivity of young ones. In humans those effects have not been studied after administration. There is no approved clinical use, MOTS-c is a research substance, and in sport it is banned all year round.
Where does MOTS-c come from?
Most peptides in the body are made from instructions written in the DNA of the cell nucleus. MOTS-c belongs to a narrow group of peptides of mitochondrial origin, encoded inside the 12S rRNA gene in mitochondrial DNA. It has 16 amino acids, and its first 11 residues are strongly conserved across 14 species, humans and mice among them. The discovery of this peptide in 2015 introduced the idea that mitochondria not only produce energy but also send out signalling molecules of their own.
What does MOTS-c do in the cell?
MOTS-c switches on AMPK, an enzyme that acts as a sensor of the cell’s energy level. Through AMPK the peptide increases the entry of glucose into cells. Under metabolic stress MOTS-c can move into the cell nucleus and bind to factors that transcribe genes. It then changes which genes are active. That is how it works as a signal of a hormonal character, restoring metabolic balance, rather than as an ordinary product of metabolism.
What did the studies in mice show?
Studies in mice gave a consistent picture of metabolic benefit. Giving MOTS-c prevented obesity in animals fed a high-fat diet. After seven days of dosing, old mice had the insulin sensitivity of young ones. Blood MOTS-c rises after exercise, in one measurement by about twelvefold, and is lower in older people, by 11 to 21 per cent compared with the young. That is where the label of an exercise-mimicking peptide came from.
What is known about MOTS-c in humans?
In humans little is known, and mostly from observation rather than from giving the peptide. It has been confirmed that blood MOTS-c rises with exercise and falls with age. There is, however, no completed clinical trial of giving unmodified MOTS-c. A longer-acting analogue designated CB4211 went through early phases of testing, but its phase 2 was discontinued. The authors of a 2023 review write plainly that no method of using MOTS-c in clinical practice has been developed. Nor is it clear how the peptide enters cells without being broken down on the way. The context of metabolism and body weight is developed in the article on the incretins and GLP-1, and the muscle axis in the article on muscle peptides.
What is the legal and sporting status of MOTS-c?
MOTS-c has no FDA or European Medicines Agency authorisation and is not an accepted treatment for weight loss, ageing, metabolic disease or performance. It is sold as MOTS-c, a reagent for research, and independent analyses detect contamination or mislabelling in about 30 per cent of grey-market products. On the WADA prohibited list MOTS-c appears in group S4, among metabolic modulators and AMPK activators. The ban applies all year, and a therapeutic use exemption is not possible, because no approved indication exists. More on the legal categories is in the article on the legal status of peptides and on the legal warning page.
Frequently asked questions
What is MOTS-c?
A peptide of 16 amino acids encoded not in the cell nucleus but in mitochondrial DNA, within the 12S rRNA gene. It belongs to the peptides of mitochondrial origin, discovered relatively recently.
How does MOTS-c act on metabolism?
It switches on the enzyme AMPK, the cell’s energy sensor. Through AMPK it increases glucose uptake, and under metabolic stress it enters the cell nucleus and affects the activity of genes.
Is MOTS-c exercise in an injection?
That is a label from studies in mice, in which MOTS-c produced metabolic effects similar to training. In humans this has not been tested after giving the peptide.
Are there studies of MOTS-c in humans?
There is no completed trial of giving unmodified MOTS-c. A longer-acting analogue, CB4211, went through early phases, but its phase 2 was discontinued.
Can MOTS-c be used in sport?
No. MOTS-c is on the WADA prohibited list in group S4 as an AMPK activator, banned all year, with no possibility of a therapeutic use exemption.
Where this information comes from
The mitochondrial origin within the 12S rRNA gene, the 16 amino acid length, the conservation of the first 11 residues across 14 species and the 2015 discovery come from the original publications on MOTS-c. The AMPK mechanism, the nuclear translocation under metabolic stress, the prevention of diet-induced obesity, the restoration of insulin sensitivity in old mice after seven days, the roughly twelvefold rise after exercise and the 11 to 21 per cent lower level in older people come from the same body of work. The discontinued phase 2 of CB4211 comes from the trial registry, and the statement that no clinical method of use has been developed from a 2023 review. The group S4 listing comes from the WADA prohibited list. These sources were checked on 6 September 2026.