Lee C, Zeng J, Drew BG, et al. (2015). The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab, 21(3):443-54.
What is MOTS-c?
Mitochondria are the power plants inside your cells, and they carry their own small set of DNA. In 2015, researchers at the University of Southern California found a hidden instruction in that DNA for a short peptide, just 16 amino acids long. They named it MOTS-c [1].
That was a surprise. Mitochondrial DNA was mostly thought of as a blueprint for the cell’s energy machinery, not for signals that travel around the body. MOTS-c appears to act like a metabolic hormone [2], and its main target seems to be skeletal muscle [1].
Today synthetic MOTS-c is sold online as an injection, marketed for metabolism, weight loss, and physical performance. It isn’t part of any FDA-approved drug [S1].
How might it work?
- Flipping a metabolic switch. In cells, MOTS-c slows a chemical pathway called the folate cycle. That in turn switches on AMPK, an enzyme that acts as the cell’s energy sensor [1]. Because some of its effects resemble those of exercise, researchers have described it as an “exercise mimetic” [3].
- Talking to the nucleus. When cells are under metabolic stress, MOTS-c travels from the mitochondria into the nucleus and turns on genes, including ones that protect against oxidative damage [4].
- Activating muscle. MOTS-c binds directly to an enzyme called CK2. Curiously, it boosts CK2 in muscle but dampens it in fat [5].
- Fighting germs. A 2026 study found that MOTS-c can kill bacteria, including the drug-resistant superbug MRSA. It neutralized an MRSA infection in mice [6].
What has research found?
In animals
- Metabolism: In mice, MOTS-c prevented obesity and insulin resistance caused by a high-fat diet, as well as insulin resistance that comes with age [1]. It also prevented weight gain and insulin resistance after the ovaries were removed, a model of menopause [7].
- Physical performance and aging: MOTS-c improved physical performance in young, middle-aged, and old mice. Even when treatment started late in life, three times a week, it increased physical capacity and markers of healthy aging [8].
- Muscle: In obese mice, MOTS-c reduced signals that drive muscle wasting [2]. When a leg was immobilized in a cast, mice lost about 5% of their muscle with MOTS-c, compared with about 15% without it [9].
- Diabetes: In mice prone to type 1 diabetes, MOTS-c protected insulin-making cells from immune attack [10]. It also slowed the aging of those cells in other diabetes models [11].
- Not every finding is positive: In human stem-like cells taken from fat, MOTS-c activated metabolism but slowed cell growth, raised markers of cell aging, and weakened the cells’ ability to repair damaged kidneys in mice [12]. A 2018 commentary also noted a report that MOTS-c may increase inflammatory signals from aging cells [13].
In people (natural MOTS-c)
- Exercise: Exercise raises natural MOTS-c levels in muscle and blood [8]. Results vary, though. In one study, a single endurance workout produced only a trend toward higher levels [14]. In another, a 16-week exercise program raised levels in non-Hispanic White breast cancer survivors but not in Hispanic survivors [15].
- Genes: Some people in Northeast Asia carry a natural variant that makes MOTS-c less active. Researchers first proposed it might help explain Japanese longevity [16]. A later study of 27,527 people, however, found that men with the variant had more type 2 diabetes, especially if they were inactive [17]. Carriers also had more fast-twitch muscle fibers, and the variant was more common in sprint and power athletes [3].
- Disease: People with type 1 diabetes [10] and type 2 diabetes [11] had lower blood levels than healthy people. Findings in obesity conflict: one small study found no difference between lean and obese people [18], while another found higher levels in obesity [19].
- As a treatment: No studies have given synthetic MOTS-c to people [S1].
How strong is the evidence?
| What we know so far | What we still don’t know |
|---|---|
| It’s a natural peptide made from mitochondrial DNA, discovered in 2015 [1] | Whether taking synthetic MOTS-c helps people, because it has never been tested in humans [S1] |
| Mouse studies consistently show benefits for metabolism and muscle [1, 8] | The right dose and which organs it affects, because dose-response studies are missing [S1] |
| Exercise raises natural levels in people [8] | How much MOTS-c people actually have, because lab tests disagree widely [20] |
| Genetic studies link a weaker form of MOTS-c to diabetes risk in men [17] | Long-term safety and the risk of immune reactions [S1] |
A few more things to keep in mind:
- Measuring it is tricky. An anti-doping lab couldn’t confirm the blood levels reported by a common commercial test [20], and average levels reported in different studies vary several hundredfold [18, 19, 20].
- Much of the research comes from one team with a financial stake. The scientists who discovered MOTS-c are consultants to and shareholders in CohBar, the company that licensed it [5, 8].
- Its effects depend on context. The same peptide had opposite effects in different tissues and cell types [5, 12].
Safety: what we know
- No human safety data. FDA found no information on synthetic MOTS-c given to people by any route, and said it was particularly concerned about that gap [S1].
- Immune reactions: FDA can’t rule out immune reactions caused by impurities or clumping, especially with injections [S1].
- Unexpected effects: In some human cells, MOTS-c increased markers of aging and inflammation [12].
- Unregulated products: Injectable peptides sold directly to consumers operate largely outside regulatory oversight, and rigorous human safety data are scarce [21].
Legal status
- Not an approved medicine. It isn’t part of any FDA-approved drug [S1].
- United States: FDA’s reviewers recommended against letting pharmacies prepare (compound) MOTS-c, citing the lack of any human data. An FDA advisory panel voted in favor in July 2026, 7 to 5 with 2 abstentions, and a final decision is still pending [S1, S2].
- Sports: Banned at all times by the World Anti-Doping Agency (WADA) as a metabolic modulator [S3], and anti-doping labs have developed a test for it [20].
The bottom line
MOTS-c is one of the most intriguing discoveries in recent biology: a hormone-like signal hidden in our mitochondrial DNA, boosted by exercise, and linked to metabolism, muscle, and even immunity. In mice, it pushed back against several signs of metabolic and physical aging.
But the field is barely a decade old, and synthetic MOTS-c has never been tested in people. Careful human trials, along with reliable ways to measure it, are the next steps toward finding out whether this mitochondrial messenger can live up to its promise.