MOTS-c

A 16-amino-acid peptide encoded by a short stretch of DNA inside the mitochondria, the parts of the cell that make energy. First described in 2015 and sold since then as a research peptide, often with the claim that it mimics exercise.

Sold as

Sold for injection under the skin. There is no approved way to take it.

Legal status in the EU

Not approved as a medicine in the EU or anywhere else. MOTS-c is not named on the doping list, but it falls under section S0, which bans any pharmacological substance without current approval from a national authority for human therapeutic use. SVT's 2026 investigation counted MOTS-c among the banned substances found in products sold to Swedish consumers.

According to the original paper, skeletal muscle is the main target. Inside cells, MOTS-c blocks a metabolic pathway in a way that activates AMPK, a master switch for cellular energy. In mice, treatment prevented both age-related and diet-induced insulin resistance, and diet-induced obesity.

Part of the bodyWhat happensHow it is knownKind of evidence

Your own MOTS-c, after hard exercise

This is the only part of the story measured in people, and it is about the peptide a body makes for itself, not about an injection. After one hard session on an exercise bike, the amount of MOTS-c inside muscle rose sharply and was still raised four hours later. The amount in the bloodstream rose far less and was back to normal within four hours.

Measured in 10 sedentary healthy men, average age about 24, across a single cycling session, with muscle samples taken before, straight after, and four hours later. Muscle MOTS-c rose 11.9-fold; blood MOTS-c rose about 1.5 to 1.6-fold and then fell back.

Measured in people

Source [07]

Muscles, and how long you can keep going

In mice, an injection shortly before a treadmill test made them run for longer and further than mice given salt water. Old mice given it three times a week, starting late in life, kept more grip strength and a longer stride. Nothing of this kind has ever been tested in a person.

Measured only in rodents: young (2 months), middle-aged (12 months) and old (22 months) mice on a treadmill; a separate group of male mice treated three times a week from 23.5 months of age; and untrained female mice given one injection ten minutes before a run. FDA's 2026 review found no human study of physical performance.

Only seen in animals

Source [07]Source [08]Source [09]

Blood sugar and insulin

This is the effect the peptide was first described for. In mice, treatment made muscle respond better to insulin, the hormone that moves sugar out of the blood. In mice made obese on a fatty diet, three days of treatment roughly halved blood sugar compared with mice injected with water.

Measured in mice only: adult male mice during an insulin infusion test, 12-month-old mice treated for seven days, and 17-week-old obese mice treated twice a day for three days. FDA searched PubMed, Embase, Cochrane and ClinicalTrials.gov for its 2026 review and found no study of blood sugar in people given MOTS-c.

Only seen in animals

Source [01]Source [09]

Body weight and fat

Mice fed a very fatty diet and injected daily gained less weight than mice on the same diet given the injection fluid alone. They also burned more energy and stored less fat in the liver. Female mice whose ovaries had been removed, a way of copying the weight gain that follows the menopause, also gained less.

Measured only in mice. Adult male mice on a diet with 60 per cent of its calories from fat were treated daily for eight weeks. Female mice were treated daily for twelve weeks after their ovaries were removed. No human study of body weight on MOTS-c has been published.

Only seen in animals

Source [01]Source [09]

Bones

Rat bone stem cells grown in a dish with MOTS-c switched on more of the genes cells use to build bone, and laid down more mineral. In mice, plastic particles placed under the scalp cause the skull bone underneath to dissolve. Injecting MOTS-c into that spot each day for a week reduced the damage and the number of bone-dissolving cells.

Measured in rat cells in a dish over seven days and in adult male mice given local injections for seven days. Bone thinning was one of the uses MOTS-c was nominated for in the United States. FDA found no human study of it, and no measurement of how much produces how much effect in any animal.

Only seen in animals

Source [09]

What happens to it in the blood

Nobody knows how much of an injection survives. When MOTS-c was added to human blood in a tube it was cut apart quickly into shorter fragments. The researchers said the breakdown did not need long to happen. No study has ever measured what becomes of it inside a living person.

Measured in human blood in a test tube at body temperature, sampled at 15 and 60 minutes, in a 2019 method paper written for anti-doping laboratories. FDA's 2026 review found no study in any species of how the peptide is absorbed, spread or cleared. It said it remains open whether an injection can produce useful amounts in a person at all.

Only seen in a dish, not in a body

Source [09]Source [10]

The original paper (Lee et al., Cell Metabolism 2015) identified the peptide and reported cell experiments and treatment experiments in mice. No controlled human study of MOTS-c treatment has been published. A randomised, double-blind, placebo-controlled phase 2 study in people with prediabetes and overweight or obesity (NCT07505745, Hudson Biotech, 120 planned) started in February 2026 and has no results.

What was measuredWhat happenedIn whomHow it is known

Body weight, in mice

Treated mice weighed about 20 per cent less than mice given the injection fluid alone, and stored less fat in the liver.

Adult male CD-1 mice on a diet with 60 per cent of its calories from fat, injected daily for 8 weeks.

Only seen in animals

Source [01]Source [09]

How well insulin worked, in mice

Treated mice needed about 30 per cent more sugar infused than mice given the injection fluid. The sugar was infused to hold their blood sugar steady while insulin was running. That is the standard laboratory way of saying insulin was working better.

Adult male CD-1 mice, treated daily.

Only seen in animals

Source [01]Source [09]

Blood sugar, in obese mice

About half the blood sugar of mice injected with water on the same schedule.

17-week-old male C57BL/6J mice made obese on a high-fat diet, treated twice a day for 3 days.

Only seen in animals

Source [09]

How far and how long old mice ran

Treated old mice ran about twice as long and 2.16 times as far as untreated old mice. 17 per cent of them reached the fastest stage of the treadmill test, against none of the untreated ones.

Old mice, 22 months, given MOTS-c and compared with untreated old mice on a treadmill.

Only seen in animals

Source [07]

How long mice lived

Half the treated mice were still alive at 970 days, against 912 days for mice given the injection fluid. The longest-lived treated mice reached 1,120 days, against 1,047 days. The authors called this a trend rather than a result, and said larger groups of mice would be needed to confirm it.

Male C57BL/6N mice, treatment started at 23.5 months of age and given three times a week.

Only seen in animals

Source [07]Source [09]

No published human safety data exists. Activating AMPK affects energy metabolism broadly, and the consequences of switching it on with a drug over a long period in healthy people are unknown. These products are made without oversight: in a French analysis of 110 preparations seized from the black market among bodybuilders (Fabresse et al., Forensic Science International 2021), 25 of 75 medicines (33 per cent) were incorrectly dosed and 24 of 75 (32 per cent) were counterfeit — they did not contain what the label said.

EffectWhat it feels likeHow often

An immune reaction to the injected peptideSerious

The US regulator could not rule this out in its 2026 review. A sixteen-amino-acid peptide can provoke the immune system into making antibodies against it, and injecting under the skin provokes more of a response than injecting into a vein. There is no published information on the impurities in these powders, or on whether the peptide clumps together, and clumping makes an immune reaction more likely. FDA noted that reactions of this kind range from antibodies with no symptoms at all to reactions that are life-threatening.

Not measured. There is no clinical study of MOTS-c in people, so nobody has counted how often this happens or whether it happens at all.

Source [09]

Whatever else is in the vialSerious

MOTS-c has no quality standard in the US, European or Japanese pharmacopoeias, and is not part of any approved medicine. FDA judged both the free base and the acetate salt to be not well characterised. It could find no published data on their impurities, on clumping, or on the level of bacteria and bacterial toxins in them. Different sellers also use the same name for chemically different substances.

Not counted for MOTS-c specifically. A French forensic study analysed 110 products seized from the black market among bodybuilders between January 2016 and December 2019. Of the 75 medicines in it, 24 (32 per cent) contained something other than what the label said. Another 25 of the 75 (33 per cent) contained the wrong amount.

Source [04]Source [09]

Everything else — nothing has ever been counted

An empty database is not a clean safety record. Nobody who buys a peptide online is inside any reporting system, and pharmacies compounding under the US rule generally do not report side effects to FDA either. The blank means nobody is collecting, not that nothing happened.

Not measured. FDA searched its adverse event database for MOTS-c twice, covering everything up to 9 March 2025, and found no reports at all.

Source [09]

What people report

• Whether an injection puts any usable amount of MOTS-c into a person's muscle, or how long it stays — no study of absorption or clearance exists in any species.
• Whether it changes blood sugar, body weight or endurance in a human being at all.
• What repeated use does over months: FDA found no repeat-dose animal toxicity study of any length.
• Whether it damages DNA — no genetic toxicity testing has been done.
• Whether it affects fertility, pregnancy or an unborn child — no study exists in any species.
• Whether it raises or lowers cancer risk — no cancer study has been done.
• Which organs it acts on: the molecule it binds to is still unidentified, which FDA said makes it impossible to predict what would be affected.
• How much produces how much effect — dose against response has never been measured, even in rodents.
• Whether people injecting it develop antibodies against it, and whether those antibodies would also attack the MOTS-c their own mitochondria make.

Has anyone ever been given MOTS-c in a study?

Not in any study that has been published. FDA searched PubMed, Embase, the Cochrane library, ClinicalTrials.gov and its own adverse event database in 2026. It stated that it identified no clinical studies and no human exposure data for MOTS-c by any route. The first randomised trial started on 2 February 2026: 120 adults with prediabetes, meaning blood sugar higher than normal but not high enough to be diabetes, and a body mass index between 27 and 40. One group is given MOTS-c and one a dummy injection, for twelve weeks, with insulin sensitivity measured from a sugar drink test at the end. It is still recruiting, is due to finish in February 2027, and has no results.

Source [02]Source [09]

Is it really "exercise in a syringe"?

That phrase comes from a real finding, but it is a finding about the body, not about the product. In 10 sedentary men, one hard cycling session raised the MOTS-c inside their leg muscle 11.9-fold. What an injection of manufactured MOTS-c does to a person has never been measured. In mice, an injection ten minutes before a treadmill test raised running time by about 12 per cent and distance by about 15 per cent against salt water. Five of six treated mice passed the forty-minute mark, against none of the six controls.

Source [07]Source [08]

What did the FDA decide in July 2026?

MOTS-c was nominated by a compounding pharmacy company, Wells Pharmacy Network. The nominated uses were insulin resistance, obesity, bone thinning, hardened arteries, muscle and fat metabolism, and longevity. The nomination was withdrawn, and FDA reviewed the substance anyway, judging it against two of those uses: obesity and bone thinning. Its written conclusion was that neither MOTS-c nor its acetate salt should go on the list, for four reasons. Neither is properly characterised chemically; there is no record of it being used in compounding; there is no evidence it works; and there is no human or animal safety information. The outside committee met on 23 and 24 July 2026 and voted to recommend it anyway. That account comes from the National Community Pharmacists Association, a trade body for the pharmacies that would be allowed to make it. The advice is not binding on FDA, and FDA had published no minutes or vote record as of 2 August 2026.

Source [09]Source [11]Source [12]

People post blood test results for MOTS-c. Do those mean anything?

Less than they appear to. An anti-doping laboratory measured 20 healthy people twice: once with a commercial antibody kit, and once with mass spectrometry, the slower method that identifies a molecule by weighing its pieces. The kit reported 45.9 to 218.5 nanograms per millilitre. The mass spectrometry could not confirm those levels at all, and the two methods differed considerably. The kit-based literature has been pooled once, across 7 studies and 602 people. It reports MOTS-c lower in people with type 2 diabetes and higher in people with obesity. A separate study of 85 adults, 48 with obesity and 37 of normal weight, used a kit and found no difference between the groups.

Source [10]Source [13]Source [14]

Would it show up in a drugs test?

It is meant to. FDA's review records MOTS-c as a prohibited substance in Global DRO, the reference database athletes use. Global DRO takes those entries from the 2024 World Anti-Doping Agency list of hormone and metabolic modulators. A laboratory method for detecting MOTS-c in plasma, the liquid part of blood, was built and validated against the agency's laboratory standard in 2019. It detects the peptide down to 100 picograms per millilitre, along with four of its breakdown fragments.

Source [09]Source [10]

Each letter represents one amino acid.

1. [01]The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance (Cell Metabolism) (2015)
2. [02]MOTS-c for Improving Insulin Sensitivity in Adults With Prediabetes and Overweight/Obesity (NCT07505745, fas 2, rekryterar) (2026)
3. [03]MOTS-c, PubChem synonymer (H-MRWQEMGYIFYPRKLR-OH)
4. [04]Analysis of pharmaceutical products and dietary supplements seized from the black market among bodybuilders (n=110) (2021)
5. [05]2023 doping list, Antidoping Sweden — S0, non-approved substances (in Swedish) (2023)
6. [06]SVT investigation: peptides contain banned substances — buyers can be prosecuted (in Swedish) (2026)
7. [07]MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis (Nature Communications) (2021)
8. [08]MOTS-c increases in skeletal muscle following long-term physical activity and improves acute exercise performance after a single dose (Physiological Reports) (2022)
9. [09]FDA briefing document, Pharmacy Compounding Advisory Committee, 23–24 July 2026 — evaluation of MOTS-c (free base) and MOTS-c acetate (2026)
10. [10]Development of a mass spectrometry based detection method for the mitochondrion-derived peptide MOTS-c in plasma samples for doping control purposes (Rapid Communications in Mass Spectrometry) (2019)
11. [11]Meeting of the FDA Pharmacy Compounding Advisory Committee, 23–24 July 2026 — meeting page and materials (2026)
12. [12]FDA advisory committee nominates six peptides for pharmacies to compound (National Community Pharmacists Association) (2026)
13. [13]The correlation between mitochondrial derived peptide (MDP) and metabolic states: a systematic review and meta-analysis (Diabetology & Metabolic Syndrome) (2024)
14. [14]MOTS-c levels in individuals with and without obesity and its association with inflammation, insulin resistance and endothelial dysfunction (Archives of Endocrinology and Metabolism) (2025)