MOTS-c Guide: Evidence & Sourcing

MOTS-c at a glance

What it is

A 16-amino-acid peptide encoded by a short open reading frame inside the mitochondrial 12S rRNA gene - one of the mitochondrial-derived peptides, alongside humanin. C101H152N28O22S2, average molecular weight approximately 2,174.6 Da, PubChem CID 146675088.

Where the name comes from

Mitochondrial Open reading frame of the Twelve S rRNA type-c. It is descriptive of the gene it was found in, not of what it does.

Discovered

Lee C et al., Cell Metabolism 2015 - the paper that identified the reading frame, named the peptide and established its metabolic effects in mice.

Established mechanism

Inhibits the folate cycle and the de novo purine biosynthesis tethered to it, which raises AICAR and activates AMPK. Under metabolic stress it also translocates into the nucleus and regulates nuclear gene expression, including antioxidant-response-element genes, in an AMPK-dependent way - making it a genuine mitochondrial-to-nuclear signal.

Primary tissue

Skeletal muscle. This is where the discovery paper located its main action and where the exercise literature concentrates.

The exercise finding

Exercise induces endogenous MOTS-c in human skeletal muscle and in circulation - that part is human data. The performance and healthspan effects of giving MOTS-c are mouse data. Keeping those two apart is the single most common error in writing about this compound.

Human trial status

None this guide is prepared to cite. A registry entry previously listed here as the first registered interventional trial, NCT07505745, was withdrawn on 2026-08-26 on provenance grounds: it carries no results and no publication, and the account that filed it also filed a TB-500 entry whose own summary calls itself a fictional example record.

Regulatory status

Not approved by FDA or any comparable regulator for any indication. Sold and discussed for research and educational use only. Not specifically named on the WADA Prohibited List as of this writing, which is not the same as being permitted - verify current status directly.

Educational reference. This page does not publish dose ranges or reconstitution arithmetic.

What it is / mechanism

The interesting thing about MOTS-c is where it was found. Mitochondria carry their own small circular genome, a leftover of the bacterial ancestry of the organelle, and for decades that genome was described as containing 37 genes: 13 protein-coding, 22 transfer RNAs and 2 ribosomal RNAs. The ribosomal RNA genes were understood as structural - they make the RNA scaffolding of the mitochondrial ribosome and nothing else. Then humanin was identified inside the 16S rRNA gene, which raised the obvious question of whether other short open reading frames were hiding in mitochondrial DNA. Lee and colleagues went looking in the 12S rRNA gene and found one, encoding a 16-residue peptide they named MOTS-c: mitochondrial open reading frame of the twelve S rRNA type-c. The name describes the address, not the function. That origin is not trivia. It means MOTS-c is an endogenous molecule that circulates in human plasma, that is expressed in tissues alongside mitochondria, and whose levels decline with age. It also means the mitochondrial genome encodes signalling factors rather than only structural and respiratory components - a genuine change in how mitochondrial-nuclear communication is understood, and the reason this peptide gets attention in aging biology rather than only in metabolism. The mechanism established in the discovery paper is specific and slightly counterintuitive. MOTS-c targets skeletal muscle, and its cellular action is inhibition of the folate cycle and of the de novo purine biosynthesis pathway tethered to it. Blocking that pathway causes AICAR - an intermediate in purine synthesis - to accumulate, and AICAR is an AMPK activator. So MOTS-c activates AMPK indirectly, through a metabolic intermediate, rather than by binding a receptor. AMPK is the cell's low-energy sensor: when it is activated, the cell shifts toward glucose uptake, fatty-acid oxidation and catabolic energy generation and away from anabolic synthesis. In mice, MOTS-c treatment prevented both age-dependent and high-fat-diet-induced insulin resistance, and prevented diet-induced obesity. The second mechanistic layer arrived in 2018 and is the more conceptually significant one. Kim and colleagues showed that under metabolic stress - specifically glucose restriction - MOTS-c translocates from the cytoplasm into the nucleus, where it regulates a broad set of nuclear genes in an AMPK-dependent manner. Among the genes it influences are those carrying antioxidant response elements, and MOTS-c was found to interact with the stress-responsive transcription factors that regulate them, including NRF2. The framing the authors gave it is worth quoting in substance: the nuclear genome was already known to regulate the mitochondrial genome, and this demonstrates regulation running the other way, with the two genomes having co-evolved to encode factors that cross-regulate each other. A peptide encoded in mitochondrial DNA that physically enters the nucleus and changes nuclear transcription is a retrograde signal in the strongest sense. The exercise connection follows from the stress-response logic. MOTS-c expression rises in skeletal muscle, in the circulation and in the hypothalamus in response to exercise, which fits a peptide whose trigger is metabolic stress and whose action is AMPK-linked. This is the basis of the mitohormesis framing that MOTS-c is usually discussed under: low levels of mitochondrial stress produce adaptive responses, and mitochondrial-derived peptides are among the messengers carrying those responses beyond the organelle. Exogenous MOTS-c has also been reported to stimulate thermogenesis in subcutaneous white adipose tissue in animal work, which is a separate arm from the muscle effects. A genetic strand exists and is routinely overstated. Fuku and colleagues noted that a polymorphism in the MOTS-c-encoding region of mitochondrial DNA, m.1382A>C, is specific to Northeast Asian populations, and proposed that it might be among the mechanisms contributing to Japanese longevity. That paper is explicitly a hypothesis - its own title ends in a question mark and its text says more research is needed. It is frequently cited on commercial pages as though it demonstrated that a MOTS-c variant causes exceptional lifespan, which it does not. What none of this mechanistic work establishes is that administering MOTS-c does anything in a human being. That question has only just been put to a controlled test, and the test is still running.

Researched effects

The effects reported for MOTS-c divide cleanly into two categories that are constantly conflated, so it is worth separating them explicitly before listing anything. Category one is what endogenous MOTS-c does, and here there is genuine human data. Acute high-intensity exercise raises MOTS-c concentrations in human skeletal muscle and in plasma - this has been measured in people, not inferred from mice. Circulating MOTS-c declines with age. That is the human evidence base, and it is observational: it establishes that MOTS-c is an exercise-responsive endogenous peptide whose levels fall over a lifespan. Category two is what happens when MOTS-c is administered, and that column is entirely animal work. The headline results are substantial within that limit. Reynolds and colleagues reported that MOTS-c significantly enhanced physical performance in mice at three ages - young at 2 months, middle-aged at 12 months and old at 22 months - and, in the finding that gets quoted most, that treatment initiated in late life at 23.5 months on an intermittent schedule of three times per week increased both physical capacity and healthspan. The same paper documented effects on nuclear gene expression relating to metabolism and proteostasis, on skeletal muscle metabolism, and on myoblast adaptation to metabolic stress. The metabolic results from the discovery paper sit alongside these: prevention of age-dependent and diet-induced insulin resistance and of diet-induced obesity in mice. It is worth noticing where the community's three-times-weekly dosing convention comes from, because almost nobody says. It comes from that mouse study's intermittent late-life schedule. There is no human study establishing that frequency, or any other. Beyond muscle and metabolism, the animal literature has broadened in directions that are rarely mentioned on commercial pages. MOTS-c has been reported to relieve hyperglycaemia and insulin resistance in a mouse model of gestational diabetes, improving glucose tolerance and insulin sensitivity and protecting pancreatic beta cells from chemical injury. And a 2024 study reported that MOTS-c levels are reduced in serum and tumour tissue from ovarian cancer patients and associated with worse prognosis, with exogenous MOTS-c inhibiting proliferation, migration and invasion in ovarian cancer cells through a LARS1 and USP7 mechanism, and showing anti-tumour effect without systemic toxicity in vivo. These are single-group findings in specific models and are included here for completeness rather than as anything actionable. What the training literature does not show is worth stating as clearly as what it does. Whether regular exercise training produces a chronic change in MOTS-c levels - as opposed to the acute post-exercise spike - is genuinely unresolved, with conflicting results that appear to depend on the mode, duration and intensity of the training programme and on participant characteristics. Anyone reading a confident claim that training raises baseline MOTS-c is reading past a disagreement in the literature. And until very recently, the field's own summary of the translational position was blunt: reviews as recent as 2023 stated that no effective method of applying MOTS-c in the clinic had been developed. That is the honest backdrop, and the trial registry does not currently change it - the evidence section sets out why the entry once cited here was withdrawn. Nothing here is a claim that MOTS-c treats, prevents or improves any condition in people, and nothing here is medical advice.

Research timeline

Dated milestones taken from the primary records: the molecule's discovery, its first registered human study, the trials that shaped the evidence and the regulatory decisions. Each entry links to the record it comes from.

1. Mar 3, 2015Changhan Lee's group at the University of Southern California reports a 16-amino-acid peptide encoded inside the mitochondrial 12S rRNA gene, names it MOTS-c, and shows that it prevented diet-induced obesity and insulin resistance in mice. PMID 25738459
2. Jan 19, 2021A study of 27,527 people in three cohorts links an East Asian mitochondrial variant that swaps one amino acid in MOTS-c (K14Q) to more type 2 diabetes in men but not women; in mice the variant peptide lost the original's effect on weight and glucose tolerance. PMID 33468709
3. Aug 5, 2021The first study, by its authors' account, of circulating mitochondrial-derived peptides after a single exercise session in people finds that endurance exercise raised blood humanin, while MOTS-c showed only a non-significant trend upward. PMID 34351816
4. Oct 30, 2021A Japanese study of muscle biopsies, strength tests and 721 athletes against 873 controls associates the same K14Q variant with muscle fibre composition and muscular performance. PMID 34728329
5. Jul 23, 2026MOTS-c goes before FDA's Pharmacy Compounding Advisory Committee for the pharmacy-compounding (503A) list, evaluated for obesity and osteoporosis; FDA's briefing document concludes that the balance of criteria weighs against listing it. No minutes or vote were posted by 4 Oct 2026. FDA · PCAC briefing document, Jul 23–24, 2026

Records checked Oct 4, 2026

Claims at a glance

The claims most often made about this compound, each with the strongest kind of evidence we found for it. The grade says what was studied, not whether the claim is true; the line beside it says what that study showed.

• Improves insulin sensitivityAnimal studies only. In the 2015 discovery paper it prevented diet- and age-related insulin resistance in mice; no study has given it to people. PMID 25738459
• Prevents weight gain and obesityAnimal studies only. Mice on a high-fat diet gained less weight; fat loss has never been measured in a person given MOTS-c. PMID 25738459
• Mimics the effects of exerciseAnimal studies only. Exercise raises the body's own MOTS-c in people; giving it improved physical performance only in mice. PMID 33473109
• Slows ageingAnimal studies only. Treatment begun late in life improved physical capacity in old mice; no study has measured ageing or lifespan in people. PMID 33473109
• Has been tested in peopleNo study found. The human studies found measure the body's own MOTS-c, for example after exercise; none gave it to anyone. PMID 34351816

The reasoning behind each grade, study by study, is in this guide's Benefit & Outcome Review.

Grades checked Oct 5, 2026

Half-life & pharmacokinetics

No published human pharmacokinetic study reports a half-life for MOTS-c. Targeted searches for pharmacokinetics, half-life and plasma clearance of this peptide return nothing, and there is no approved product whose label would supply the figure. Any specific number quoted for MOTS-c half-life is not traceable to a measurement in people. What can be said, carefully, comes from two directions. The first is structural. MOTS-c is a 16-residue unmodified peptide with no half-life-extending modification of the kind attached to peptides designed for weekly administration - no fatty-acid acylation, no PEGylation, no albumin-binding moiety. Peptides of that description are generally cleared on the order of minutes to a few hours by peptidase degradation and renal filtration. This is a structural expectation, not a measurement, and it should be labelled as one. The second is behavioural, and more interesting. The endogenous peptide's dynamics have been observed in humans in the exercise context: MOTS-c rises in skeletal muscle and plasma after acute high-intensity exercise, which is a stimulus-response pattern on the timescale of a training session rather than of days. Whether chronic training shifts baseline levels is unresolved in the literature. Neither observation gives a clearance rate, but both are consistent with a molecule that responds and resolves quickly rather than persisting. The most honest framing of the frequency question is therefore that the three-times-weekly convention in community protocols does not rest on a duration-of-action measurement at all. It rests on the schedule used in one mouse healthspan experiment. That may or may not be a sensible cadence for a peptide with these properties; what it is not is a pharmacokinetically derived interval, and it should not be presented as one.

Storage & handling

• Lyophilised and unopened: store cold and dark. Long-term storage is typically described at -20 C in a freezer, with refrigeration generally described as adequate for shorter periods. Keep the vial in its carton, since peptides in general are light-sensitive.
• After reconstitution with bacteriostatic water: refrigerate at roughly 2-8 C. The usable window commonly reported in research settings is around two to four weeks; the benzyl alcohol in bacteriostatic water is what makes a multi-withdrawal window possible at all, by suppressing microbial growth between entries.
• Do not freeze a reconstituted vial. Freeze-thaw cycling is a recognised degradation route for peptides in solution and is the most common avoidable handling error.
• Choose the reconstitution volume before mixing, not after: once the vial is reconstituted, its concentration cannot be changed.
• Add bacteriostatic water slowly down the inside wall of the vial rather than onto the powder, swirl rather than shake, keep the stopper clean and use a fresh needle for each withdrawal. Mechanical agitation causes peptide aggregation, and no preservative compensates for repeated entry with a contaminated needle.

Evidence File

The MOTS-c Evidence File: 254 Papers, Nine Registry Records, and Not One Published Human Dose

MOTS-c is unusual among research-market compounds in that its scientific literature is genuinely large and genuinely good — 254 PubMed records, a 2015 discovery paper in a major journal, a real mechanism, and a naturally occurring human genetic variant that has been studied in its own right. What that literature never does is give the peptide to a person. This file separates the two questions the market runs together: what is known about MOTS-c as a molecule your own mitochondria make, and what is known about injecting it. The first has a decade of work behind it. The second is empty — and the one registry record that appeared to fill it has been withdrawn as evidence by this guide, on provenance grounds set out in full below. Every search is named so that every claim here can be reproduced rather than taken on trust.

• 9 registry records found across 4 named search terms
• 0 of the 9 establish that MOTS-c has been given to anyone
• 254 PubMed records; 5 tagged as clinical trials; 0 of those 5 gave the peptide
• 1 record withdrawn — its filing account has 8, three self-declared fictional

Sourcing File

The MOTS-c Sourcing File: A Sequence That Verifies Itself, Two Methionines, and a Variant Routine Mass Spec Cannot See

MOTS-c is one of the more checkable peptides in this library, and one of the easier ones to get quietly wrong. Its sixteen-residue sequence reproduces its published molecular formula exactly, which means a reader with a certificate in front of them can verify the identity claim arithmetically rather than trusting it — this file shows that calculation worked through. It also has two specific liabilities that generic COA advice will not catch: a pair of methionine residues that oxidise and shift the mass in predictable steps, and a naturally occurring human sequence variant that differs from the reference peptide by four hundredths of a dalton, which is comfortably inside the error of the mass spectrometry most suppliers actually run.

• Sequence MRWQEMGYIFYPRKLR verified against PubChem formula — exact match
• 2 methionines: +15.99 Da per oxidation, two steps possible
• K14Q variant differs by 0.043 Da — 20 ppm on a 2,174 Da peptide
• 0 FDA-approved products; no pharmacopoeial monograph to test against

Benefit & Outcome Review

The MOTS-c Benefit and Outcome Review: Every Marketed Claim Against What Was Measured, and in What Species

This review takes the claims made for MOTS-c one at a time and asks the same four questions of each: what was measured, in whom or in what, how large the effect was, and whether the compound was administered or merely observed. That last question does most of the work here. MOTS-c has an unusually respectable scientific literature, and an unusually wide gap between what that literature establishes about the peptide your mitochondria make and what is claimed for the peptide in a vial. Where a claim is supported, this review says so plainly. Where the supporting evidence is an association running in the opposite direction to the claim, it says that too.

• 5 marketed claims assessed against the primary record
• 0 rest on published human administration data
• 1 is supported by evidence pointing the opposite way
• 0 have a human trial pending — the one on the register was withdrawn

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Quick answers about guide scope, access, and educational use context.