MOTS-c

01 · What it is

MOTS-c has the most complete molecular account of any compound in this project and not one interventional human trial.

That combination is unusual enough to be worth stating twice. A named gene of origin. A defined 16-residue sequence. An identified direct binding partner, confirmed in cell-free systems. A mapped signalling cascade with tissue-specific direction. A naturally occurring human variant that abolishes the binding and tracks with disease risk in a population. And nobody has yet given it to a person and measured what happens.

MOTS-c stands for mitochondrial open reading frame of the 12S rRNA type-c. It was reported in 2015 by a group at the University of Southern California, who found a short open reading frame inside the mitochondrial 12S ribosomal RNA gene encoding a 16-amino-acid peptide, and showed that it regulates insulin sensitivity and metabolic homeostasis ¹. Its primary target organ appeared to be skeletal muscle. Its cellular action was traced to inhibition of the folate cycle and the de novo purine biosynthesis tethered to it, leading to AMPK activation. In mice, treatment prevented age-dependent and high-fat-diet-induced insulin resistance and diet-induced obesity ¹. A review from the same group the following year framed the compound as a regulator of muscle and fat metabolism, which is the frame the field has used since ²; later surveys placed it within human ageing and age-related disease ⁸.

The finding that made the field pay attention came three years later. MOTS-c translocates to the nucleus under metabolic stress, in an AMPK-dependent manner, and regulates nuclear gene expression — including genes carrying antioxidant response elements — by interacting with stress-responsive transcription factors such as NRF2 ³. Before that paper, the nuclear genome was not known to be actively controlled by any factor encoded in mitochondrial DNA. This is a peptide written in the mitochondrial genome that goes to the nucleus and changes what the nuclear genome does.

The molecular target was identified in 2024. Casein kinase 2 is a direct and functional target of MOTS-c: the peptide binds CK2 and activates it in cell-free systems, and administration to mice prevented skeletal muscle atrophy and enhanced muscle glucose uptake, both blunted when CK2 activity was suppressed. The effects are tissue-specific — systemically administered MOTS-c binds CK2 in both fat and muscle, but stimulates it in muscle while suppressing it in fat, by differentially modifying CK2-interacting proteins ¹³.

And a human variant tests the mechanism. A naturally occurring MOTS-c variant, K14Q, has reduced CK2 binding and does not activate it or produce the peptide’s effects. Male K14Q carriers showed a higher risk of sarcopenia and type 2 diabetes in an age- and physical-activity-dependent manner; female carriers showed an age-specific reduced risk of type 2 diabetes ¹³.

That is a mechanistic case built and then stress-tested — and it is where the evidence stops. Every administration study is in mice or cells. The human data consists of circulating-concentration measurements in observational cohorts ^5,11 and one exercise physiology study whose result cuts against a common assumption about where circulating MOTS-c comes from ¹⁸.

02 · Evidence at a glance

Evidence grade

Preclinical — no interventional human trial is indexed

Structure

16 amino acids, encoded by a short open reading frame within the mitochondrial 12S rRNA gene ¹

Genome of origin

Mitochondrial, not nuclear ¹

Direct molecular target

Casein kinase 2 — binds and activates it in cell-free systems ¹³

Tissue specificity

Activates CK2 in muscle, suppresses it in fat, via differential modification of CK2-interacting proteins ¹³

Principal cascade

Folate cycle inhibition → AMPK activation ¹; CK2–PTEN–mTORC2–AKT–FOXO1 → reduced myostatin ⁵

Nuclear action

Translocates to the nucleus under metabolic stress; interacts with NRF2 and regulates antioxidant response element genes ³

Human genetic evidence

K14Q variant loses CK2 binding; carriers show sex- and activity-dependent disease risk ¹³

Human observational data

Plasma MOTS-c inversely correlated with myostatin ⁵; levels measured in neurodegenerative disease and stroke cohorts ¹¹

Human administration studies

None

Human subjects given MOTS-c

0

Indexed records

~170

Approval status

None, any jurisdiction

03 · Mechanism of action

Origin: a peptide written in the mitochondrial genome

The mitochondrial genome encodes 13 proteins of the oxidative phosphorylation machinery, two ribosomal RNAs and 22 transfer RNAs — that was the textbook account until short open reading frames embedded within the rRNA genes were found to encode signalling peptides. Humanin, from the 16S rRNA gene, was the first. MOTS-c, from the 12S rRNA gene, was identified by searching for others on the reasoning that humanin was unlikely to be alone ¹.

This origin is the compound’s most interesting structural fact and the source of its framing as a signal from the mitochondrion to the rest of the cell.

Folate cycle inhibition and AMPK

The original mechanistic account is metabolic rather than receptor-based. MOTS-c inhibits the folate cycle and the de novo purine biosynthesis tethered to it; the resulting shift in the cell’s purine intermediate pool activates AMP-activated protein kinase ¹. AMPK is the cell’s energy sensor, and activating it shifts metabolism toward catabolism and glucose uptake.

Because the effect runs through a metabolic pathway rather than a receptor, dose-response does not follow receptor occupancy, and the compound’s actions are strongest where the folate cycle carries the most flux.

CK2: the direct binding partner

For nine years the field had a pathway with nothing at the top of it. In 2024 that changed. CK2 was shown to be a direct and functional target — MOTS-c binds it and activates it in a cell-free system, which rules out the possibility that the interaction is indirect ¹³.

The tissue specificity is the striking part. Systemically administered MOTS-c binds CK2 in both fat and skeletal muscle, but activates it in muscle and suppresses it in fat, and the difference comes from which CK2-interacting proteins the peptide modifies in each tissue ¹³. A single molecule producing opposite effects on the same kinase in two tissues is not a common finding, and it is the kind of result that either explains a compound or eventually complicates it.

Downstream, CK2 activation inhibits PTEN, which increases mTORC2 activity and AKT phosphorylation, which inhibits FOXO1 — the transcription factor upstream of myostatin and other muscle-wasting genes ⁵. The chain is: MOTS-c → CK2 → PTEN inhibition → mTORC2 → AKT phosphorylation → FOXO1 inhibition → reduced myostatin ⁵.

Nuclear translocation

Under metabolic stress — glucose restriction in the reported experiments — MOTS-c moves into the nucleus in an AMPK-dependent manner and regulates a broad range of nuclear genes, including those carrying antioxidant response elements, through interaction with stress-responsive transcription factors including NRF2 ³. A separate 2025 paper identified MYH9-dependent nuclear translocation driving transcriptional activation of antioxidant genes in lung ischaemia-reperfusion ¹⁵.

A mitochondrially encoded peptide entering the nucleus and altering nuclear transcription is the single most cited reason this compound is discussed at all, and the finding has now been reproduced in a second injury model by a different group ^3,15.

Mitochondrial bioenergetics

The most recent mechanistic work used two transgenic mouse strains to show that MOTS-c administration improves skeletal muscle mitochondrial bioenergetic performance in a manner dependent on both PGC-1α and AMPK — and, importantly, without an apparent change in mitochondrial respiratory protein content. The improvement is intrinsic to existing mitochondria rather than a matter of making more of them. The same work found reduced mitochondrial reactive oxygen species emission and reduced ROS-related protein damage ¹⁸.

04 · Key research findings

Metabolic disease in rodents. The founding study reported that MOTS-c treatment in mice prevented age-dependent and high-fat-diet-induced insulin resistance, and prevented diet-induced obesity ¹. In a mouse model of gestational diabetes established by short-term high-fat diet plus low-dose streptozotocin, daily administration during pregnancy relieved hyperglycaemia and insulin resistance ⁶. Reviews have since organised the diabetes literature around risk factors, cardiac complications and potential treatment ¹⁷, and around the peptide’s relationship to exercise and mitohormesis ⁷.

Consistent direction across models, all rodent, all administration studies.

Muscle. MOTS-c prevented palmitic-acid-induced atrophy in differentiated C2C12 myotubes, and administration decreased plasma myostatin in diet-induced obese mice, through the CK2–PTEN–mTORC2–AKT–FOXO1 pathway ⁵. Administration to mice prevented skeletal muscle atrophy and enhanced muscle glucose uptake, effects blunted by suppressing CK2 ¹³. Mitochondrial bioenergetic efficiency improved through PGC-1α and AMPK ¹⁸.

The muscle story is the best-supported one and the reason this compound sits alongside the growth factors in commercial use. Every result in it is from a mouse or a myotube.

The human genetic experiment. The K14Q variant is the closest thing this compound has to a human trial, and it runs backwards: instead of giving people the peptide, it observes people whose peptide does not work. K14Q has reduced CK2 binding and does not activate it or elicit MOTS-c’s effects. Male carriers showed higher risk of sarcopenia and type 2 diabetes, dependent on age and physical activity; female carriers showed an age-specific reduced risk of type 2 diabetes ¹³.

A loss-of-function variant tracking with the diseases the peptide is proposed to prevent is meaningful support for the biology. It is not evidence that administering the peptide to someone with a functioning copy does anything.

Circulating concentrations in people. Plasma MOTS-c levels are inversely correlated with myostatin levels in human subjects ⁵. Plasma MOTS-c was measured by ELISA alongside adropin, NSE and NF-L in cohorts with neurodegenerative disease and ischaemic stroke ¹¹.

Correlational, cross-sectional, and unable to separate cause from consequence. A peptide released under metabolic stress will correlate with markers of metabolic stress whichever way the causal arrow points.

A human physiology result that complicates the exercise narrative. MOTS-c is widely described as an exercise-responsive peptide. In a human study using one-legged knee extensor exercise, interstitial MOTS-c levels rose but no change was observed in the arterio-venous difference across the working limb — which suggests that skeletal muscle may not be the source of circulating MOTS-c in response to exercise ¹⁸.

This is the only indexed human physiology experiment on the peptide, and its finding runs against the assumption most of the field has been working with.

Organ protection and injury models. MOTS-c attenuated lung ischaemia-reperfusion injury in rats, with endothelial cells showing the largest upregulation and exogenous administration reducing oxidative damage ¹⁵. It attenuated mitochondrial dysfunction, pyroptosis and cartilage degradation in a murine osteoarthritis model via an Nrf2-dependent mechanism ¹⁶. It ameliorated lysosomal membrane permeability and improved survival of soft tissue transplantation in ischaemic flaps, inhibiting PLA2G4A through MAPK1-MAPK3-NFKB signalling ¹⁹. In dystrophic mice, MOTS-c promoted uptake and efficacy of a phosphorodiamidate morpholino oligomer, with the protocol used in that study giving 500 µg MOTS-c alongside 12.5 mg/kg/week of the oligomer for three weeks followed by 12.5 mg/kg/month for three months, and reporting up to a 25-fold increase in diaphragm dystrophin ⁴.

Four independent injury models, four independent groups, a consistent direction. This is genuine breadth. It is also entirely rodent, and organ-protection findings in acute injury models translate to humans at a low rate across all of medicine.

Oncology. MOTS-c suppressed ovarian cancer progression by attenuating USP7-mediated LARS1 deubiquitination; the paper notes that clinical studies had suggested a possible link between MOTS-c and human cancer, and that its role in tumorigenesis had not previously been investigated ¹⁴.

A single study, in one tumour type, reporting suppression. It does not resolve the general question of what a proliferative-signalling-adjacent peptide does to existing neoplasia, and no other study has asked it.

05 · Evidence overview

06 · Safety profile

Animal data. No formal toxicology programme exists. The administration studies in mice and rats report efficacy endpoints over days to months and do not systematically record adverse events ^{1,4,5,6,13,15,16,18,19}. The dystrophic mouse study is the longest exposure described — repeated administration over roughly three months — and reported therapeutic rather than toxic effects ⁴. Nothing in the indexed record describes a dose-limiting toxicity in any species, which reflects absence of investigation rather than absence of risk.

Human data. No human has been given MOTS-c in any indexed study. The human record consists of measurements of endogenous concentrations ^5,11, a genetic association ¹³, and one exercise physiology experiment ¹⁸. None of these involves administration, so none of them carries safety information about administration.

What is genuinely unknown. Pharmacokinetics in any species, absent from the indexed record — a 16-residue unmodified peptide would be expected to clear rapidly, and no study reports a concentration-time curve. The consequences of the tissue-divergent CK2 effect: activating a kinase in muscle while suppressing it in fat ¹³ means a systemic dose does opposite things in two tissues, and what that does to a third tissue has not been examined. CK2 itself is a pleiotropic kinase with hundreds of substrates and established roles in cell survival and proliferation, and chronic modulation of it has not been studied. Whether sustained AMPK activation and NRF2 engagement ^1,3 carry the risks associated with chronic activation of those pathways, including effects on cells that have already transformed — NRF2 activation is protective in normal tissue and is a known survival mechanism in some tumours, and no study has addressed this for MOTS-c. Repeat-dose toxicology, genotoxicity, reproductive toxicology and carcinogenicity: none performed. Immunogenicity, unassessed. And the identity, purity and stereochemistry of any material sold under this name: no published analysis has examined a commercial preparation.

07 · US regulatory status

Current as of 6 September 2026. MOTS-c is not approved as a drug in the United States or any other jurisdiction and is not a controlled substance.

No marketing authorisation has been sought or granted anywhere. No investigational new drug programme for MOTS-c appears in the peer-reviewed record. Reviews published between 2022 and 2025 consistently describe the compound as promising and note that it has been used infrequently in disease treatment ¹⁰, and that phase-appropriate clinical evaluation has not begun ^9,12,17.

A 2026 review of peptides marketed directly to patients includes MOTS-c among compounds where demand has outrun the evidence, making the general finding for that class: favourable outcomes in animal models, scarce rigorous human safety data, and potential for serious harm ²⁰.

Under the World Anti-Doping Code, peptide hormones and growth factors are prohibited at all times. Competitors should consult the current Prohibited List directly rather than rely on secondary summaries, including this one.

08 · Limitations of the evidence

1. No one has been given this peptide in a study. The human record is measurement and genetics, not administration ^5,11,13,18. Every claim about what MOTS-c does when administered comes from mice.
2. The strength of the mechanism is not evidence of clinical effect, and the two are routinely conflated for this compound. An identified direct target ¹³, a mapped cascade ⁵, a nuclear action ³ and a loss-of-function human variant ¹³ together make a persuasive biological case. They say nothing about whether injecting the peptide into a person with normal MOTS-c function produces a benefit.
3. The genetic evidence is sex-divergent in a way the field has not explained. Male K14Q carriers showed increased risk of sarcopenia and type 2 diabetes; female carriers showed an age-specific reduced risk of type 2 diabetes ¹³. A variant that is harmful in one sex and apparently protective in the other is a signal that the biology is not yet fully understood.
4. The exercise premise is challenged by the only human physiology study. Interstitial MOTS-c rose during one-legged knee extensor exercise while the arterio-venous difference did not change, suggesting skeletal muscle may not be the source of circulating MOTS-c during exercise ¹⁸. Much of the popular framing of this compound assumes the opposite.
5. Correlational human data cannot establish direction. Plasma MOTS-c inversely correlating with myostatin ⁵, or differing across neurological cohorts ¹¹, is compatible with MOTS-c causing the difference, with the difference causing MOTS-c release, and with both responding to a third factor.
6. Animal-to-human translation faces the usual barrier and one specific one. The rodent models are acute or diet-induced disease states, and the tissue-specific CK2 effect ¹³ means the balance of muscle and adipose responses in a mouse on a high-fat diet may not be the balance in a person.
7. Organ-protection results in acute injury models have a poor translation record generally. Lung ischaemia-reperfusion ¹⁵, osteoarthritis ¹⁶ and flap survival ¹⁹ are all findings of that type, from three different groups. Their consistency is real; their predictive value for human outcomes is low across the whole field.
8. Pharmacokinetics are entirely absent. A short unmodified peptide administered systemically raises immediate questions about half-life and route, and no indexed study answers them for any species.
9. Publication bias is plausible and unmeasurable. The literature has grown from four records in 2015 to more than thirty per year, and is overwhelmingly positive. Fields that expand this fast around a single attractive concept accumulate unpublished nulls, and nothing here permits a correction.
10. Nothing is known about commercial material. No published analysis has examined the identity, purity or content of any product sold as MOTS-c.

09 · References

1. Lee C, Zeng J, Drew BG, et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab. 2015 Mar 3;21(3):443–454.

   PMID 25738459 ↗

2. Lee C, Kim KH, Cohen P. MOTS-c: a novel mitochondrial-derived peptide regulating muscle and fat metabolism. Free Radic Biol Med. 2016 Nov;100:182–187.

   PMID 27216708 ↗

3. Kim KH, Son JM, Benayoun BA, Lee C. The mitochondrial-encoded peptide MOTS-c translocates to the nucleus to regulate nuclear gene expression in response to metabolic stress. Cell Metab. 2018 Sep 4;28(3):516–524.e7.

   PMID 29983246 ↗

4. Ran N, Lin C, Leng L, et al. MOTS-c promotes phosphorodiamidate morpholino oligomer uptake and efficacy in dystrophic mice. EMBO Mol Med. 2021 Feb 5;13(2):e12993.

   PMID 33337582 ↗

5. Kumagai H, Coelho AR, Wan J, et al. MOTS-c reduces myostatin and muscle atrophy signaling. Am J Physiol Endocrinol Metab. 2021 Apr 1;320(4):E680–E690.

   PMID 33554779 ↗

6. Yin Y, Pan Y, He J, et al. The mitochondrial-derived peptide MOTS-c relieves hyperglycemia and insulin resistance in gestational diabetes mellitus. Pharmacol Res. 2022 Jan;175:105987.

   PMID 34798268 ↗

7. Yoon TK, Lee CH, Kwon O, Kim MS. Exercise, mitohormesis, and mitochondrial ORF of the 12S rRNA type-c (MOTS-c). Diabetes Metab J. 2022 May;46(3):402–413.

   PMID 35656563 ↗

8. Mohtashami Z, Singh MK, Salimiaghdam N, Ozgul M, Kenney MC. MOTS-c, the most recent mitochondrial derived peptide in human aging and age-related diseases. Int J Mol Sci. 2022 Oct 9;23(19):11991.

   PMID 36233287 ↗

9. Wan W, Zhang L, Lin Y, et al. Mitochondria-derived peptide MOTS-c: effects and mechanisms related to stress, metabolism and aging. J Transl Med. 2023 Jan 20;21(1):36.

   PMID 36670507 ↗

10. Zheng Y, Wei Z, Wang T. MOTS-c: a promising mitochondrial-derived peptide for therapeutic exploitation. Front Endocrinol (Lausanne). 2023 Jan 25;14:1120533.

    PMID 36761202 ↗

11. Saçmacı H, Çakır M, Özcan SS. Adropin and MOTS-c as new peptides: do levels change in neurodegenerative diseases and ischemic stroke? J Biochem Mol Toxicol. 2023 Feb;37(2):e23246.

    PMID 36303331 ↗

12. Kong BS, Lee C, Cho YM. Mitochondrial-encoded peptide MOTS-c, diabetes, and aging-related diseases. Diabetes Metab J. 2023 May;47(3):315–324.

    PMID 36824008 ↗

13. Kumagai H, Kim SJ, Miller B, et al. MOTS-c modulates skeletal muscle function by directly binding and activating CK2. iScience. 2024 Oct 19;27(11):111212.

    PMID 39559755 ↗

14. Yin Y, Li Y, Ma B, et al. Mitochondrial-derived peptide MOTS-c suppresses ovarian cancer progression by attenuating USP7-mediated LARS1 deubiquitination. Adv Sci (Weinh). 2024 Nov;11(43):e2405620.

    PMID 39321430 ↗

15. Li X, Zhan F, Qiu G, et al. MOTS-c attenuates lung ischemia-reperfusion injury via MYH9-dependent nuclear translocation and transcriptional activation of antioxidant genes. Redox Biol. 2025 Jul;84:103681.

    PMID 40403491 ↗

16. Li K, Yang T, Chen F, et al. MOTS-c attenuates mitochondrial dysfunction induces pyroptosis and cartilage degradation in osteoarthritis via an Nrf2-dependent mechanism. Free Radic Biol Med. 2025 Dec 16;241:717–731.

    PMID 41043625 ↗

17. Fang T, Han JC, Taberner A, Pham T. MOTS-c in type 2 diabetes mellitus: from risk factors to cardiac complications and potential treatment. Life Sci. 2025 Dec 1;382:124009.

    PMID 41083123 ↗

18. Gudiksen A, Hansen CC, van der Stede T, et al. MOTS-c improves intrinsic muscle mitochondrial bioenergetic health and efficiency in a PGC-1alpha/AMPK-dependent manner. Free Radic Biol Med. 2026 Mar 16;246:682–696.

    PMID 41520850 ↗

19. Shi J, Wu Y, Liu X, et al. MOTS-c, a mitochondrial-derived peptide, ameliorates lysosomal membrane permeability and improves survival of soft tissue transplantation. Autophagy. 2026 Jun 2:1–30.

    PMID 42153537 ↗

20. Mendias CL, Awan TM. Safety and efficacy of approved and unapproved peptide therapies for musculoskeletal injuries and athletic performance. Sports Med. 2026 Aug;56(8):1921–1935.

    PMID 41966639 ↗