MOTS-c

What MOTS-c is

MOTS-c — short for Mitochondrial Open Reading Frame of the 12S rRNA-c — is a 16-amino-acid peptide belonging to the mitochondrial-derived peptide (MDP) family, which also includes humanin and the small humanin-like peptides (SHLPs 1–6) ^[1]. It was identified in 2015 by Changhan David Lee, Kim, Cohen, and colleagues at the University of Southern California through an in silico search for short open reading frames (sORFs) encoding bioactive peptides within the 12S ribosomal RNA gene of mitochondrial DNA [2, 3]. Unlike virtually all other known signaling peptides — which are encoded in the nuclear genome — MOTS-c is encoded within the mitochondrial genome itself, a discovery that established a fundamentally new class of intercellular signaling molecules [1, 4].

The peptide's mitochondrial origin was confirmed by showing that cells selectively depleted of mitochondrial DNA (ρ0 cells) lost both the 12S rRNA transcript and all detectable MOTS-c expression, ruling out nuclear DNA as the source ^[3]. Although the encoding gene resides in mitochondria, the transcript is exported and translated in the cytoplasm; the resulting peptide can then translocate to the nucleus, where it modulates gene expression in response to metabolic stress [2, 5]. The amino-acid sequence of MOTS-c is highly conserved across 14 species including humans and mice, pointing to an evolutionarily important biological role ^[2].

What it is being researched for

1. Metabolic homeostasis and insulin sensitivity

The landmark 2015 Cell Metabolism paper by Lee et al. identified MOTS-c as a regulator of metabolic homeostasis whose primary target organ appears to be skeletal muscle ^[6]. In high-fat-diet mouse models, MOTS-c prevented diet-induced obesity and improved insulin sensitivity, in part by promoting GLUT4-mediated glucose uptake and suppressing circulating pro-inflammatory cytokines IL-6 and TNFα ^[6]. Metabolomics studies in obese mice subsequently found that MOTS-c reduced metabolites in the sphingolipid, monoacylglycerol, and dicarboxylate pathways — all of which are upregulated in obesity and type-2-diabetes models — suggesting a broad influence on lipid and glucose metabolism ^[7]. A 2018 human observational study measured plasma MOTS-c in lean and obese adults and found that circulating levels correlated significantly with insulin-sensitivity markers in lean, but not obese, individuals, indicating that the relationship between MOTS-c and insulin regulation may depend on the prevailing metabolic state ^[8].

2. Exercise physiology and physical performance

Human research has confirmed that acute exercise raises MOTS-c levels in both skeletal muscle and systemic circulation, supporting its classification as an exercise-induced mitochondrial signal ^[5]. A 2021 Nature Communications study by Reynolds et al. reported that MOTS-c significantly enhanced treadmill performance in young, middle-aged, and old mice, with older mice running approximately twice as long and twice as far as untreated controls ^[5]. Late-life treatment that began when mice were roughly equivalent to human ages above 65 trended toward increased median and maximum lifespan and was associated with compressed morbidity and improved healthspan ^[5]. Gene set enrichment analyses in treated muscle tissue identified upregulated pathways related to AMPK signaling, glycolysis, central carbon metabolism, and longevity, mechanistically linking the physical performance gains to the peptide's core metabolic functions ^[5].

3. Healthy aging and longevity

Endogenous MOTS-c levels decline with age in both plasma and skeletal muscle, a pattern that coincides with the onset of age-related insulin resistance [6, 9]. Research suggests this age-related decline may contribute to reduced metabolic flexibility and physical capacity in older organisms, while restoration of MOTS-c levels can partially reverse these phenotypes in aged mice ^[9]. A 2023 Springer review noted that MOTS-c has been found to affect obesity, inflammation, neuroprotection, and aging-induced hypokinesia, positioning it as a candidate contributor to healthy aging programmes ^[9]. A 2019 Physiological Reports study further proposed that MOTS-c levels could serve as biomarkers of metabolic dysfunction, as the peptide's circulating concentrations reflect the overall metabolic condition of the organism ^[7].

4. Cardiovascular protection

Preclinical research has extended MOTS-c's biological profile to the heart. A 2022 PubMed-indexed study (PMID 36156853) showed that MOTS-c attenuated cardiac dysfunction and pathological remodelling in a mouse model of pressure-overload-induced heart failure, while simultaneously reducing inflammatory cytokines and upregulating antioxidant capacity via AMPK pathway activation ^[10]. Separate work in a septic cardiomyopathy model found that MOTS-c reduced inflammatory cytokine mRNA expression (IL-1β, IL-4, IL-6, TNFα) and circulating markers of myocardial injury, and attenuated cardiomyocyte mitochondrial dysfunction and apoptosis through AMPK, AKT, and ERK signalling ^[10]. These findings are entirely preclinical, and no cardiovascular outcomes in humans have been evaluated in controlled trials.

5. Inflammation and pain modulation

Multiple rodent studies have identified anti-inflammatory effects of MOTS-c across different pain models. In models of inflammatory pain, MOTS-c produced anti-allodynic effects in formalin-induced acute pain, capsaicin-evoked nocifensive behaviour, and carrageenan/CFA-induced chronic pain, with the peptide reducing the release of inflammatory mediators and suppressing activation of nociceptive neurons ^[11]. A separate PubMed-indexed study (PMID 37285113) found that MOTS-c inhibited microglial activation and neuronal oxidative damage in the spinal cord in a neuropathic pain model, working through AMPK pathway activation ^[11]. Bone-focused research demonstrated that MOTS-c alleviated inflammation-driven bone erosion in a particle-induced osteolysis mouse model by modulating osteocyte-osteoclast crosstalk ^[12]. All findings remain in animal models, and no human pain or inflammation trials have been published.

6. Bone metabolism

Research in rodent models has linked MOTS-c to bone-preserving effects. Studies cited in PMC reviews noted that MOTS-c prevents ovariectomy-induced osteoporosis in mice and promotes the differentiation of bone mesenchymal stem cells into osteoblasts in rat models, both via the AMPK pathway ^[13]. A 2024 paper published in Acta Biochimica et Biophysica Sinica reported that endogenous MOTS-c plasma levels were significantly lower in a bone cancer pain model, and that restoring MOTS-c attenuated bone destruction by modulating osteoclast and immune cell function in the tumour microenvironment ^[12]. Brown adipose tissue has also been identified as a potential MOTS-c target, where the peptide appears to influence mitochondrial number and function and may help prevent ovariectomy-induced obesity and insulin resistance through the AMPK pathway ^[13].

7. Neuroprotection and cognitive biology

Early laboratory work suggests that MOTS-c and cell-penetrating analogues of it can suppress neuroinflammation and reduce markers of microglia and astrocyte activation in brain tissue challenged with LPS or amyloid-β ^[11]. A study in a traumatic brain injury mouse model found that MOTS-c mitigated the inflammatory response, decreased molecular damage, and reduced cell death by downregulating macrophage migration inhibitory factor expression and activating the retrograde endocannabinoid signalling pathway ^[11]. However, a review by the Alzheimer's Drug Discovery Foundation noted that the native peptide does not readily cross the blood-brain barrier, and as of that review there were no human studies demonstrating cognitive benefit or protection against dementia ^[14]. This remains one of the most preliminary and unresolved areas of MOTS-c research.

How it is thought to work

MOTS-c exerts its primary effects by disrupting the folate-methionine cycle inside cells, specifically by consuming 5-methyl-tetrahydrofolate (5Me-THF) under conditions of metabolic stress [4, 15]. This interruption reduces flux through the folate and de novo purine synthesis pathways, causing an intracellular accumulation of AICAR (5-aminoimidazole-4-carboxamide ribonucleoside), a naturally occurring nucleotide intermediate [6, 15]. AICAR is a well-established activator of AMP-activated protein kinase (AMPK), a central energy sensor in cells, and MOTS-c thereby switches on AMPK signalling independently of classical changes in the AMP-to-ATP ratio ^[6]. In skeletal muscle, downstream AMPK activation triggers GLUT4 glucose transporter translocation to the cell surface, increasing cellular glucose uptake, and also upregulates genes involved in fatty-acid oxidation and mitochondrial biogenesis [6, 15].

Beyond this folate-AICAR-AMPK axis, MOTS-c undergoes nuclear translocation during metabolic stress, where it binds to antioxidant response elements (AREs) and regulates the expression of stress-resistance and metabolism-related genes, including GLUT4, STAT3, and IL-10 [4, 15]. This nucleus-directed activity means MOTS-c functions as both an endocrine-like signal (communicating metabolic state to distant tissues via circulation) and as a direct transcriptional co-regulator [1, 5]. MOTS-c also increases intracellular NAD⁺ levels, and evidence suggests the deacetylase SIRT1 is partially involved in translating these signals into downstream physiological effects ^[13]. The convergence of AMPK activation, ARE-mediated gene regulation, and SIRT1 engagement allows MOTS-c to coordinate glucose homeostasis, lipid metabolism, inflammation, and cellular stress resistance through a single mitochondria-to-nucleus retrograde signalling pathway.

Where the evidence stands

The preponderance of published MOTS-c evidence comes from cell culture and rodent experiments. The foundational 2015 Cell Metabolism study established that MOTS-c prevents high-fat-diet-induced insulin resistance and obesity in mice, and the 2021 Nature Communications study confirmed exercise-induced expression in humans and significant physical performance gains in mice of all age groups [5, 6]. Metabolomics analyses in diet-induced obese mice identified specific lipid and metabolite pathway changes downstream of MOTS-c treatment, deepening mechanistic understanding ^[7]. Across cardiovascular, bone, neurological, and pain models, multiple independent rodent studies have consistently reported AMPK-dependent protective effects, suggesting a robust and reproducible preclinical signal [10, 11, 12]. However, these findings do not establish human efficacy or safety.

Human data are limited and largely observational. The 2018 study by Cataldo et al. measured circulating MOTS-c in lean versus obese adults without administering exogenous peptide, finding only correlative associations between endogenous levels and insulin sensitivity markers ^[8]. A Phase 1a/1b clinical trial tested CB4211 — a MOTS-c analogue, not native MOTS-c — in healthy volunteers and a subset with fatty liver disease (NCT03998514), reporting short-term tolerability alongside trends toward reduced liver enzymes and glucose, but the study enrolled too few participants over too short a period to draw therapeutic conclusions ^[14]. As of mid-2026, no completed randomised controlled trial of native MOTS-c in humans has been published; a Phase 2a native-peptide trial (MOTS-MET) targeting insulin sensitivity in older adults was listed as enrolling with no efficacy results posted ^[14]. Key gaps include the absence of validated human pharmacokinetics, an undefined long-term safety profile, and uncertainty about whether the pharmacological effects observed in mouse models translate to humans at any exposure level [14, 15].

Frequently asked questions

What is MOTS-c and where does it come from?

MOTS-c is a 16-amino-acid peptide encoded within the 12S ribosomal RNA gene of mitochondrial DNA — making it one of the only known signaling peptides to originate from the mitochondrial genome rather than the nuclear genome. It was discovered in 2015 by researchers at the University of Southern California. In the body, it is produced primarily in skeletal muscle and circulates in blood plasma, and its levels rise naturally during exercise.

What is MOTS-c studied for?

Research has investigated MOTS-c in the areas of metabolic homeostasis, insulin sensitivity, obesity, exercise performance, healthy aging, cardiovascular protection, bone metabolism, neuroinflammation, and pain modulation. The vast majority of this research has been conducted in cell culture and animal models. No human therapeutic use has been approved by any regulatory authority.

How does MOTS-c work at the cellular level?

MOTS-c disrupts the folate-methionine cycle inside cells, causing an accumulation of a molecule called AICAR, which then activates the energy-sensing enzyme AMPK. AMPK activation promotes glucose uptake, fatty-acid oxidation, and mitochondrial biogenesis. MOTS-c can also move to the cell nucleus during metabolic stress and directly regulate gene expression through antioxidant response elements.

Does MOTS-c decline with age?

Yes. Animal and human observational studies have documented that circulating and muscle MOTS-c levels decrease with age, a pattern that coincides with the onset of age-related insulin resistance and reduced physical capacity. Whether supplementing declining levels with exogenous peptide produces equivalent physiological benefits in humans has not been confirmed in controlled clinical trials.

Is MOTS-c the same as an exercise mimetic?

Researchers have described MOTS-c as an 'exercise mimetic' because it activates several of the same cellular pathways — particularly AMPK — that are switched on during physical activity. Human studies have confirmed that endogenous MOTS-c levels rise in skeletal muscle and blood after exercise. Whether exogenous MOTS-c reliably reproduces the full spectrum of exercise benefits in humans has not been demonstrated in clinical trials.

Has MOTS-c been tested in human clinical trials?

Native MOTS-c has not been tested as an exogenous therapeutic in any published, completed human trial. A structurally modified analogue called CB4211 was evaluated in a Phase 1a/1b study (NCT03998514) and showed short-term tolerability, but that compound differs from the native peptide. A Phase 2a trial of native MOTS-c was registered as enrolling as of mid-2026 but had not posted results.

Is MOTS-c approved by the FDA or Health Canada?

No. MOTS-c has not been approved by the FDA, Health Canada, or any other major regulatory body as a therapeutic agent. The FDA has listed MOTS-c among bulk drug substances with potential significant safety risks for compounding purposes. It is not approved for human use and is intended solely for laboratory research.

What are the known safety risks or side effects of MOTS-c?

No peer-reviewed human safety database for native MOTS-c exists. The analogue CB4211 was generally well tolerated in its short-term Phase 1 study but was associated with persistent injection-site reactions. Human pharmacokinetics, organ toxicity thresholds, drug interaction potential, and long-term safety are all currently unknown for both native MOTS-c and its analogues.

Is MOTS-c on the WADA prohibited list?

According to publicly available regulatory commentary, MOTS-c is banned at all times under WADA's prohibited list as an AMPK activator, and no therapeutic use exemption is available. Researchers and athletes operating in drug-tested environments should be aware of this classification.

How does MOTS-c relate to other mitochondrial-derived peptides like humanin?

Humanin was the first mitochondrial-derived peptide (MDP) characterised, and its discovery alongside MOTS-c established a new class of mitochondria-to-cell signalling molecules. Both peptides are encoded in the mitochondrial genome, circulate in plasma, and decline with age, but they have distinct amino-acid sequences, target organs, and mechanistic pathways. MOTS-c's primary focus is metabolic regulation via the folate-AICAR-AMPK axis, whereas humanin has been studied more in the context of neuroprotection and apoptosis.

Glossary

Mitochondrial-derived peptide (MDP)

A class of small bioactive peptides encoded within the mitochondrial genome that are secreted and act as signaling molecules coordinating cellular and systemic physiology.

AMPK (AMP-activated protein kinase)

A master energy-sensing enzyme in cells that, when activated, promotes glucose uptake, fatty-acid oxidation, and mitochondrial biogenesis while suppressing energy-consuming anabolic processes.

AICAR (5-aminoimidazole-4-carboxamide ribonucleoside)

An endogenous intermediate of purine biosynthesis that activates AMPK and is produced in elevated amounts when MOTS-c disrupts the folate-methionine cycle.

Folate-methionine cycle

A cellular metabolic pathway that transfers one-carbon units for DNA methylation and purine synthesis; MOTS-c is thought to work primarily by inhibiting flux through this cycle.

sORF (short open reading frame)

A short DNA sequence that codes for a small peptide; MOTS-c was discovered by searching for sORFs within the mitochondrial 12S rRNA gene region.

Exercise mimetic

A compound that activates some or all of the molecular pathways triggered by physical exercise, potentially reproducing metabolic benefits in the absence of physical activity.

GLUT4 (glucose transporter type 4)

An insulin- and exercise-regulated glucose transporter that moves to the surface of skeletal muscle cells to facilitate glucose uptake; its expression and translocation are upregulated by MOTS-c in animal models.

Antioxidant response element (ARE)

A specific DNA sequence in the nucleus that, when bound by activating factors such as MOTS-c, switches on genes encoding antioxidant and stress-resistance proteins.

References

1. MOTS-c: A promising mitochondrial-derived peptide for therapeutic exploitation — PMC / Frontiers in Endocrinology (2023)
2. Mitochondrial-Encoded Peptide MOTS-c, Diabetes, and Aging-Related Diseases — Diabetes & Metabolism Journal (2021)
3. The Mitochondrial-Derived Peptide MOTS-c Promotes Metabolic Homeostasis and Reduces Obesity and Insulin Resistance — ScienceDirect (full text) — Cell Metabolism (2015)
4. MOTS-c Functionally Prevents Metabolic Disorders — Metabolites / PubMed (PMID 36677050, 2023)
5. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis — Nature Communications / PMC (2021)
6. The Mitochondrial-Derived Peptide MOTS-c Promotes Metabolic Homeostasis and Reduces Obesity and Insulin Resistance — Cell Metabolism (2015)
7. The mitochondrial-derived peptide MOTS-c is a regulator of plasma metabolites and enhances insulin sensitivity — Physiological Reports / PMC (2019)
8. Plasma MOTS-c levels are associated with insulin sensitivity in lean but not in obese individuals — Journal of Investigative Medicine / PubMed (PMID 29593067, 2018)
9. Mitochondria-derived peptide MOTS-c: effects and mechanisms related to stress, metabolism and aging — Journal of Translational Medicine / Springer (2023)
10. Mitochondrial derived peptide MOTS-c prevents the development of heart failure under pressure overload conditions in mice — Journal of Cellular and Molecular Medicine / PubMed (PMID 36156853, 2022)
11. Central and peripheral mechanism of MOTS-c attenuates pain hypersensitivity in a mice model of inflammatory pain — PubMed (PMID 37899006, 2023)
12. MOTS-c is an effective target for treating cancer-induced bone pain through the induction of AMPK-mediated mitochondrial biogenesis — Acta Biochimica et Biophysica Sinica / PMC (2024)
13. The mitochondrial-derived peptide MOTS-c is a regulator of plasma metabolites and enhances insulin sensitivity (PMC full text, includes bone and BAT data citations) — PMC review article (2019)
14. MOTS-c — Cognitive Vitality Evidence Summary (Alzheimer's Drug Discovery Foundation) — Alzheimer's Drug Discovery Foundation (Cognitive Vitality)