MOTS-c

What Is MOTS-c?

MOTS-c is a 16-amino-acid peptide encoded within the mitochondrial genome rather than the nuclear genome. Its name stands for mitochondrial open reading frame of the 12S rRNA type-c, reflecting its origin in a short open reading frame inside the mitochondrial 12S ribosomal RNA gene^[1].

MOTS-c belongs to a small family called mitochondrial-derived peptides (MDPs). Humanin was the first member described, and the discovery of MOTS-c added to evidence that mitochondrial DNA encodes more than its 37 canonical genes^[2]. Other reported MDPs include the 16S rRNA-encoded small humanin-like peptides (SHLP1-6) and SHMOOSE^[3].

In the original report, the primary target organ of MOTS-c appeared to be skeletal muscle^[1]. Reviews note that the peptide is detected in multiple tissues and in plasma, and that circulating levels decline with age in the studies summarized^[4]. Most of the published work is preclinical, using cultured cells and rodent models.

Chemical Structure and Molecular Identity

MOTS-c is a linear, unmodified 16-residue peptide with the sequence MRWQEMGYIFYPRKLR and the molecular formula C101H152N28O22S2. PubChem lists a molecular weight of 2174.6 g/mol under CID 146675088 and CAS number 1627580-64-6.

The PubChem record describes the peptide with a free N-terminal amine and a free C-terminal carboxylic acid (H-MRWQEMGYIFYPRKLR-OH). The two sulfur atoms in the formula come from its two methionine residues, at positions 1 and 6. The sequence carries three arginines and one lysine against a single glutamate, so the peptide is strongly basic overall.

• Length: 16 amino acids, all standard L-residues
• Aromatic residues: one tryptophan, one phenylalanine, two tyrosines
• Charged residues: Arg2, Glu5, Arg13, Lys14, Arg16

A naturally occurring human variant, K14Q MOTS-c, replaces the lysine at position 14 with glutamine. In biochemical work this variant showed reduced binding to the kinase CK2 and did not activate it^[5], which makes position 14 one of the few residues with a reported functional role.

Research History and Development

MOTS-c was first described in 2015 by Lee and colleagues, and research has since moved from metabolic physiology into aging, muscle, and disease models. The 2015 paper in Cell Metabolism identified the open reading frame in mitochondrial 12S rRNA and reported effects on insulin sensitivity and obesity in mice^[1].

A 2016 review from the same group framed MOTS-c and humanin as examples of mitochondrial-encoded signals that act at the cellular and organismal level, sometimes called mitochondrial hormones^[2]. In 2018, the group reported that MOTS-c moves into the nucleus under metabolic stress and regulates nuclear gene expression^[6]. A 2021 study in Nature Communications linked MOTS-c to exercise and age-related physical decline in mice, with supporting human exercise data^[7].

From 2022 onward, studies extended MOTS-c into gestational diabetes^[8], hepatitis B virus infection^[9], ovarian cancer^[10], lung ischemia-reperfusion injury^[11], and muscle mitochondrial bioenergetics^[12]. A 2024 study identified the kinase CK2 as a direct binding target^[5]. No development code or approved clinical product has emerged; a 2023 review noted that no effective method of applying MOTS-c in the clinic had been developed^[4].

Mechanisms Studied in Research

The best-characterized mechanism is inhibition of the folate cycle, which leads to activation of AMPK, the cell’s main energy-sensing kinase. In the 2015 report, MOTS-c inhibited the folate cycle and its tethered de novo purine biosynthesis, resulting in AMPK activation^[1]. Later reviews describe this as the folate-AICAR-AMPK pathway, in which accumulation of the purine intermediate AICAR drives AMPK signaling^[13][14].

Nuclear translocation and gene regulation

Under metabolic stress such as glucose restriction, MOTS-c translocated to the nucleus in an AMPK-dependent manner, regulated genes containing antioxidant response elements, and interacted with the stress-responsive transcription factor NRF2^[6]. In rat lung ischemia-reperfusion models, nuclear entry in endothelial cells depended on the motor protein MYH9, whose phosphorylation by CK2 enabled MOTS-c transport; sequencing showed MOTS-c at promoters of antioxidant genes such as HMOX1 and NQO1^[11].

Other reported targets

Reviews also report that MOTS-c expression rises in response to stress and exercise^[13], which has led some authors to discuss it as a candidate exercise mimetic^[15].

Key Findings From Published Studies

Published findings are dominated by mouse and cell studies showing metabolic and muscle effects, with human data limited to observational biomarker, genetic, and exercise measurements. No controlled trial of administered MOTS-c in humans appears in the literature summarized here.

Metabolism and insulin sensitivity (animal)

In mice, MOTS-c treatment prevented age-dependent and high-fat-diet-induced insulin resistance as well as diet-induced obesity^[1]. In a gestational diabetes mouse model induced by a short-term high-fat diet plus streptozotocin, MOTS-c given during pregnancy alleviated hyperglycemia, improved insulin sensitivity and glucose tolerance, reduced diabetes-related birth weight increases and offspring deaths, and protected pancreatic beta cells; it also raised glucose uptake in vitro^[8].

Muscle and physical capacity

MOTS-c enhanced physical performance in young (2-month), middle-aged (12-month), and old (22-month) mice, and treatment initiated late in life (23.5 months) increased physical capacity and healthspan^[7]. In mice, MOTS-c prevented skeletal muscle atrophy and enhanced muscle glucose uptake, effects that were blunted when CK2 activity was suppressed^[5].

In humans, exercise induced endogenous MOTS-c expression in skeletal muscle and in circulation^[7]. A 2026 study found that interstitial MOTS-c rose during one-legged knee-extensor exercise but with no arterio-venous difference, suggesting skeletal muscle may not be the source of circulating MOTS-c^[12]. In genetic association data, male carriers of the K14Q variant showed a higher risk of sarcopenia and type 2 diabetes in an age- and activity-dependent manner, while female carriers showed an age-specific reduced type 2 diabetes risk^[5].

Other disease models

• Hepatitis B: in a cohort of 85 healthy subjects and 404 patients with HBV infection, MOTS-c levels correlated negatively with HBV DNA (R = −0.71); in mice and cells, MOTS-c inhibited HBV replication by 50–70% without notable toxicity^[9].
• Ovarian cancer: MOTS-c levels were lower in serum and tumor tissue from patients and associated with poor prognosis; exogenous MOTS-c inhibited proliferation, migration, and invasion of ovarian cancer cells and showed anti-tumor effects in vivo without systemic toxicity^[10].
• Lung injury: in rats, exogenous MOTS-c reduced oxidative damage, inflammation, and mortality after lung ischemia-reperfusion; in patients, the rise in serum MOTS-c within 24 hours after cardiopulmonary bypass predicted ARDS, with a combined model reaching an AUC of 0.885^[11].
• Bone: a review reports that MOTS-c promotes osteoblast proliferation, differentiation, and mineralization and inhibits osteoclast formation in experimental studies^[16].

Nearly all of the interventional findings above come from exogenous synthetic MOTS-c rather than measurements of the endogenous peptide.

Because most MOTS-c findings rely on synthetic peptide, researchers typically confirm sequence identity and purity with HPLC and mass-spectrometry certificates of analysis.

Because most MOTS-c findings rely on synthetic peptide, researchers typically confirm sequence identity and purity with HPLC and mass-spectrometry certificates of analysis.

Regulatory and Research Status

MOTS-c is not an FDA-approved drug and remains an investigational research compound. A 2026 narrative review in Sports Medicine listed MOTS-c among unapproved peptides marketed directly to patients outside regulatory oversight, and noted that rigorous human safety data for such peptides are scarce^[17].

The evidence base consists of in-vitro experiments, rodent studies, human observational measurements, and narrative reviews. Reviews published in 2023 describe its potential relevance to diabetes, obesity, aging, cardiovascular disease, and inflammation while noting that clinical application has not been established^[4][3]. The same Sports Medicine review cautions that favorable outcomes in animal models do not establish safety or efficacy in people^[17].

For researchers, the open questions include the source of circulating MOTS-c, how tissue-specific signaling through CK2 is controlled, and whether observational associations in human cohorts reflect a causal role.