What does MOTS-c stand for?

Mitochondrial Open Reading Frame of the 12S rRNA type-c, which describes exactly where in the mitochondrial genome its coding sequence sits.

It is often described as one because it is released and acts at a distance, but it is more precisely a mitochondrial-derived signalling peptide. The distinction matters mainly because its origin is mitochondrial DNA rather than the nuclear genome.

Is MOTS-c approved for any use?

No. It holds no marketing authorisation anywhere and is supplied for laboratory research only.

Is MOTS-c on the WADA prohibited list?

Yes. It is prohibited in sport, which is worth knowing for anyone whose research context involves competitive athletes.

MOTS-c (Mitochondrial Peptide)

What Is MOTS-c? A Complete Research Overview

JMWritten & reviewed by Jack Muncaster · Founder, UK PeptidesLast reviewed 2026-08-234 cited sources

MOTS-c is a 16-amino-acid peptide encoded by a short open reading frame nested within the 12S ribosomal RNA gene of the mitochondrial genome. Identified in 2015, it activates AMP-activated protein kinase through inhibition of the folate cycle, and translocates to the nucleus under metabolic stress to regulate nuclear gene expression.

Key facts

Full name: Mitochondrial ORF of the 12S rRNA type-c
Length: 16 amino acids
Sequence: H-MRWQEMGYIFYPRKLR-OH
Molecular weight: 2,174.6 Da
Molecular formula: C101H152N28O22S2
CAS number: 1627580-64-6
PubChem CID: 146675088
Identified: 2015 — Lee et al., Cell Metabolism

What makes MOTS-c unusual

Almost every peptide studied in this field is encoded in nuclear DNA and translated in the cytosol. MOTS-c is not. Its coding sequence sits inside the mitochondrial genome — specifically within the 12S ribosomal RNA gene, in a short open reading frame that overlaps a gene already doing another job. That places it in a small class of mitochondrial-derived peptides, and it means the mitochondrion is acting as a signalling organelle rather than only a site of energy metabolism.

Where it came from

MOTS-c was identified by Changhan Lee, Jiali Zeng, Brian Drew and colleagues at the University of Southern California, published in Cell Metabolism on 3 March 2015 under the title 'The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance' (PMID 25738459). The paper described both the peptide and its metabolic effects in mouse models.

Research material referenced

MOTS-C 10mg — third-party HPLC tested

View — £24.99

How it signals

MOTS-c activates AMP-activated protein kinase, but not through the canonical route of a rising AMP-to-ATP ratio. It inhibits the folate cycle and de novo purine biosynthesis, which causes AICAR — 5-aminoimidazole-4-carboxamide ribonucleotide, an endogenous AMPK activator — to accumulate. AMPK activation follows from that accumulation. Downstream effects reported in the literature include GLUT4 translocation.

The nuclear finding

In 2018 the same group reported something less expected: under metabolic stress, MOTS-c moves from the mitochondrion into the nucleus and regulates nuclear gene expression, including antioxidant response element-containing genes (Kim, Son and Benayoun, Cell Metabolism, 4 September 2018, PMID 29983246). A peptide encoded in mitochondrial DNA that acts on nuclear transcription is a genuinely two-way channel between the two genomes.

The exercise connection

Reynolds and colleagues reported in Nature Communications on 20 January 2021 (PMID 33473109) that MOTS-c is exercise-induced, with skeletal-muscle levels rising roughly 12-fold and circulating levels about 1.6-fold in humans following exercise. The paper characterised it as a regulator of age-dependent physical decline and muscle homeostasis, with the interventional work conducted in mice.

Where the literature stands

MOTS-c appears in roughly 250 indexed PubMed records. The great majority are preclinical — cell models and rodent studies — alongside human observational work on circulating concentrations. It is not an approved medicine in any jurisdiction and is supplied for laboratory research only.

Extended research context

The MOTS-c (Mitochondrial Peptide) deep dive

Deep dive: why a peptide encoded in mitochondrial DNA is unusual

The human mitochondrial genome is 16,569 base pairs encoding 37 genes, and was considered fully characterised by the 1980s: thirteen respiratory-chain proteins, twenty-two transfer RNAs, two ribosomal RNAs. MOTS-c is encoded by a short open reading frame nested inside the 12S rRNA gene — sequence already annotated as doing something else, which is exactly why it went unnoticed. Humanin, found in 2001 inside the 16S rRNA gene, established that the genome held more than its annotation suggested; MOTS-c was found in 2015 by looking deliberately. The implication is that the mitochondrion encodes and releases signalling molecules of its own, rather than only executing instructions sent from the nucleus.

Deep dive: AMPK activation without touching AMPK

AMPK is normally activated when AMP and ADP bind its gamma subunit, making it a direct sensor of the AMP-to-ATP ratio. MOTS-c does not raise that ratio and does not bind the kinase. It inhibits the folate cycle, the one-carbon pathway feeding de novo purine biosynthesis, and the intermediate AICAR accumulates as a result. AICAR is an AMP mimetic — phosphorylated to ZMP, it binds the same regulatory site AMP occupies. So the peptide reaches a cytosolic energy sensor through one-carbon metabolism and a diffusible small molecule, which is a materially different architecture from a receptor-ligand interaction, and different again from metformin's inhibition of complex I.

Deep dive: reading a preclinical literature honestly

Roughly 250 indexed papers exist, and the overwhelming majority are cell and rodent studies. Where humans appear, the work is generally observational: measuring circulating concentrations and correlating them with age, fitness or metabolic state. The 2021 Nature Communications paper is the clearest example of the structure — the human arm measured MOTS-c before and after exercise, finding roughly a 12-fold rise in skeletal muscle against 1.6-fold in circulation, while the interventional work was done in mice. Two inferences the secondary literature routinely makes and the primary literature does not support: that a correlation between low concentrations and poor metabolic health establishes direction, and that a molecule which rises during exercise would reproduce exercise if administered.

Research applications

▸Study of mitochondrial-derived peptides and retrograde signalling
▸AMPK pathway research through non-canonical activation
▸One-carbon and folate-cycle metabolism models
▸Exercise physiology and mitochondrial bioenergetics research
▸Ageing biology and mitochondrial genome expression studies

Handling checklist

✓Store lyophilised material cold, dry and protected from light
✓Expect methionine oxidation as the primary degradation route (+16 Da per residue)
✓No reducing agent needed — the sequence contains no cysteine
✓Introduce diluent gently against the vial wall; swirl rather than shake
✓Aliquot to avoid repeated freeze-thaw cycles
✓Check mass spectrometry for +16 and +32 satellites before relying on a batch

Common research-handling mistakes

Learnt from thousands of researcher orders across our UK labs.

✗ Reading exercise induction as proof that administration mimics exercise

Fix: The papers report that exercise raises MOTS-c. The reverse inference is not supported and is not claimed.

✗ Treating human observational data as interventional evidence

Fix: Human work measures endogenous concentrations; administration studies were conducted in mice.

✗ Assuming MOTS-c has a cell-surface receptor like humanin

Fix: No receptor is established. Its characterised activity is intracellular.

✗ Storing reconstituted material as though it were as stable as the powder

Fix: Solution-phase material is subject to hydrolysis and oxidation; the lyophilised form is far more stable.

✗ Overlooking WADA status in athlete-adjacent research

Fix: MOTS-c is on the prohibited list; this is relevant to any research context involving competitors.

Continue researching

Peer-reviewed guides, comparators and matched reference materials.

Frequently asked questions

What does MOTS-c stand for?: Mitochondrial Open Reading Frame of the 12S rRNA type-c, which describes exactly where in the mitochondrial genome its coding sequence sits.
Is MOTS-c a hormone?: It is often described as one because it is released and acts at a distance, but it is more precisely a mitochondrial-derived signalling peptide. The distinction matters mainly because its origin is mitochondrial DNA rather than the nuclear genome.
Is MOTS-c approved for any use?: No. It holds no marketing authorisation anywhere and is supplied for laboratory research only.
Is MOTS-c on the WADA prohibited list?: Yes. It is prohibited in sport, which is worth knowing for anyone whose research context involves competitive athletes.

Primary sources & clinical trials

Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.

Written and reviewed by

Jack Muncaster · Founder, UK Peptides

Jack founded UK Peptides in Manchester after repeatedly receiving research compounds with missing or recycled paperwork. He is responsible for supplier selection, batch release decisions and the content published in this research library. Every article here is sourced to primary literature and every product page to a signed third-party certificate.

How we write and check this content Report a factual error in this article

More MOTS-c (Mitochondrial Peptide) articles

Popular across the research hub

One flagship guide from every other research category — keep exploring.

← Back to Forum