MOTS-c: what the mitochondrial peptide is and what it is for

What MOTS-c is

MOTS-c stands for mitochondrial open reading frame of the 12S rRNA type-c. It is one of the mitochondrial-derived peptides: small peptides encoded in mitochondrial DNA. A 2020 review counted eight, among them MOTS-c and humanin.

Its human sequence is MRWQEMGYIFYPRKLR (16 amino acids), with a mass of about 2174.6 g/mol (PubChem CID 146675088). It has two methionines and a tryptophan, which matters for storage.

What MOTS-c is used for

What is known comes from laboratory research, not treatment:

• In 2018 a University of Southern California laboratory reported that MOTS-c moves into the cell nucleus under metabolic stress (such as glucose restriction), in an AMPK-dependent way, and regulates antioxidant-response genes there.
• A 2020 review reported that in people, muscle expression of these peptides rises with stresses that perturb mitochondria, such as exercise.
• Rodent studies with synthetic MOTS-c describe effects in particular models that cannot be carried over to people.

That is why social media calls it "the exercise peptide" or links it to weight loss and longevity. None of those uses has published controlled trials in people.

What FDA says

There is no approved MOTS-c product. When it was nominated for compounding, FDA placed it in category 2 (substances that may present significant safety risks), citing possible immunogenicity and difficulty characterizing its impurities, and noted it has identified no human exposure data. The nominations were later withdrawn. MOTS-c was also on the agenda of FDA’s compounding advisory committee in July 2026; as of October 2026 no decision had been published.

In sport, anti-doping agencies watch for it: a laboratory published a validated method to detect it in plasma in 2019.

MOTS-c side effects

They are not known with certainty, precisely because there are no controlled trials in people. The concerns FDA mentions are a possible immune response (immunogenicity) and the impurities of a synthetic peptide. Any list of "side effects" on social media does not come from a clinical trial.

Another point: measurements of the body’s own MOTS-c are uncertain too. When a mass spectrometry method was compared with a commercial ELISA, the measured levels differed widely.

What to check on a MOTS-c COA

• Identity by mass spectrometry, with a mass of about 2174.6 g/mol. Each peak 16 Da heavier means one added oxygen (oxidation of a methionine or the tryptophan).
• Purity by HPLC, with oxidation products reported as impurities.
• Species: that it is the human sequence, not an animal analogue.
• Salt and net peptide content.

Certificates for our MOTS-c are published by lot in the COA library.