MOTS-c: What the Mitochondrial Peptide Research Shows

For decades, biologists assumed the tiny genome inside mitochondria held no surprises: 37 genes for running the cell’s power plants, and nothing else. MOTS-c broke that assumption. Discovered in 2015, it is a 16-amino-acid peptide encoded in mitochondrial DNA that travels out of the mitochondria to act as a signal elsewhere, and it has since become one of the most-searched peptides in metabolic and ageing research.

This guide covers what MOTS-c is, how it was found, what the cell, animal and human studies show, where the evidence stops, and what to check when sourcing research-grade MOTS-c in Canada.

A peptide hidden in mitochondrial DNA

Mitochondria carry their own small circle of DNA, a relic of their bacterial ancestry. Its genes were thought to be fully mapped. Then, in 2001, researchers in Japan found humanin, a short peptide whose code sits inside the mitochondrial 16S ribosomal RNA gene. That opened a search for more of these hidden “mitochondrial-derived peptides”.

In 2015, Changhan Lee and Pinchas Cohen’s team at the University of Southern California reported a second family member, encoded within the 12S ribosomal RNA gene. They named it MOTS-c and showed in mice that it improved insulin sensitivity and protected against diet-induced obesity. Our overview of MOTS-c, SS-31 and humanin compares the three best-known mitochondrial peptides.

1. 2001Humanin, the first mitochondrial-derived peptide, is reported from a screen for factors that protect neurons.
2. 2015MOTS-c is described in Cell Metabolism as a regulator of metabolic homeostasis in mice.
3. 2018The same group shows MOTS-c moves into the nucleus under metabolic stress and regulates protective genes.
4. 2021A study in Nature Communications links MOTS-c to exercise in humans and to physical capacity in ageing mice.
5. 2023CohBar, the company developing a MOTS-c analogue called CB4211, winds down without completing late-stage trials.

How MOTS-c works in cells

MOTS-c’s best-documented effect is on AMPK, the enzyme cells use to sense low energy and shift toward burning fuel. Rather than changing the cell’s energy balance directly, MOTS-c slows the folate cycle and part of purine production, which causes a natural AMPK activator called AICAR to build up. In muscle cells, the result looks like a mild version of the metabolic signal exercise produces.

Under metabolic stress, MOTS-c also travels from the cytoplasm into the nucleus, where it helps switch on genes with antioxidant response elements, part of the cell’s defence against oxidative stress. That makes it an unusual example of a mitochondrial gene product directly influencing the nuclear genome.

The exercise connection

The 2021 study, led by Joseph Reynolds with Changhan Lee, measured MOTS-c in people before and after exercise and found that levels rose in skeletal muscle and in the blood. In mice, MOTS-c treatment improved physical performance in young, middle-aged and old animals, including when treatment started late in life. That is why MOTS-c is often described as an “exercise mimetic” in research literature.

The label needs care. The human finding is that the body makes more of its own MOTS-c during exercise; it is not evidence that giving MOTS-c reproduces the benefits of exercise in people. For a similar story about a small molecule, see our guide to SLU-PP-332.

The human evidence gap

Most of what is known comes from cell and mouse studies by a relatively small group of laboratories. In humans, the evidence is observational: measurements of natural MOTS-c levels, which differ with age, metabolic health and exercise. A naturally occurring variant, K14Q, in which lysine 14 is replaced by glutamine, is found mainly in people of Northeast Asian ancestry and has been associated with type 2 diabetes risk in a Japanese genetic study.

The closest thing to a drug programme was CohBar’s CB4211, a modified MOTS-c analogue tested in early-phase trials for fatty liver disease and obesity. It did not progress to late-stage trials before the company wound down in 2023, so no MOTS-c-based therapy has been approved.

What is established and what is open

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Sourcing MOTS-c in Canada

Before ordering MOTS-c from any supplier, check that:

• The mass matches, at about 2,175 g/mol. With two methionines, an extra 16 or 32 g/mol usually means oxidation. See our HPLC testing guide.
• The sequence is the 16-residue human form, not the K14Q variant or an analogue such as CB4211, unless your study calls for one. Our amino acid code chart helps you read it.
• The COA matches your lot. See our peptide COA guide.
• Storage is cold, dry and dark to protect the methionines. See our peptide stability guide.

Frequently asked questions