The mitochondrial peptide MOTS-c improved physical performance in mice of all ages — including when started very late in life — and exercise naturally boosts MOTS-c levels in human muscle and blood.
Late-life effectiveMOTS-c treatment started at 23.5 months (very old age in mice) with just 3x/week dosing still improved physical capacity and healthspan
What the researchers found
MOTS-c, a peptide encoded by mitochondrial DNA, significantly enhanced physical performance in young (2 months), middle-aged (12 months), and old (22 months) mice. Most remarkably, when MOTS-c treatment was started very late in life (23.5 months — equivalent to roughly 70+ human years) at just 3 times per week, it still increased physical capacity and healthspan.
The study also showed that exercise naturally increases MOTS-c levels in both skeletal muscle and blood circulation in humans, establishing MOTS-c as an exercise-induced factor. At the molecular level, MOTS-c regulates nuclear genes related to metabolism and protein quality control (proteostasis), directly affects skeletal muscle metabolism, and helps muscle cells (myoblasts) adapt to metabolic stress.
Why it matters
This is one of the most important MOTS-c studies published because it demonstrates three critical things: (1) a mitochondrial-encoded peptide can actively regulate the aging process, (2) even late-life treatment can improve physical function, and (3) exercise naturally produces MOTS-c in humans. The finding that intermittent MOTS-c treatment started in very old mice still improved healthspan challenges the assumption that anti-aging interventions must start early to be effective. It also positions MOTS-c as a potential exercise mimetic for people who cannot exercise.
The numbers in context
Enhanced performance in mice at 2, 12, and 22 months · late-life treatment started at 23.5 months · 3x/week intermittent dosing · exercise induces MOTS-c in human muscle + circulation · regulates nuclear gene expression
How the study worked
Multi-component study combining mouse experiments and human exercise data. Mice at three age groups received MOTS-c and were tested for physical performance. A separate cohort started treatment at 23.5 months (late life) with intermittent 3x/week dosing. In humans, skeletal muscle biopsies and blood samples were collected before and after exercise to measure endogenous MOTS-c levels. Molecular analyses included gene expression profiling, metabolomics in skeletal muscle, and myoblast stress response assays.
Who was studied
C57BL/6 mice at young, middle-aged, and old ages; adult human exercise volunteers for endogenous MOTS-c measurement
What this study cannot tell us
While MOTS-c improved physical capacity in mice, the study does not fully characterize all aspects of healthspan (cognitive function, organ-specific aging, etc.). The human component confirms that exercise induces MOTS-c but does not test exogenous MOTS-c administration in humans. Specific dosing details and the magnitude of physical performance improvements are not detailed in the abstract. Long-term safety of exogenous MOTS-c in any species remains to be established. The mechanisms by which a mitochondrial-encoded peptide regulates nuclear gene expression are still being elucidated.
How to read the evidence
Published in Nature Communications, this study combines rigorous mouse experiments across multiple age groups with human exercise data. The 'Strong' grade reflects the high-impact journal, the comprehensive age-spanning design, and the inclusion of both animal and human components.
When this study was published
Published in 2021, this is a recent and highly influential study. It built on earlier MOTS-c research from the same group (Cohen/Lee labs) and has become one of the most-cited papers in the mitochondrial-derived peptide field.
The bigger picture
MOTS-c belongs to a newly discovered class of peptides encoded by mitochondrial DNA — challenging the old view that mitochondria are just energy factories. This study from Nature Communications positions MOTS-c as a genuine exercise mimetic and aging regulator. The finding that late-life treatment still works is particularly significant for the aging research field, which has long debated whether interventions must start early. MOTS-c is now one of the most studied mitochondrial-derived peptides, alongside humanin.
Questions still open
- Could exogenous MOTS-c administration improve physical function in elderly or frail humans who cannot exercise?
- What is the optimal dosing regimen for MOTS-c to maximize healthspan benefits while minimizing any risks?
- How does MOTS-c communicate from the mitochondria to the nucleus to regulate gene expression — what is the signaling pathway?
Common questions
What is MOTS-c and where does it come from?
Does this mean MOTS-c could replace exercise?
Read the original research
MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis.
Nature communications, 12(1), 470
Citation
Reynolds, Joseph C; Lai, Rochelle W; Woodhead, Jonathan S T; Joly, James H; Mitchell, Cameron J; Cameron-Smith, David; Lu, Ryan; Cohen, Pinchas; Graham, Nicholas A; Benayoun, Bérénice A; Merry, Troy L; Lee, Changhan. (2021). MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis.. Nature communications, 12(1), 470. https://doi.org/10.1038/s41467-020-20790-0