Mitochondrial Signaling and Mitochondrial-Derived Peptides

Direct overview

Mitochondria are the parts of cells that make most of a cell's usable energy. They also send messages to the rest of the cell and to other tissues. Two different ideas are often mixed together online and are kept apart here:

1. Mitochondrial-derived peptides (MDPs): small peptides the body itself makes from mitochondrial DNA, such as humanin and MOTS-c.
2. Mitochondria-targeted drugs: synthetic molecules designed to act on mitochondria, such as elamipretide. It is not made from mitochondrial DNA.

A product sold under an MDP's name, a research molecule and an approved drug are three different things. This page is biology and evidence only, not advice to use any of them.

Mitochondria as signaling hubs

Mitokines are signals that carry news of mitochondrial stress to distant cells and tissues. They include FGF21, GDF15 and some MDPs including humanin. A 2023 review notes that levels change with ageing, but whether the changes drive ageing or are "rescue" responses remains to be shown, and that excessive levels are linked to conditions such as cancer and heart failure. [1] In other words, higher is not automatically better.

The endogenous peptides

Eight MDPs have been identified. MOTS-c is encoded in the mitochondrial gene for 12S ribosomal RNA; the other seven (humanin and SHLP1 to 6) come from the 16S ribosomal RNA gene. [2] In humans, lower circulating MDP levels have been associated with obesity, diabetes and ageing, and muscle MDP expression rises in response to stressors such as exercise. [2]

Evidence by kind:

• Cells and animals: treating rodents with humanin, MOTS-c or SHLP2 improved insulin sensitivity and offered protection in models of age-related metabolic disorders. [2] MOTS-c is described as acting through the folate, AICAR and AMPK pathway and moving into the cell nucleus under stress. [3] Humanin improved cognition in aged mice. [4] Label: preclinical.


• Human observation: in a small exercise study (30 people in three groups), a session of endurance exercise raised circulating humanin, while resistance exercise did not, and MOTS-c showed only a trend. Plasma levels did not track fitness measures. [5] In a large cohort, a genetic variant linked to lower humanin levels was associated with faster cognitive aging. [4] These are associations; they do not show that taking a peptide improves anything. Label: insufficient evidence.


• Human treatment trials: we searched PubMed and Europe PMC (title and clinical-trial filters, 2026-10-22) for trials giving MOTS-c or humanin to people and found none reporting clinical outcomes; the relevant records returned measured natural levels rather than giving the peptide. The FDA likewise reports no human exposure data for MOTS-c in compounded drugs. [6] Proper evidence not found. Details on the compounds are on the MOTS-c and humanin pages.

Elamipretide: a synthetic mitochondria-targeted drug

The FDA label for Forzinity (elamipretide) describes a "mitochondrial cardiolipin binder" and gives its peptide sequence as D-Arg-2,6-dimethyl-Tyr-Lys-Phe-NH2, which includes a D-form arginine. [7] It is indicated, under accelerated approval, to improve muscle strength in adults and children with Barth syndrome who weigh at least 30 kg, based on knee extensor strength, an intermediate clinical endpoint; continued approval may depend on a confirmatory trial. [7]

The label's trial details show why this matters: in the randomized crossover trial of 12 people, elamipretide was not superior to placebo on its primary endpoints (walk distance and a fatigue score), and strength increases were seen in the open-label extension, not in the randomized period. [7] In a phase 3 trial of 218 people with primary mitochondrial myopathy, elamipretide did not meet its primary endpoints (6-minute walk difference -3.2 meters, 95% CI -18.7 to 12.3). [8] In rats with a heart failure model, it improved muscle function, an animal result only. [9] Label: approved medicine (FDA, Barth syndrome, accelerated approval); no good evidence of benefit in primary mitochondrial myopathy from that trial; preclinical for other uses.

Related guides

Mitochondria and oxidative stress in aging, SS-31 (elamipretide) and peptides and mitochondrial disorders.