MOTS-c vs Humanin

Origin and structure

MOTS-c is a 16-amino-acid peptide encoded within the mitochondrial 12S ribosomal RNA gene, identified in 2015 by Changhan Lee, Pinchas Cohen and colleagues at USC. Humanin is a 24-amino-acid peptide encoded within the separate 16S rRNA gene, and was the first MDP ever identified — isolated in 2001 by Hashimoto and colleagues from surviving neurons in an Alzheimer's patient's occipital cortex. Both peptides therefore originate from the mitochondrial genome rather than nuclear DNA, but from different ribosomal RNA loci.

Because they were discovered independently and roughly 14 years apart, MOTS-c and Humanin are best understood as siblings within the same peptide family rather than as variants of a single compound. Their amino-acid sequences share no meaningful homology beyond both being short, cationic and mitochondrially encoded.

Mechanism

MOTS-c is principally a metabolic regulator. It activates AMPK in skeletal muscle, increases GLUT4-mediated glucose uptake, and — per Kim et al. (2018) — translocates to the nucleus under metabolic stress to bind chromatin at antioxidant-response elements. Its profile is regularly described as an endogenous exercise-mimetic.

Humanin acts through an extracellular receptor complex (FPRL1/CNTFR/WSX-1) triggering STAT3 signalling, and intracellularly through direct binding to pro-apoptotic Bax, Bid and BimEL. Its principal role is cytoprotective — blocking apoptosis under cellular stress — with a secondary metabolic role in insulin sensitisation.

Evidence base

Both peptides show plasma decline with age and reduced circulating levels in type 2 diabetes, a pattern first characterised for Humanin by Yen et al. (2014) and subsequently reported for MOTS-c by Lu et al. (2016-17). Both have preclinical support from multiple independent groups internationally rather than a single originating laboratory, which distinguishes them from many Khavinson-programme peptides covered elsewhere on this site.

Humanin has the longer research history (discovery in 2001 versus 2015 for MOTS-c) and a correspondingly larger published literature, including disease-model work in Alzheimer's, ischaemic stroke and atherosclerosis. MOTS-c's literature is more concentrated on metabolic and exercise-physiology endpoints, reflecting its more recent characterisation and narrower initial research focus.

Research positioning

MOTS-c is studied as a probe of mitokine-mediated metabolic regulation — a candidate mechanism for age-related insulin resistance, sarcopenia and the metabolic benefits of exercise. Humanin is studied as a broader stress-response mitokine with cytoprotective, neuroprotective and metabolic roles spanning several disease contexts. Both are framed in the literature as evidence that the mitochondrial genome encodes signalling peptides with systemic, hormone-like activity — a finding that has reshaped how mitochondrial biology is understood in ageing research.

Summary table

For the full evidence base, see the individual pages: Read the full MOTS-c entry and Read the full Humanin entry.