Peptide class
Peptides that interact directly with mitochondrial membranes or mitochondrial signalling pathways, investigated for their potential role in reducing oxidative stress, improving cellular energy production, and addressing mitochondrial dysfunction in aging and disease.
| Compound | Mechanism | Primary Use | Profile |
|---|---|---|---|
| SS-31 (Elamipretide) | Targets cardiolipin in the inner mitochondrial membrane; reduces ROS and improves ATP production | Mitochondrial dysfunction research, heart failure, aging | View profile |
| MOTS-c | Mitochondrial-derived peptide; activates AMPK and regulates nuclear gene expression | Metabolic health, exercise capacity, insulin sensitivity, aging research | View profile |
SS-31 (Szeto-Schiller peptide 31, also called Elamipretide) is a synthetic tetrapeptide (D-Arg-2′6′-Dmt-Lys-Phe-NH₂) that accumulates in the inner mitochondrial membrane (IMM) at concentrations 1000-fold higher than the cytoplasm, driven by its alternating positive charge and aromatic residues. In the IMM it binds cardiolipin — a unique phospholipid almost exclusively found in mitochondrial membranes that is essential for cristae architecture, electron transport chain (ETC) complex assembly, and cytochrome c retention. Cardiolipin oxidation is an early event in mitochondrial dysfunction; SS-31's binding protects it from oxidation and preserves ETC function.
MOTS-c (Mitochondrial Open Reading Frame of the 12S rRNA-c) is a 16-amino acid peptide encoded in the mitochondrial genome itself — specifically in the 12S rRNA region — making it one of the few known mitochondrial-derived peptides (MDPs). Under metabolic stress, MOTS-c translocates from the mitochondria to the nucleus where it regulates nuclear gene expression, particularly pathways governing AMPK activation, glucose uptake, fatty acid metabolism, and antioxidant response. This retrograde mitochondrial-nuclear signalling represents a distinct mechanism from receptor-based peptides.
Mitochondrial dysfunction and accumulation of reactive oxygen species (ROS) is a central feature of the aging process and of numerous age-related diseases including heart failure, neurodegenerative diseases, and metabolic syndrome. Both SS-31 and MOTS-c address mitochondrial pathology through distinct but complementary mechanisms — one by protecting membrane architecture from oxidative damage, the other by activating adaptive gene expression programmes that combat metabolic stress.
SS-31 (Elamipretide) has been in clinical trials for heart failure with preserved ejection fraction (HFpEF), Barth syndrome (a mitochondrial cardiolipin disorder), and primary mitochondrial myopathy. Phase 2 data showed improvement in exercise tolerance in HFpEF patients. It is one of the few peptides in this space with substantial published human clinical data.
MOTS-c was identified in 2015 by Chang et al. at the University of Southern California as a mitochondria-encoded peptide with metabolic regulatory properties. Animal model research has shown beneficial effects on insulin sensitivity, exercise capacity, and obesity-related metabolic parameters. Research has investigated MOTS-c levels in human aging and disease, finding reduced circulating levels in older individuals and in insulin-resistant states.
SS-31 (Elamipretide)
The most clinically advanced mitochondrial-targeting peptide. Its cardiolipin-binding mechanism is well-characterised biochemically. Research in cardiac contexts has been particularly active, given cardiolipin's critical role in cardiac mitochondrial function. Commonly administered via SubQ injection in research contexts, with IV infusion used in some clinical trials.
MOTS-c
A recently discovered mitochondria-encoded peptide whose systemic signalling roles are still being characterised. Research has investigated its potential role in metabolic disease, exercise adaptation, and the biology of aging. Circulating MOTS-c levels have been found elevated in centenarian populations in some studies, generating interest in its longevity-associated biology.