Two Peptides, One Target
MOTS-c and SS-31 are both mitochondria-targeting research peptides, but they reach the mitochondrion through different routes and act on different components. MOTS-c is a mitochondrial-derived peptide encoded in the mitochondrial genome — it regulates nuclear gene expression and metabolic homeostasis. SS-31 (elamipretide) is a synthetic tetrapeptide that concentrates in the inner mitochondrial membrane and protects cardiolipin, a structural lipid essential for electron transport chain function. Same organelle, fundamentally different biology.
All products sold by FenaLife are intended strictly for laboratory and academic research purposes. Not for human consumption, injection, or ingestion. These statements have not been evaluated by the FDA.
Compound Profiles
| Property | MOTS-c | SS-31 (Elamipretide) |
|---|---|---|
| Full Name | Mitochondrial Open Reading Frame of the 12S rRNA Type-c | Szeto-Schiller Peptide 31 |
| Structure | 16 amino acids | 4 amino acids (Arg-2′6′-Dmt-Lys-Phe-NH₂) |
| Origin | Encoded in mitochondrial 12S rRNA | Synthetic — designed for mitochondrial targeting |
| Primary Target | AMPK pathway, nuclear gene expression, metabolic regulation | Cardiolipin on inner mitochondrial membrane |
| Mechanism | Retrograde mitochondria-to-nucleus signalling (mitohormesis) | Cardiolipin stabilisation, electron transport chain protection |
| Half-Life | Short — hours | Very short — minutes (rapid tissue uptake) |
Mechanisms: Cardiolipin vs AMPK
SS-31: Cardiolipin Protection
SS-31’s alternating aromatic-cationic structure allows it to concentrate approximately 1000-fold in the inner mitochondrial membrane, driven by the membrane potential. Once there, it binds to cardiolipin — a phospholipid unique to the inner mitochondrial membrane that anchors and organises the electron transport chain (ETC) complexes. Under oxidative stress, cardiolipin oxidation destabilises ETC complexes, reduces ATP production, and releases cytochrome c (triggering apoptosis). SS-31 protects cardiolipin from oxidation, preserving ETC structure and function, reducing reactive oxygen species (ROS) production, and blocking the cytochrome c release pathway.
MOTS-c: Mitochondrial Retrograde Signalling
MOTS-c is not a structural protector — it is a signalling peptide. Under metabolic stress (exercise, caloric restriction, hypoxia), MOTS-c is released from mitochondria into the cytoplasm and translocates to the nucleus, where it activates stress response elements and upregulates AMPK-dependent gene expression. In rodent models this produces insulin sensitisation, reduced adiposity, enhanced exercise capacity, and anti-inflammatory gene transcription. It functions as a mitohormetic signal — a message from mitochondria to the nucleus to adapt metabolic programming.
Research Applications Comparison
| Research Area | MOTS-c | SS-31 |
|---|---|---|
| Metabolic dysfunction / insulin resistance | Strong — AMPK activation, glucose uptake | Indirect — improved ETC efficiency |
| Cardiac protection (ischemia-reperfusion) | Some data | Strong — the primary application in clinical trials |
| Skeletal muscle & exercise performance | Strong — increases endurance, muscle mass in aged models | Moderate — mitochondrial biogenesis support |
| Longevity / aging biology | Strong — circulating MOTS-c declines with age | Moderate — age-related mitochondrial decline |
| Renal protection | Limited data | Strong — acute kidney injury models, clinical trials |
| Neuroprotection | Emerging data | Moderate — reduces neuronal ROS |
| Barth syndrome / primary mitochondrial disease | Not studied | Phase 2/3 clinical trials completed |
| Eye / retinal disease | Limited | Phase 2 trials (dry AMD, LHON) |
Clinical Trial Status
SS-31 has the more advanced clinical trial profile. Stealth BioTherapeutics conducted Phase 2/3 trials for heart failure with preserved ejection fraction (HFpEF), Barth syndrome, and Leber’s hereditary optic neuropathy (LHON). The HFpEF trial (PROGRESS-HF) did not meet its primary endpoint, though secondary endpoints showed functional improvements. Barth syndrome results were more encouraging. SS-31 remains in development under the name elamipretide.
MOTS-c research is primarily preclinical. Human data is limited to observational studies showing circulating MOTS-c correlates with metabolic health, exercise capacity, and healthy aging in elderly populations. Clinical interventional trials are early-stage.
Which Compound for Which Research Question?
Use MOTS-c for research questions involving metabolic regulation, insulin sensitivity, AMPK signalling, exercise biology, or age-related decline in mitochondrial retrograde signalling. MOTS-c is the correct choice when the research question is about how mitochondria communicate metabolic status to the rest of the cell.
Use SS-31 for research questions involving mitochondrial structural integrity, cardiolipin biology, ischemia-reperfusion injury, cardiac protection, acute kidney injury, or any model involving acute oxidative stress and ETC dysfunction. SS-31 is the correct choice when the research question is about protecting mitochondrial architecture under stress.
Frequently Asked Questions
Can MOTS-c and SS-31 be studied together?
There is no published preclinical data on the combination. Mechanistically, they operate at different points of mitochondrial biology — SS-31 protects structure while MOTS-c modulates signalling — so complementarity is plausible. Researchers interested in comprehensive mitochondrial health models may find both compounds relevant.
Does MOTS-c decline with age?
Yes. Observational data in humans shows circulating MOTS-c levels decline with age and are lower in individuals with type 2 diabetes and obesity. This has made it a subject of longevity and metabolic aging research.
Is SS-31 available as a research compound?
Yes. SS-31 (elamipretide) is available as a research peptide. FenaLife carries longevity research compounds including MOTS-c.
What is cardiolipin and why does it matter?
Cardiolipin is a phospholipid found almost exclusively in the inner mitochondrial membrane. It is essential for organising the ETC supercomplexes (respirasomes) that produce ATP. When cardiolipin is oxidised — as occurs during ischemia, aging, and oxidative stress — ETC efficiency drops, ROS production rises, and apoptotic signalling is triggered via cytochrome c release. SS-31 prevents cardiolipin oxidation, preserving this entire cascade.
Is MOTS-c the same as humanin?
No. Both are mitochondrial-derived peptides (MDPs) encoded in the mitochondrial genome, but they are different peptides with different sequences and mechanisms. Humanin (encoded in the 16S rRNA region) has neuroprotective and cytoprotective effects. MOTS-c (encoded in the 12S rRNA region) primarily regulates metabolism and AMPK signalling. They are members of the same MDP family but are not interchangeable.
Source MOTS-c at FenaLife
FenaLife supplies MOTS-c in the Longevity Research category with Janoshik third-party COA. Free shipping on orders over $100.
All products sold by FenaLife are intended strictly for laboratory and academic research purposes. Not for human consumption, injection, or ingestion. These statements have not been evaluated by the FDA.
🔬 Research Compounds Referenced: MOTS-c 10mg | SS-31 10mg