MOTS-c vs SS-31: Mitochondrial Research Peptide Comparison
MOTS-c vs SS-31: Mitochondrial Research Peptide Comparison
Research peptides for laboratory use only. Not approved by the FDA. Not for human consumption. By purchasing, you confirm you are a qualified researcher operating in a controlled laboratory setting.
Overview
MOTS-c and SS-31 are two of the most-cited research peptides in the mitochondrial-research category. Both target mitochondrial biology, but the mechanistic similarity ends there. MOTS-c is a mitochondrial-DNA-encoded peptide acting through a metabolic-signaling axis. SS-31 is a synthetic tetrapeptide acting through a structural lipid-binding axis. They are different molecules answering different research questions, both meaningful, neither substitutable for the other.
Mechanism Contrast
MOTS-c
MOTS-c, or Mitochondrial Open Reading Frame of the 12S rRNA-c, is a 16-amino-acid peptide encoded by the mitochondrial genome itself. It is one of a small set of mitochondria-derived peptides identified in published literature. The mechanistic emphasis in MOTS-c research is on the AMP-activated protein kinase (AMPK) pathway and on metabolic signaling between mitochondria and the rest of the cell. In animal models, MOTS-c has been studied in metabolic, exercise-physiology, and aging contexts.
SS-31 (Elamipretide)
SS-31, also known as elamipretide, is a synthetic four-amino-acid peptide of the Szeto-Schiller class. The mechanistic emphasis is on cardiolipin binding within the inner mitochondrial membrane. By binding cardiolipin, SS-31 has been studied in published literature for its effect on electron transport chain efficiency, reactive oxygen species generation, and cristae structure preservation. The research-context applications cluster around mitochondrial-dysfunction models.
Pathway Differences
MOTS-c is a signaling peptide. The published mechanistic axis is AMPK activation, with downstream effects on glucose metabolism, fatty acid oxidation, and mitochondrial biogenesis pathways. The peptide acts as a metabolic regulator rather than a structural component.
SS-31 is a structural-targeting peptide. The published mechanistic axis is cardiolipin binding within the inner mitochondrial membrane, with downstream effects on electron-transport-chain organization and on reactive oxygen species rates. The peptide acts as a localized structural stabilizer rather than a metabolic signaler.
Both peptides are studied for mitochondrial-related research outcomes, but the underlying intervention is mechanistically distinct. A research design comparing the two should treat them as orthogonal interventions, not as alternatives in the same intervention class.
Side-by-Side Spec Comparison
| Spec | MOTS-c | SS-31 |
|---|---|---|
| Sequence length | 16 amino acids | 4 amino acids |
| Origin | Mitochondrial-DNA-encoded | Synthetic Szeto-Schiller class |
| Approximate molecular weight | ~2,174 Da | ~640 Da |
| Mechanistic axis | AMPK pathway, metabolic signaling | Cardiolipin binding, ETC stabilization |
| Research-context emphasis | Metabolic, exercise, aging | Mitochondrial dysfunction models |
| PCA vial size | 40mg | 50mg |
Research Context
MOTS-c sits in a research lineage that frames mitochondria as a signaling organelle, generating peptides that communicate cellular state to the broader metabolic machinery. The published preclinical work emphasizes AMPK activation as the proximal mechanism and downstream metabolic adaptation as the distal observation.
SS-31 sits in a research lineage that frames mitochondrial dysfunction as a treatable structural problem, where the inner-membrane lipid environment is the intervention point. The published preclinical work emphasizes cardiolipin association as the proximal mechanism and electron-transport-chain efficiency as the distal observation.
For research operators studying mitochondrial biology, the two peptides answer different questions. A research design choosing between them should match the peptide to the research question rather than treat them as substitutable.
Reconstitution Math
MOTS-c 40mg: reconstituted with 4 mL of bacteriostatic water yields 10 mg/mL. With 2 mL, 20 mg/mL. A 0.05 mL draw at 10 mg/mL is 500 mcg.
SS-31 50mg: reconstituted with 5 mL yields 10 mg/mL. With 2.5 mL, 20 mg/mL. A 0.05 mL draw at 10 mg/mL is 500 mcg.
These figures are arithmetic conversions of label mass to per-volume concentration for research compounding records. They are not protocol guidance.
PCA SKUs in This Category
Documentation Standard
Every MOTS-c and SS-31 lot shipped from Pure Chain Aminos carries a per-batch certificate of analysis with HPLC purity verification and mass spectrometry identity confirmation. Lot identifier on the COA matches the bottle. Method documentation is on the COA. (Dedicated SS-31 research detail page coming soon.)
Get Started With WELCOME20
New researchers receive 20% off their first qualifying order with code WELCOME20 ($75 minimum). Browse MOTS-c 40mg and SS-31 50mg, or browse the full Pure Chain Aminos catalog.
Research peptides for laboratory use only. Not approved by the FDA. Not for human consumption. By purchasing, you confirm you are a qualified researcher operating in a controlled laboratory setting.
Mechanism Comparison Table
MOTS-c and SS-31 are both mitochondrial-focused research peptides studied for distinct mechanisms. The summary table below frames how researchers contrast the two compounds before designing a study.
| Attribute | MOTS-c | SS-31 (elamipretide) |
|---|---|---|
| Source | Endogenous 16-amino-acid mitochondrial-derived peptide encoded in the 12S rRNA region of mitochondrial DNA | Synthetic tetrapeptide D-Arg-Dmt-Lys-Phe-NH2 designed for inner-mitochondrial-membrane targeting |
| Approximate molecular mass | ~2174 Da | ~640 Da |
| Mechanistic focus (research models) | AMPK signaling, metabolic homeostasis, glucose disposal, mitochondrial biogenesis markers | Cardiolipin-binding peptide that stabilizes inner mitochondrial membrane and reduces reactive oxygen species in cell models |
| Reported half-life (animal model literature) | Short systemic half-life; multiple cited research protocols use repeat dosing | Short half-life; rodent literature describes repeat-dose research protocols |
| Storage condition | Lyophilized at 2-8 C; reconstituted with bacteriostatic water; refrigerated post-reconstitution | Lyophilized at 2-8 C; reconstituted with bacteriostatic water; refrigerated post-reconstitution |
Reconstitution Math Worked Example
Worked example assuming each lyophilized vial is reconstituted with 2 mL of bacteriostatic water. Researchers should always verify against COA-stated peptide content.
MOTS-c (Pure Chain Aminos Mot-C 40mg vial) + 2 mL bac water: 40 mg / 2 mL = 20 mg/mL = 20,000 mcg/mL. A 0.05 mL draw represents 1,000 mcg. A 0.10 mL draw represents 2,000 mcg.
SS-31 (Pure Chain Aminos SS-31 50mg vial) + 2 mL bac water: 50 mg / 2 mL = 25 mg/mL = 25,000 mcg/mL. A 0.04 mL draw represents 1,000 mcg. A 0.10 mL draw represents 2,500 mcg.
The Pure Chain Aminos bacteriostatic water reconstitution guide walks through volume selection and aseptic technique step by step.
Stability and Storage Comparison
Both peptides are shipped lyophilized in sealed glass vials and held at 2-8 C until reconstitution. Once reconstituted with bacteriostatic water, both are kept refrigerated. SS-31 has a more compact tetrapeptide structure that holds well in solution under cold storage; the longer MOTS-c sequence is also stable under refrigeration but laboratories running long protocols often aliquot working volumes to limit freeze-thaw cycling. Most cited research protocols use the reconstituted vial within 14-30 days.
Research Literature Snapshot
The selected references below are commonly cited in MOTS-c and SS-31 research planning. Citations are provided for literature awareness only and make no efficacy claim.
- Lee C et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metabolism, 2015. PMID: 25738459.
- Reynolds JC et al. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nature Communications, 2021. PMID: 33446655.
- Szeto HH. First-in-class cardiolipin-protective compound as a therapeutic agent to restore mitochondrial bioenergetics. British Journal of Pharmacology, 2014. PMID: 24773457.
- Birk AV et al. The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin. Journal of the American Society of Nephrology, 2013. PMID: 23393318.
- Kim KH, Son JM et al. Mitochondrial-derived peptides as signaling molecules. Journal of Molecular Biology, 2018 (review). PMID: 29746851.
Researcher Considerations
MOTS-c is more frequently selected in research models exploring AMPK signaling, exercise-mimetic pathways, or metabolic-homeostasis questions in rodent models. SS-31 is more frequently selected in research models focused on inner-mitochondrial-membrane integrity, cardiolipin biology, or oxidative-stress markers in cell and tissue models. Where a research design is investigating mitochondrial biology broadly, the two are sometimes studied in parallel arms — but selection should follow the design hypothesis, the published reference model, and committee protocol guidance, not popularity.
FAQ
Are MOTS-c and SS-31 the same class of peptide?
No. MOTS-c is a 16-amino-acid mitochondrial-derived peptide encoded by mitochondrial DNA. SS-31 is a synthetic four-residue tetrapeptide engineered for inner-mitochondrial-membrane targeting. They share a research focus on mitochondrial biology but operate through distinct mechanisms.
How are these peptides typically stored before reconstitution?
Lyophilized vials are stored at 2-8 C, sealed, away from light. After reconstitution with bacteriostatic water, vials are kept refrigerated and most cited research protocols use them within 14-30 days.
Why is SS-31 sometimes called elamipretide in the literature?
Elamipretide is the development-program name used for SS-31 in published clinical research literature. The peptide structure is identical; “SS-31” remains the common research-grade reference name in laboratory studies.
Are these peptides FDA approved?
No. MOTS-c and SS-31 are research-grade reference compounds for laboratory use only and are not FDA approved.
Where can I review published research?
The Pure Chain Aminos MOTS-c research page links curated PubMed citations. SS-31 references are widely available on PubMed under both “SS-31” and “elamipretide” search terms.
Can MOTS-c and SS-31 be reconstituted in the same vial?
No. Each lyophilized vial is reconstituted independently. Researchers running parallel arms keep each peptide in its own labeled vial with the COA on file.
Selected SKU Options
Pure Chain Aminos research-grade SKUs in this category include Mot-C 40mg and SS-31 50mg. For more on vendor selection, see how to evaluate a research peptide vendor and the 2026 research peptide companies guide.
Compliance reminder: research peptides for laboratory use only. Not for human consumption. Citations support literature awareness, not efficacy claims.
