SS-31
InvestigationalAlso known as: Elamipretide, Bendavia, MTP-131
A first-in-class mitochondria-targeting tetrapeptide that binds cardiolipin on the inner mitochondrial membrane. Developed by Stealth BioTherapeutics for mitochondrial diseases, heart failure, and age-related macular degeneration. Phase 3 trials in primary mitochondrial myopathy did not meet primary endpoints, but Barth syndrome data was positive. Strong preclinical rationale with mixed clinical translation.
Research Statistics
Mitochondria-targeted tetrapeptide (elamipretide) in Phase 2-3 trials for primary mitochondrial myopathy and Barth syndrome. US-led trials with some international sites. Cardiolipin-targeting mechanism with mitochondrial cristae stabilization is well-characterized through multiple biochemical studies.
Research Dossier
Overview
What is SS-31 and what does the research say?
Mechanism of Action
The mechanisms of SS-31 have been well-characterized in preclinical and mechanistic studies. Unlike conventional antioxidants, SS-31 targets the source of reactive oxygen species rather than scavenging them after formation.
How It Works (Simplified)
SS-31 is a mitochondria-targeting peptide that optimizes cellular energy production:
Rapidly penetrates cells and concentrates 1,000-5,000x inside mitochondria within minutes, specifically localizing to the inner membrane.
Binds to cardiolipin, a unique phospholipid essential for respiratory complex function, optimizing its interactions with cytochrome c.
Improves electron transport chain efficiency - more ATP produced per oxygen consumed, fewer electrons leak to form damaging superoxide.
Protects cardiolipin from peroxidation, maintains cristae structure, and stabilizes membrane potential to prevent cell death cascades.
Scientific Pathways
Cardiolipin Interaction Mechanism
SS-31 enters cell (minutes)
|
Concentrates 1000-5000x in mitochondria
|
Binds cardiolipin on inner mitochondrial membrane
|
+-- Optimizes cytochrome c binding to cardiolipin
| +-- Enhances electron transfer efficiency
| +-- Reduces electron leak at Complex I and III
|
+-- Protects cardiolipin from peroxidation
| +-- Maintains cristae structure
| +-- Preserves respiratory supercomplex assembly
|
+-- Stabilizes mitochondrial membrane potential
+-- Prevents mPTP opening
+-- Reduces cytochrome c release
+-- Inhibits apoptotic cascadeBioenergetic Improvement Pathway
SS-31 + Cardiolipin binding → Optimized ETC function → Increased ATP/O2 ratio
↓
Reduced ROS production
↓
Protected mitochondrial integrityKey Research: Birk AV et al. (2013) elucidated the cardiolipin binding mechanism. PMID:23813215
Important Limitations
- Phase 3 trials in PMM did not meet primary endpoints despite strong preclinical data
- Clinical translation has been challenging due to heterogeneous patient populations
- Functional endpoints (6MWT) may not capture mitochondrial-specific improvements
- Optimal patient selection biomarkers still being identified
- Human pharmacokinetics differ from plasma half-life due to tissue concentration
Evidence-Chained Benefits
Evidence-Chained Benefits
Research findings linked to mechanisms and clinical outcomes
What to Expect
Timeline based on observations from published studies. Individual responses may vary.
SS-31 rapidly crosses plasma membrane and concentrates 1000-5000x in mitochondria. Binds cardiolipin on inner mitochondrial membrane. In aged mice, single 1-hour treatment showed immediate improvements in mitochondrial function.
Clinical trials used daily SC dosing with steady state achieved within days. Phase 2 trials (28 days) showed trends toward improved cardiac and mitochondrial parameters.
Phase 3 PMM trials evaluated 24-week endpoints. Barth syndrome trial showed significant improvements by 12 weeks. Long-term extension studies (up to 144 weeks) showed durable improvements in completers.
144-week extension data suggests sustained effects. Ongoing ReCLAIM-2 trial evaluating chronic dosing for geographic atrophy. Long-term human pharmacokinetics and optimal treatment duration continue to be characterized.
Research-Based Observations
This timeline reflects observations from published clinical and preclinical studies. Individual responses may vary significantly. This is not a guarantee of effects or a dosing schedule. Consult qualified healthcare providers for personalized guidance.
Quality Checklist
Visual indicators to help evaluate SS-31 product quality
Good Signs (7 indicators)
Warning Signs (5 indicators)
Bad Signs (7 indicators)
For Research Evaluation Only
These quality indicators are general guidelines based on typical peptide characteristics. Professional laboratory testing (HPLC, mass spectrometry) provides definitive quality verification. This checklist is for initial visual evaluation only.
Peptide Interactions
Known and theoretical interactions when combining SS-31 with other peptides. Based on published research and mechanistic considerations.
Mitoq
CompatibleDifferent mitochondrial targets - SS-31 binds cardiolipin on inner membrane while MitoQ accumulates in matrix. May provide complementary antioxidant and bioenergetic effects. No interaction studies available.
Coq10
CompatibleCoQ10 functions as electron carrier in ETC while SS-31 optimizes cardiolipin-cytochrome c interactions. Theoretically complementary mechanisms for mitochondrial support.
Nad-Precursors
CompatibleNAD+ precursors (NMN, NR) support different aspects of mitochondrial function than SS-31. Non-overlapping mechanisms may provide additive benefits.
Urolithin-A
CompatibleUrolithin A promotes mitophagy while SS-31 optimizes existing mitochondrial function. Different but potentially complementary approaches to mitochondrial health.
Idebenone
CompatibleIdebenone bypasses Complex I while SS-31 optimizes overall ETC efficiency through cardiolipin. May have additive effects in mitochondrial dysfunction.
Research Note: Interaction data is based on published literature, mechanistic understanding, and theoretical considerations. Most peptide combinations lack direct clinical study. This information is for educational purposes only and does not constitute medical advice. Always consult qualified healthcare providers.
References
Key Studies Cited
Full reference list available on request. All citations link to PubMed for verification.
Methodology Note
This dossier synthesizes available evidence from peer-reviewed literature, regulatory documents, and clinical trial registries. Evidence strength ratings follow a modified GRADE approach.
For complete methodology details, see our Methodology page.
Important Disclaimer
This dossier is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before making health decisions.
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