SS-31 (Elamipretide)
unknown riskAlso: Elamipretide · Bendavia · MTP-131 · Szeto-Schiller Peptide 31
SS-31 (elamipretide) is a mitochondria-targeted cardioprotective peptide that concentrates in the inner mitochondrial membrane. It has FDA Breakthrough Therapy designation for heart failure with reduced ejection fraction and completed Phase 3 trials.
Reported Benefits
Cardioprotection
Reduces ischemia-reperfusion injury and preserves cardiac function in multiple models.
Heart Failure
Phase 2 MMAD trial showed improved 6-minute walk test in HFrEF patients.
Mitochondrial Function
Restores cristae ultrastructure and electron transport chain efficiency.
Mechanism of Action
SS-31 concentrates ~1000-fold in the inner mitochondrial membrane by electrostatic interactions with cardiolipin. It stabilizes cardiolipin-cytochrome c interactions, maintains cristae structure, and reduces electron leak/ROS production at Complex I. This preserves ATP production efficiency and reduces oxidative stress.
Key Clinical Studies
Chatfield KC et al. (2019)
RCT · Phase 2 heart failure
Improved 6MWT and cardiac output trends
Daubert MA et al. (2017)
RCT · Phase 2 MMAD
Improved distance-saturation product in HFrEF
Overview
SS-31 (elamipretide) stands out among peptides in this database as having FDA Breakthrough Therapy designation — a formal acknowledgment of preliminary clinical evidence showing substantial improvement over available therapies. This regulatory milestone reflects genuine therapeutic promise.
Cardiolipin Mechanism
The unique mechanism of SS-31 centers on cardiolipin — a phospholipid exclusively found in the inner mitochondrial membrane that is critical for energy production efficiency. In aging, heart failure, and ischemia, cardiolipin oxidizes and degrades, impairing electron transport chain function. SS-31 stabilizes cardiolipin, restoring mitochondrial architecture and bioenergetics.
Phase 3 Trajectory
Following Phase 2 success in heart failure with reduced ejection fraction (HFrEF), Phase 3 TAZPOWER and SPEED trials were conducted. Results showed functional improvements but trial design and endpoint selection challenges have complicated the regulatory pathway. Development continues as of 2025.
Broader Mitochondrial Disease Application
Beyond heart failure, SS-31 has shown promise in Barth syndrome (a rare cardiolipin-related mitochondrial disease), age-related skeletal muscle weakness, and renal ischemia-reperfusion injury — suggesting broad utility wherever mitochondrial dysfunction is the underlying pathology.
Regulatory Status
Research OnlyPhase 3 trials conducted; FDA Breakthrough Therapy designation received but no approval yet as of 2025
Safety Profile
Side Effects
- •Injection site reactions
- •Nausea (mild)
Contraindications
- •No established contraindications for short-term use
Drug Interactions
- •None established
Primary Uses
Weekly Briefing
Regulatory updates + new study breakdowns.
For Practitioners
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