SS-31 (Elamipretide) — Research Reference

SS-31, also known as Elamipretide or by its chemical name D-Arg-dimethylTyr-Lys-Phe-NH₂, is a synthetic aromatic-cationic tetrapeptide designed to selectively concentrate in the inner mitochondrial membrane. It belongs to the Szeto-Schiller (SS) family of mitochondria-targeted peptides developed by Hazel Szeto and Peter Schiller. SS-31 is the most extensively researched member of this family and has advanced into clinical trials for cardiovascular and renal conditions.

Quick Reference

Overview

SS-31 was designed around a specific pharmacological insight: the alternating cationic and aromatic residues in its sequence give it a high affinity for cardiolipin — a phospholipid found almost exclusively in the inner mitochondrial membrane (IMM). Cardiolipin plays a critical structural role in organising the electron transport chain complexes and in maintaining membrane integrity.

Research has investigated SS-31 for its potential role in:

• Cardiolipin protection: Preventing cardiolipin peroxidation by reactive oxygen species (ROS), which is proposed to be a primary driver of mitochondrial dysfunction in ageing and disease
• Mitochondrial bioenergetics: Restoring ATP production in cells with impaired respiratory chain function — studied in models of ischaemia-reperfusion injury, heart failure, and ageing
• Cardiac function: Clinical trial data has reported improvements in cardiac energetics in patients with heart failure with preserved ejection fraction (HFpEF) — a condition with limited treatment options
• Renal protection: Studies in models of acute kidney injury have reported reduced cellular injury markers following SS-31 administration
• Neuroprotection: Animal research has investigated SS-31 for potential protection of neuronal mitochondria in models of neurodegeneration

SS-31 is not approved as a pharmaceutical in any major jurisdiction, though it has completed Phase 2 clinical trials (MMAD trial in HFpEF). It is classified as a research compound in most contexts.

Reported Protocols

The following information represents commonly reported research ranges drawn from anecdotal accounts and clinical trial data. These are not medical recommendations.

Subcutaneous Protocol

Subcutaneous injection is the most commonly reported route in research accounts. Clinical trials have used intravenous infusion; anecdotal research predominantly describes subcutaneous administration.

Commonly reported doses in anecdotal research contexts range from 1 mg to 10 mg per day:

• Low range: 1–2 mg per day, once daily subcutaneous injection
• Mid range: 5 mg per day
• Duration: Commonly reported research periods of 4–12 weeks

Clinical trial context: The MMAD trial (2020) used intravenous elamipretide 40 mg/day for 5 days in heart failure patients. Anecdotal subcutaneous research doses are substantially lower and cannot be directly compared to clinical trial protocols.

Reported Effects

The following effects have been reported in clinical research and anecdotal accounts. This list reflects the research landscape, not confirmed clinical outcomes.

Mitochondrial Function and Energetics

Published clinical trial data from the MMAD study reported statistically significant improvements in cardiac phosphocreatine-to-ATP ratios — a measure of cardiac energetics — in patients with heart failure with preserved ejection fraction (HFpEF) following elamipretide administration. This represents one of the more clinically concrete findings in SS-31 research.

Cardioprotection

Animal models of ischaemia-reperfusion injury have reported reductions in infarct size and improved cardiac function following SS-31 administration. The proposed mechanism involves prevention of cardiolipin oxidation, which research suggests is a critical step in ischaemia-induced cell death.

Renal Protection

Studies in models of contrast-induced nephropathy and acute kidney injury have reported reduced markers of tubular cell injury following SS-31 pre-treatment. This area has attracted pharmaceutical development interest.

Neuroprotection

Animal research has investigated SS-31 for potential mitochondrial protection in neuronal cells, including models of Alzheimer’s disease and Parkinson’s disease, with some studies reporting reduced oxidative stress markers and improved behavioural outcomes.

Exercise and Physical Performance

Animal research has reported improved exercise capacity and mitochondrial function in aged rodents following SS-31 administration. Anecdotal human research accounts describe improved energy levels and exercise recovery.

Reported Side Effects

Reported side effects in research and anecdotal accounts include the following. This list does not constitute a comprehensive safety profile.

SS-31 has been administered to human patients in clinical trials with a generally favourable reported tolerability profile at the doses studied. However, clinical trial doses were administered intravenously in medical settings. Subcutaneous research doses have a limited formal safety record. The compound has not been comprehensively evaluated in research compound contexts outside of clinical trials.

Storage & Handling

Lyophilized Powder (Unreconstituted)

• Room temperature: Reported stable for up to 3 months when kept away from light and moisture
• Refrigerator (2–8°C): Preferred for extended storage; protect from light
• Freezer: Acceptable for long-term storage; avoid repeated freeze-thaw cycles
• Light sensitivity: Store in an opaque or amber vial; the aromatic residues may be light-sensitive

Reconstituted Solution

• Refrigerator (2–8°C): Use within 4–6 weeks of reconstitution
• Do not freeze a reconstituted solution
• Bacteriostatic water or sterile saline are both reported as diluents
• Discard if the solution becomes cloudy, discoloured, or shows particulate matter

Reconstitution

Add the chosen diluent slowly along the inside wall of the vial. Swirl gently — do not shake. See the Reconstitution Guide for step-by-step instructions.

Frequently Asked Questions

What is cardiolipin and why does it matter? Cardiolipin is a phospholipid found almost exclusively in the inner mitochondrial membrane. It plays a structural role in organising the electron transport chain complexes and is essential for efficient ATP production. When cardiolipin is oxidised by reactive oxygen species — as occurs during ischaemia and in ageing — mitochondrial function deteriorates. SS-31’s high affinity for cardiolipin is the basis of its proposed cardioprotective mechanism.

Has SS-31 been tested in humans? Yes. SS-31 (as elamipretide) has been studied in multiple Phase 1 and Phase 2 clinical trials, including the MMAD trial in heart failure with preserved ejection fraction (HFpEF), trials in Barth syndrome (a cardiolipin biosynthesis disorder), and trials in primary mitochondrial myopathy. These trials have generally reported an acceptable tolerability profile and some evidence of target engagement.

How does SS-31 differ from MOTS-c or Epitalon? SS-31 targets the inner mitochondrial membrane directly via cardiolipin affinity and acts as an antioxidant at the site of mitochondrial ROS production. MOTS-c is a mitochondria-encoded signalling peptide that acts systemically to regulate metabolic pathways via AMPK. Epitalon targets the pineal gland and telomerase. The three compounds represent distinct mechanisms within the broad category of longevity-associated research compounds.

Is SS-31 the same as MTP-131? Yes. MTP-131 is a clinical development name for elamipretide (SS-31) used by Stealth BioTherapeutics. All three names — SS-31, elamipretide, and MTP-131 — refer to the same compound.

Related Pages

Goals: Longevity · Neuroprotection

Class: Mitochondrial Peptides

References & Further Reading

• Szeto HH. (2014). First-in-class cardiolipin-protective compound as a therapeutic agent to restore mitochondrial bioenergetics. British Journal of Pharmacology, 171(8), 2029–2050. PubMed →
• Birk AV, et al. (2013). The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin. Journal of the American Society of Nephrology, 24(8), 1250–1261. PubMed →
• Daubert MA, et al. (2017). Novel mitochondria-targeting peptide in heart failure treatment: a randomized, placebo-controlled trial of elamipretide. Circulation: Heart Failure, 10(12). PubMed →