SS-31

Moderate Evidence

What Is SS-31?

SS-31, also known as elamipretide (and previously as Bendavia or MTP-131), is a synthetic tetrapeptide that selectively targets the inner mitochondrial membrane. It was developed by Dr. Hazel Szeto and Dr. Peter Bhatt Schiller at Weill Cornell Medical College, and the “SS” designation stands for Szeto-Schiller [1].

What makes SS-31 unique among peptides is its specific mechanism: it binds to cardiolipin, a phospholipid found exclusively in the inner mitochondrial membrane that is essential for electron transport chain function and ATP production. Mitochondrial dysfunction is now recognised as a central feature of aging and many chronic diseases, making SS-31 one of the most scientifically significant peptides under active clinical investigation [2].

SS-31 is the closest to potential FDA approval of any peptide in the anti-aging category, with multiple Phase 2 and Phase 3 clinical trials completed or underway. However, it is not yet approved for any therapeutic indication.

Mechanism of Action

Cardiolipin binding. SS-31 concentrates in the inner mitochondrial membrane at over 1,000-fold its extracellular concentration. It binds to cardiolipin, stabilising the interaction between cardiolipin and cytochrome c — a critical step in the electron transport chain. This stabilisation improves electron transfer efficiency and reduces electron leak, which in turn reduces the production of reactive oxygen species (ROS) [3].

Mitochondrial bioenergetics. By improving electron transport chain efficiency, SS-31 may enhance ATP production — the cell’s primary energy currency. Studies have shown increased ATP synthesis in cells treated with SS-31, particularly under conditions of oxidative stress or mitochondrial dysfunction [4].

ROS reduction without antioxidant scavenging. Unlike traditional antioxidants that scavenge free radicals after they are produced, SS-31 reduces ROS production at the source by improving electron transport chain coupling. This is considered a more effective approach to oxidative stress than conventional antioxidant supplementation [2].

Mitochondrial dynamics. Research suggests SS-31 may influence mitochondrial fission and fusion dynamics, potentially promoting a healthier mitochondrial network within cells [5].

Research and Evidence

Barth Syndrome (TAZPOWER Trial)

The most advanced clinical evidence for SS-31 comes from the TAZPOWER trial in Barth syndrome, a rare genetic mitochondrial disorder caused by mutations in the tafazzin gene that result in abnormal cardiolipin. The randomised, placebo-controlled Phase 3 trial showed trends toward improvement in six-minute walk distance and cardiac function, with more significant improvements observed during the open-label extension period [6].

Heart Failure

SS-31 has been studied in Phase 2 trials for heart failure with reduced ejection fraction (HFrEF). The rationale is that mitochondrial dysfunction in cardiac muscle is a key contributor to heart failure progression. Early trial data showed improvements in left ventricular volumes and cardiac output in treated patients [7].

Primary Mitochondrial Myopathy

Clinical trials in patients with primary mitochondrial myopathy (PMM) have evaluated SS-31’s ability to improve exercise tolerance and muscle function. These trials have provided additional human data on the peptide’s safety and tolerability profile.

Age-Related Conditions

Preclinical research has explored SS-31 for age-related macular degeneration, renal injury, and skeletal muscle aging. Animal studies have shown that SS-31 can reverse age-related mitochondrial dysfunction in skeletal muscle, restoring bioenergetic capacity to more youthful levels [8].

Exercise Recovery

Animal studies suggest SS-31 may reduce exercise-induced oxidative damage and accelerate recovery of muscle function following strenuous exercise. The proposed mechanism is improved mitochondrial resilience under metabolic stress [9].

Dosage and Administration

Important: SS-31/elamipretide dosing in clinical trials has been standardised under controlled conditions. The following reflects reported trial doses and community protocols. Always consult a qualified healthcare provider.

Clinical Trial Doses

• Barth syndrome trials: 40 mg subcutaneous injection daily
• Heart failure trials: 4 mg/hour intravenous infusion (acute) or 40 mg subcutaneous daily (chronic)

Community-Referenced Protocols

• Subcutaneous: 5-50 mg per day (wide variation reported)
• Research-grade SS-31 dosing lacks standardisation outside clinical trials

Side Effects and Safety

SS-31 has a favourable safety profile in completed clinical trials:

Reported in clinical trials:

• Injection site reactions (most common — mild, transient)
• Headache
• Nausea (mild)
• Dizziness (uncommon)

Safety signals:

• No serious adverse events attributed to SS-31 in completed trials
• Well-tolerated at doses up to 40 mg daily in multi-month studies
• No significant effects on standard laboratory parameters (liver, kidney, haematological)
• Long-term safety data continues to accumulate through ongoing trials

Unknowns:

• Multi-year safety data is still limited
• Effects in pregnancy are unstudied
• Interactions with other mitochondrial-targeting compounds have not been characterised

Frequently Asked Questions

How is SS-31 different from other anti-aging peptides?

SS-31 is unique in that it targets mitochondrial function directly by binding to cardiolipin in the inner mitochondrial membrane. Other anti-aging peptides like Epitalon target telomeres, and GHK-Cu targets gene expression and collagen. SS-31 addresses what many researchers consider the most fundamental driver of aging — mitochondrial dysfunction.

Is SS-31 close to FDA approval?

SS-31 (as elamipretide) is further along in the FDA approval process than almost any other research peptide. It has completed Phase 2 and Phase 3 trials. However, FDA approval depends on trial outcomes meeting regulatory thresholds, and the timeline remains uncertain.

Can SS-31 improve exercise performance?

Animal research suggests SS-31 may improve mitochondrial resilience during exercise and accelerate recovery. However, it is not classified as a performance-enhancing peptide in the traditional sense — it supports cellular energy production rather than directly enhancing strength or endurance.

Is SS-31 the same as elamipretide?

Yes. SS-31, elamipretide, Bendavia, and MTP-131 all refer to the same peptide. “SS-31” is the research designation, while “elamipretide” is the pharmaceutical name used in clinical trials.

References

References

1. Szeto HH. First-in-class cardiolipin-protective compound as a therapeutic agent to restore mitochondrial bioenergetics. British Journal of Pharmacology. 2014;171(8):2029-2050.
2. Szeto HH, Birk AV. Serendipity and the discovery of novel compounds that restore mitochondrial plasticity. Clinical Pharmacology & Therapeutics. 2014;96(6):672-683.
3. 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;24(8):1250-1261.
4. Siegel MP, et al. Mitochondrial-targeted peptide rapidly improves mitochondrial energetics and skeletal muscle performance in aged mice. Aging Cell. 2013;12(5):763-771.
5. Campbell MD, et al. Improving mitochondrial function with SS-31 reverses age-related redox stress and improves exercise tolerance in aged mice. Free Radical Biology and Medicine. 2019;134:268-281.
6. Reid Thompson W, et al. A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome. Genetics in Medicine. 2021;23(3):471-478.
7. Butler J, et al. Effects of elamipretide on left ventricular function in patients with heart failure with reduced ejection fraction: the PROGRESS-HF phase 2 trial. Journal of Cardiac Failure. 2020;26(5):429-437.
8. Siegel MP, et al. Mitochondrial-targeted peptide rapidly improves mitochondrial energetics and skeletal muscle performance in aged mice. Aging Cell. 2013;12(5):763-771.
9. Min K, et al. Mitochondrial-targeted antioxidants protect skeletal muscle against immobilization-induced muscle atrophy. Journal of Applied Physiology. 2011;111(5):1459-1466.

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