What Is SS-31 (Elamipretide / MTP-131)? A Research Guide

SS-31, also known as elamipretide (and formerly MTP-131), is a synthetic mitochondria-targeting tetrapeptide that selectively binds cardiolipin on the inner mitochondrial membrane. It is studied in preclinical and clinical research focused on mitochondrial bioenergetics, oxidative stress, and cellular energy production. This article is educational only. Any research material referenced here is intended for research use only (RUO) and is not for human consumption, diagnosis, or treatment.

Quick facts

• Class: Szeto–Schiller (SS) mitochondria-targeted tetrapeptide
• Other names: elamipretide, MTP-131 (formerly Bendavia)
• Sequence studied in the literature: D-Arg-Dmt-Lys-Phe-NH₂
• Molecular target: cardiolipin, a phospholipid of the inner mitochondrial membrane
• Research focus: mitochondrial bioenergetics, electron transport, and reactive oxygen species

What is SS-31?

SS-31 is a member of the Szeto–Schiller family of small, cell-permeable peptides developed to concentrate within mitochondria. In the research literature it is described as a synthetic tetrapeptide whose alternating aromatic and basic residues give it a net positive charge. This charge profile drives electrostatic attraction to negatively charged cardiolipin, allowing the peptide to accumulate at the inner mitochondrial membrane — the site of oxidative phosphorylation. In a clinical-research context the same molecule is referred to as elamipretide. The discussion below summarizes published findings; it does not describe outcomes for any reader.

What does the research show?

Published work on SS-31/elamipretide spans cell-culture systems, animal models, and human clinical trials. In a randomized, double-blind, placebo-controlled dose-escalation trial in adults with genetically confirmed primary mitochondrial myopathy (the MMPOWER study), investigators evaluated the safety, tolerability, and exercise-performance effects of intravenous elamipretide (Karaa et al., 2018). In preclinical work, an eight-week study in aged mice reported that SS-31 treatment restored maximal mitochondrial ATP production and shifted muscle redox balance toward a more reduced state, alongside improved fatigue resistance, without increasing total mitochondrial content (Campbell et al., 2019). A 2025 review summarizes how these and related findings position cardiolipin binding as the unifying mechanism across diverse experimental models (Tung et al., 2025). These are research findings reported in the scientific literature, not claims about effects in any reader.

Mechanisms studied in the lab

• Cardiolipin binding: SS-31 binds cardiolipin in the inner mitochondrial membrane, studied for effects on membrane organization and cristae structure.
• Electron transport and ATP: the literature describes enhanced assembly and stability of respiratory complexes (I, III, IV) and more efficient electron transfer, studied as a route to improved ATP synthesis.
• Reactive oxygen species (ROS): by reducing electron leakage along the electron transport chain, SS-31 is studied for its effect on mitochondrial ROS production and oxidative stress markers.

Research status

Elamipretide is an investigational compound evaluated across multiple clinical trials for primary mitochondrial conditions. In 2025 the U.S. FDA approved elamipretide (brand name Forzinity, Stealth BioTherapeutics) for the specific indication of Barth syndrome; this narrow approval applies only to that finished prescription drug and that patient population. It does not make research-grade SS-31 a finished, approved, or human-use product for any other purpose. Any SS-31 sold as a research chemical is supplied strictly for laboratory research use only — not a dietary supplement, not a compounded medication, and not intended to diagnose, treat, cure, or prevent any disease.

Related research peptides

If you study mitochondrial metabolism and cellular energy pathways, explore the full research peptide catalog, and read our educational articles on MOTS-c, a mitochondrial-derived peptide studied in metabolic research, and NAD+, a coenzyme central to mitochondrial energy metabolism.

FAQ

Is SS-31 the same as elamipretide? Yes. SS-31, elamipretide, and the former code name MTP-131 refer to the same mitochondria-targeted tetrapeptide. “SS-31” is most common in laboratory literature, while “elamipretide” is the name used in clinical development.

How does SS-31 target mitochondria? In published research, its positively charged residues are attracted to cardiolipin, a phospholipid concentrated in the inner mitochondrial membrane, which drives its accumulation within mitochondria.

Is research-grade SS-31 approved for human use? No. Although elamipretide received a narrow FDA approval for Barth syndrome as a finished prescription drug, research-grade SS-31 is supplied for research use only and is not for human consumption.

References

1. Tung C, et al. Elamipretide: A Review of Its Structure, Mechanism of Action, and Therapeutic Potential. Int J Mol Sci. 2025.
2. Karaa A, et al. Randomized dose-escalation trial of elamipretide in primary mitochondrial myopathy (MMPOWER). Neurology. 2018.
3. Campbell MD, et al. Improving mitochondrial function with SS-31 in aged mice. Free Radic Biol Med. 2019.

For research use only. Not for human or veterinary consumption. The narrow FDA approval of elamipretide (Forzinity) for Barth syndrome applies only to that finished prescription drug, not to research-grade materials. Statements have not been evaluated by the FDA.