What is Elamipretide (SS-31)?

A mitochondria-targeting peptide that stabilizes cardiolipin — newly approved. Structurally it is Synthetic mitochondria-targeting tetrapeptide (Szeto-Schiller).

How strong is the evidence for SS-31?

PeptideHormone grades SS-31 at the "Clinical" evidence tier — it is supported by human clinical trials, though still maturing or narrower in scope. It is catalogued as a community research peptide outside the approved-drug system, and the tier is an editorial judgment about the public literature that can change as the science does.

What is the half-life of SS-31?

The reported circulating half-life of SS-31 is ~4 h (subcutaneous).

ElamipretideSS-31

A mitochondria-targeting peptide that stabilizes cardiolipin — newly approved.

Research peptideClinical

Aimed at a membrane lipid rather than a receptor — a different way to address a cell, and now an approved one.

Identity

Class: Synthetic mitochondria-targeting tetrapeptide (Szeto-Schiller)
Source: Synthetic; not derived from an endogenous hormone
Receptor: No cell-surface receptor; binds cardiolipin in the inner mitochondrial membrane

Key properties

Evidence floorClinicalREF1CLIN1

Molecular weight

~639.8 Da

REF

Half-life (native)

~4 h (subcutaneous)

CLIN

Model dosing

Approximate values for the native hormone; engineered analogs are often deliberately larger and far longer-acting. Each figure carries its own provenance tier, and the floor is the weakest of them - the Standard.

Mechanism

SS-31 concentrates in the inner mitochondrial membrane and binds cardiolipin, helping preserve cristae structure and electron-transport efficiency while reducing reactive oxygen species. Because it protects mitochondrial energetics rather than acting on a surface receptor, it is studied wherever mitochondrial dysfunction is central — cardiomyopathy, mitochondrial myopathy, and neurodegeneration.

Reference notes

As elamipretide, it received its first regulatory approval in 2026 — for the rare mitochondrial disease Barth syndrome — after roughly a decade of clinical development.
Its molecular target is cardiolipin, a lipid unique to the inner mitochondrial membrane, rather than a classical receptor.
It is sold in the research-peptide market as 'SS-31', though the underlying molecule now also exists in an approved, trial-backed form.

Common questions

What is Elamipretide (SS-31)?: A mitochondria-targeting peptide that stabilizes cardiolipin — newly approved. Structurally it is Synthetic mitochondria-targeting tetrapeptide (Szeto-Schiller).
How does SS-31 work?: SS-31 concentrates in the inner mitochondrial membrane and binds cardiolipin, helping preserve cristae structure and electron-transport efficiency while reducing reactive oxygen species. Because it protects mitochondrial energetics rather than acting on a surface receptor, it is studied wherever mitochondrial dysfunction is central — cardiomyopathy, mitochondrial myopathy, and neurodegeneration.
How strong is the evidence for SS-31?: PeptideHormone grades SS-31 at the "Clinical" evidence tier — it is supported by human clinical trials, though still maturing or narrower in scope. It is catalogued as a community research peptide outside the approved-drug system, and the tier is an editorial judgment about the public literature that can change as the science does.
What is the half-life of SS-31?: The reported circulating half-life of SS-31 is ~4 h (subcutaneous).

Selected literature

Curated peer-reviewed reviews, sourced from PubMed. Selected for relevance, not exhaustive — open any entry on PubMed for the full record and its primary citations.

1.Elamipretide: A Review of Its Structure, Mechanism of Action, and Therapeutic Potential · International journal of molecular sciences, 2025 · PMID 39940712
2.Elamipretide: First Approval · Drugs, 2026 · PMID 41335372
3.Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial · Neurology, 2023 · PMID 37268435

External references

SS-31 in the public knowledge graph — the same entity resolved across the authoritative chemistry and protein databases.