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SS-31

Szeto-Schiller peptide · mitochondria-targeted
What it is

SS-31 (elamipretide) is a short, mitochondria-targeted peptide that binds cardiolipin on the inner mitochondrial membrane and supports the machinery that makes cellular energy.[1]

Origin: Developed as one of the Szeto-Schiller (SS) peptides; a 2014 review by Hazel H. Szeto describes SS-31 as a first-in-class cardiolipin-protective compound aimed at restoring mitochondrial bioenergetics.[1]

What researchers study it for

Research areas

Elamipretide has been tested in people for rare mitochondrial disease and for other conditions where mitochondria struggle.[2][3][4][5]

  • Binding cardiolipin on the inner mitochondrial membrane and supporting oxidative phosphorylation in lab and animal models[1]
  • Improving knee-extensor muscle strength in Barth syndrome, the basis for accelerated FDA approval of Forzinity (elamipretide)[2][3]
  • Primary mitochondrial myopathy in a large controlled trial that did not meet its primary endpoints[4]
  • Heart failure with reduced ejection fraction in a phase 2 trial that did not improve the primary heart-size measure[5]
  • A single-dose study in older adults looking at muscle mitochondrial ATP production[6]

Evidence level

Level 4 of 4: Large human trialsElamipretide (Forzinity) received accelerated FDA approval for Barth syndrome based on clinical data in that rare disease; other large trials outside that use have had mixed primary results.[2][4][5]

Why so few human trials?

Cautions

Studies and regulators point to several reasons for care.

  • Forzinity is approved under accelerated approval for Barth syndrome in patients weighing at least 30 kg, and FDA is requiring a confirmatory trial to show the muscle-strength change predicts real patient benefit[2]
  • The most common side effects in Forzinity trials were mild-to-moderate injection site reactions; serious reactions have also been reported[2][3]
  • Large trials in primary mitochondrial myopathy and in heart failure with reduced ejection fraction did not meet their primary endpoints[4][5]
  • Research SS-31 is the same peptide backbone as elamipretide, but research vials are not the FDA-approved Forzinity drug product[2][3]

Also called

SS-31 goes by several names.

  • Elamipretide, the generic (USAN) name[2][3]
  • Forzinity, the brand name of the FDA-approved elamipretide injection for Barth syndrome[2][3]
  • Szeto-Schiller peptide SS-31[1]

Often stacked with

MOTS-c. SS-31 and MOTS-c are paired because they work on mitochondria, the cell’s energy makers, in two different ways: SS-31 protects the inner membrane where energy is made, and MOTS-c is a messenger that mitochondria send out to the rest of the cell.[1][7][8]

MOTS-cTogether:StackMOTS-c →

Good to know

Forzinity is given as a subcutaneous injection under the skin; that approved product is not the same as a research SS-31 vial.[2][3]

Handling

Storage basics General

These general basics apply to most freeze-dried research peptides.

Most research peptides come as a freeze-dried powder in a sealed vial
Unmixed vials are generally kept cold, dry, and away from light
Mixed solutions are generally refrigerated, since they are less stable than the dry powder
Peptides 101For mixing basicsNPL Dose CalculatorTo work out concentration after mixing
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Sources and studies

These studies and official pages are the research behind this profile.