Ordering from the Americas?Switch to the US store
We don't ship to your country yet. We ship across Europe and the Americas. You can keep browsing.
Account

Peptency Academy · Compound

SS-31 (elamipretide tetrapeptide)

SS-31, also named elamipretide (its INN) and MTP-131, is the synthetic tetrapeptide D-Arg-Dmt-Lys-Phe-NH2, in which Dmt is 2,6-dimethyl-L-tyrosine. Source sentencePubChem CID 11764719: Title Elamipretide; synonyms include Elamipretide [USAN:INN], MTP-131, SS-31, D-Arg-Dmt-Lys-Phe-NH2, D-Arginyl-2,6-dimethyl-L-tyrosyl-L-lysyl-L-phenylalaninamide. PMID 32554501 abstract: "The synthetic tetrapeptide, elamipretide (SS-31)"1 PubChem CID 117647192 Proc Natl Acad Sci U S A 2020 PubChem records it under CID 11764719: formula C32H49N9O5, average mass about 639.8 Da, CAS 736992-21-5. Source sentenceCID 11764719: Title Elamipretide; MolecularFormula C32H49N9O5; MolecularWeight 639.8; MonoisotopicMass 639.38566570; InChIKey SFVLTCAESLKEHH-WKAQUBQDSA-N; synonyms include 736992-21-5, MTP-131, SS-31, SS31, Elamipretide [USAN:INN], D-Arg-Dmt-Lys-Phe-NH21 PubChem CID 11764719 Laboratory studies at Weill Cornell Medical College measured its binding to cardiolipin, an anionic phospholipid of the inner mitochondrial membrane (2013 and 2014). Source sentencePMID 23813215 abstract: "we used a polarity-sensitive fluorescent analog of SS-31 [...] cardiolipin, an anionic phospholipid expressed on the inner mitochondrial membrane"; affiliation: Departments of Pharmacology, Weill Cornell Medical College, New York. PMID 24134698: "Interactions of SS-31 with cardiolipin were studied using liposomes and bicelles"3 J Am Soc Nephrol 20134 Br J Pharmacol 2014 PubMed held 451 records with SS-31, elamipretide or MTP-131 in the title or abstract on 25 Oct 2026, 93 of them tagged as reviews. Source sentenceesearch ("SS-31"[tiab] OR elamipretide[tiab] OR "MTP-131"[tiab]): count 451; AND review[pt]: count 93 (25 Oct 2026)5 PubMed search for SS-31, elamipretide or MTP-131, 25 October 20266 PubMed search for reviews of SS-31, 25 October 2026

Version 1Edited Evidence through 25 sources

Regulatory content shown for: EU and UK.

Tetrapeptide

  • Elamipretide, PubChem CID 11764719SS-314 residuesabout 639.8 DaSource sentenceCID 11764719: Title Elamipretide; MolecularFormula C32H49N9O5; MolecularWeight 639.8; MonoisotopicMass 639.38566570; InChIKey SFVLTCAESLKEHH-WKAQUBQDSA-N; synonyms include 736992-21-5, MTP-131, SS-31, SS31, Elamipretide [USAN:INN], D-Arg-Dmt-Lys-Phe-NH21 PubChem CID 11764719

Known, not known, contested

Known

  • A 2014 study measured SS-31 interactions with liposomes and bicelles made of phosphatidylcholine alone or with cardiolipin, by fluorescence spectroscopy, turbidity and NMR. Source sentenceEXPERIMENTAL APPROACH: "Interactions of SS-31 with cardiolipin were studied using liposomes and bicelles containing phosphatidylcholine alone or with cardiolipin. Structural interactions were assessed by fluorescence spectroscopy, turbidity and nuclear magnetic resonance."4 Br J Pharmacol 2014
  • A 2020 study mapped SS-31 protein contacts in mitochondria by chemical cross-linking with mass spectrometry, including the cross-linked residues. Source sentenceAbstract: "Here we utilize chemical cross-linking with mass spectrometry to identify protein interactors of SS-31 in mitochondria. [...] Residues cross-linked with SS-31 [...]"2 Proc Natl Acad Sci U S A 2020
  • A 2022 study modelled the membrane-bound conformations of SS-31 and three tetrapeptide analogues by NMR and molecular dynamics. Source sentenceAbstract: "[...] structural models for this class of compounds, obtained with Nuclear Magnetic Resonance (NMR) and molecular dynamics approaches [...] in the membrane-bound state"7 eLife 2022
  • Two randomised trials with published primary results did not meet their primary endpoints: MMPOWER-3 (phase 3, 218 participants with primary mitochondrial myopathy, 2023) and the randomised part of a 12 subject crossover trial in Barth syndrome (2021). Source sentencePMID 37268435: "a pivotal, phase-3, randomized, double-blind, placebo-controlled clinical trial"; "Participants (N = 218) were randomized"; "The study did not meet its primary endpoints". PMID 33077895: "In part 1, 12 subjects were randomized [...]"; "In part 1 neither primary endpoint was met."8 Neurology 20239 Genet Med 2021
  • ClinicalTrials.gov listed 21 records with elamipretide as an intervention on 25 Oct 2026; Stealth BioTherapeutics is lead sponsor of 19 of them. Source sentencequery.intr elamipretide: countTotal 21 (query.term 21); query.lead "Stealth BioTherapeutics": 19 (25 Oct 2026)10 ClinicalTrials.gov search, 25 October 2026

Not known

  • A randomised, placebo controlled phase 4 trial in Barth syndrome (NCT07531251) has been recruiting since 2 Jul 2026; its estimated primary completion is 30 Sep 2029. Source sentenceNCT07531251: overallStatus RECRUITING; phases PHASE4; allocation RANDOMIZED; brief summary "randomized, double-blind, parallel-group, placebo-controlled clinical trial"; startDate 2026-07-02 (ACTUAL); primaryCompletionDate 2029-09-30 (ESTIMATED)11 ClinicalTrials.gov NCT07531251
  • No results were posted on 25 Oct 2026 for the completed phase 3 trial in primary mitochondrial disease from nuclear DNA mutations (NCT05162768, completed 4 Dec 2024). Source sentenceNCT05162768: overallStatus COMPLETED; phases PHASE3; completionDate 2024-12-04 (ACTUAL); hasResults false (25 Oct 2026)12 ClinicalTrials.gov NCT05162768
  • The authors of the 2020 cross-linking study state that mechanistic details of SS-31's pharmacological effects are unknown. Source sentenceAbstract: "[...] mechanistic details of its pharmacological effects are unknown."2 Proc Natl Acad Sci U S A 2020

Contested

Nothing listed yet.

Chemistry: SS-31 as PubChem CID 11764719 records it

Sequence
D-Arg-Dmt-Lys-Phe-NH2
Length
4 residues
Modifications
D-arginine at position 1, 2,6-dimethyl-L-tyrosine (Dmt) at position 2, C-terminal amide
Formula
C32H49N9O5
Monoisotopic mass
639.3857 Da
Average mass
639.8 Da
CAS
736992-21-5
PubChem CID
11764719
InChIKey
SFVLTCAESLKEHH-WKAQUBQDSA-N
Synonyms
elamipretide, MTP-131, SS31, RX-31, Szeto-schiller peptide
Salt form
No salt form stated in the record
Checked 25 October 2026 1 PubChem CID 11764719

Chemistry: the four residues and the identifiers

  • PubChem's systematic name lists four units in order: D-arginyl, 2,6-dimethyl-L-tyrosyl, L-lysyl and L-phenylalaninamide. The chain starts with a D-amino acid, carries the non-standard residue 2,6-dimethyl-L-tyrosine at position 2 and ends in a C-terminal amide. Source sentenceSynonym (systematic name): D-Arginyl-2,6-dimethyl-L-tyrosyl-L-lysyl-L-phenylalaninamide; L-Phenylalaninamide, D-arginyl-2,6-dimethyl-L-tyrosyl-L-lysyl-; IUPAC name begins (2S)-6-amino-2-[[(2S)-2-[[(2R)-2-amino-5-(diaminomethylideneamino)pentanoyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)propanoyl]amino]1 PubChem CID 11764719
  • A 2014 study writes the sequence as D-Arg-dimethylTyr-Lys-Phe-NH2. Source sentenceBACKGROUND AND PURPOSE: "SS-31 (D-Arg-dimethylTyr-Lys-Phe-NH2 )"4 Br J Pharmacol 2014
  • PubChem gives a monoisotopic mass of 639.3857 Da and the InChIKey SFVLTCAESLKEHH-WKAQUBQDSA-N, and lists the name as Elamipretide [USAN:INN]. Source sentenceCID 11764719: Title Elamipretide; MolecularFormula C32H49N9O5; MolecularWeight 639.8; MonoisotopicMass 639.38566570; InChIKey SFVLTCAESLKEHH-WKAQUBQDSA-N; synonyms include 736992-21-5, MTP-131, SS-31, SS31, Elamipretide [USAN:INN], D-Arg-Dmt-Lys-Phe-NH21 PubChem CID 11764719
  • PubChem's 62 synonyms for CID 11764719 include MTP-131, SS-31, SS31, RX-31 and Szeto-schiller peptide; none is written MTP-31 or MTP 31 (read on 25 Oct 2026). Source sentencePUG REST synonyms for CID 11764719, 62 entries: Elamipretide, 736992-21-5, MTP-131, MTP 131, SS-31, Szeto-schiller peptide, MTP131, RX 31, SS 31, RX-31, SS31, ...; no entry MTP-31 or MTP 31 (25 Oct 2026)1 PubChem CID 11764719

Which molecule does an SS-31 certificate describe?

  • Read the formula and mass on the certificate of analysis. SS-31 is C32H49N9O5, average mass about 639.8 Da, monoisotopic mass 639.3857 Da (PubChem CID 11764719). SS-20 (Phe-D-Arg-Phe-Lys-NH2, also coded SBT-020, PubChem CID 10008657) is a different tetrapeptide without dimethyltyrosine: C30H45N9O4, about 595.7 Da. Source sentenceCID 11764719: MolecularFormula C32H49N9O5, MolecularWeight 639.8, MonoisotopicMass 639.38566570; CID 10008657: Title L-Lysinamide, L-phenylalanyl-D-arginyl-L-phenylalanyl-; synonyms SS-20, SBT-020; MolecularFormula C30H45N9O4; MolecularWeight 595.71 PubChem CID 1176471913 PubChem CID 10008657
  • MOTS-c (mitochondrial open reading frame of the 12S rRNA-c) is a different molecule: PubChem CID 146675088, C101H152N28O22S2, about 2174.6 Da. Source sentenceCID 146675088: Title Mots-c; MolecularFormula C101H152N28O22S2; MolecularWeight 2174.6. WADA 2026 list S4.4.1: "mitochondrial open reading frame of the 12S rRNA-c (MOTS-c)"14 PubChem CID 14667508815 WADA Prohibited List 2026 (Internet Archive capture of 1 October 2025)
  • A 2022 structure and activity study compared SS-31 with three tetrapeptide analogues that differ in aromatic side chain composition and sequence register. Source sentenceAbstract: "we conducted a quantitative structure-activity analysis of three alternative tetrapeptide analogs, benchmarked against SS-31, that differ with respect to aromatic side chain composition and sequence register"7 eLife 2022

What is SS-31?

SS-31 is elamipretide: the synthetic tetrapeptide D-Arg-Dmt-Lys-Phe-NH2, where Dmt is 2,6-dimethyl-L-tyrosine (PubChem CID 11764719, CAS 736992-21-5, about 639.8 Da). Laboratory studies measured its binding to cardiolipin in the inner mitochondrial membrane. Source sentenceCID 11764719: Title Elamipretide; MolecularFormula C32H49N9O5; MolecularWeight 639.8; MonoisotopicMass 639.38566570; InChIKey SFVLTCAESLKEHH-WKAQUBQDSA-N; synonyms include 736992-21-5, MTP-131, SS-31, SS31, Elamipretide [USAN:INN], D-Arg-Dmt-Lys-Phe-NH2. PMID 23813215: "a polarity-sensitive fluorescent analog of SS-31 [...] cardiolipin, an anionic phospholipid expressed on the inner mitochondrial membrane"1 PubChem CID 117647193 J Am Soc Nephrol 2013

Is SS-31 the same as elamipretide?

Yes. PubChem CID 11764719 is titled Elamipretide, gives the name as Elamipretide [USAN:INN] and lists SS-31, SS31 and MTP-131 as synonyms; a 2020 paper writes "elamipretide (SS-31)". PubChem lists no name MTP 31: the development code is MTP-131. Source sentenceCID 11764719: Title Elamipretide; MolecularFormula C32H49N9O5; MolecularWeight 639.8; MonoisotopicMass 639.38566570; InChIKey SFVLTCAESLKEHH-WKAQUBQDSA-N; synonyms include 736992-21-5, MTP-131, SS-31, SS31, Elamipretide [USAN:INN], D-Arg-Dmt-Lys-Phe-NH2. No synonym MTP-31 or MTP 31 among the 62 entries (25 Oct 2026). PMID 32554501: "The synthetic tetrapeptide, elamipretide (SS-31)"1 PubChem CID 117647192 Proc Natl Acad Sci U S A 2020

Is SS-31 a peptide?

Yes. PubChem's systematic name for SS-31 lists four amino acid units (D-arginyl, 2,6-dimethyl-L-tyrosyl, L-lysyl and L-phenylalaninamide), and a 2014 study writes it as D-Arg-dimethylTyr-Lys-Phe-NH2. Source sentenceSynonym (systematic name): D-Arginyl-2,6-dimethyl-L-tyrosyl-L-lysyl-L-phenylalaninamide. PMID 24134698: "SS-31 (D-Arg-dimethylTyr-Lys-Phe-NH2 )"1 PubChem CID 117647194 Br J Pharmacol 2014

What is the molecular weight of SS-31?

PubChem gives an average mass of about 639.8 Da and a monoisotopic mass of 639.3857 Da for C32H49N9O5 (CID 11764719). Source sentenceCID 11764719: Title Elamipretide; MolecularFormula C32H49N9O5; MolecularWeight 639.8; MonoisotopicMass 639.38566570; InChIKey SFVLTCAESLKEHH-WKAQUBQDSA-N; synonyms include 736992-21-5, MTP-131, SS-31, SS31, Elamipretide [USAN:INN], D-Arg-Dmt-Lys-Phe-NH21 PubChem CID 11764719

What has research measured about SS-31 and cardiolipin?

Studies measured SS-31 binding to cardiolipin with a fluorescent analogue (2013), its interaction with cardiolipin-containing liposomes and bicelles by fluorescence, turbidity and NMR (2014), its protein contacts in mitochondria by cross-linking mass spectrometry (2020) and cristae structure in a rat heart ischemia reperfusion model by electron microscopy (2020). Source sentencePMID 23813215: "we used a polarity-sensitive fluorescent analog of SS-31 [...] cardiolipin"; PMID 24134698: "Interactions of SS-31 with cardiolipin were studied using liposomes and bicelles [...] Structural interactions were assessed by fluorescence spectroscopy, turbidity and nuclear magnetic resonance"; PMID 32554501: "chemical cross-linking with mass spectrometry to identify protein interactors of SS-31 in mitochondria"; PMID 32680996: "Serial block face scanning electron microscopy used to create 3D reconstructions of cristae ultrastructure", "rat cardiac ischemia-reperfusion"3 J Am Soc Nephrol 20134 Br J Pharmacol 20142 Proc Natl Acad Sci U S A 202016 Commun Biol 2020

Are there registered clinical trials of SS-31?

Yes. ClinicalTrials.gov listed 21 records with elamipretide as an intervention on 25 Oct 2026: 14 completed, 3 terminated, 2 recruiting, 1 active and not recruiting and 1 expanded access record; 14 have posted results. Stealth BioTherapeutics is lead sponsor of 19. Four records are listed under Registered trials. Source sentencequery.intr elamipretide: countTotal 21; filter.overallStatus COMPLETED 14, TERMINATED 3, RECRUITING 2, ACTIVE_NOT_RECRUITING 1, NOT_YET_RECRUITING 0, WITHDRAWN 0; NCT04689360 status AVAILABLE (expanded access); aggFilters results:with 14; query.lead "Stealth BioTherapeutics" 19 (25 Oct 2026)10 ClinicalTrials.gov search, 25 October 202617 ClinicalTrials.gov NCT0332374918 ClinicalTrials.gov NCT0309879712 ClinicalTrials.gov NCT0516276811 ClinicalTrials.gov NCT07531251

Is SS-31 authorised in the EU or the UK?

EU

No EU authorised medicine for elamipretide was found in EMA medicines data on 25 Oct 2026, and EMA's orphan designation data hold two positive designations for it. For the UK, a GOV.UK search for elamipretide returned no result on 25 Oct 2026; the MHRA products database was not checked. Source sentenceEMA medicines JSON (2,754 records, timestamp 2026-10-24): no record matching elamipretide, SS-31 or MTP-131. EMA orphan designations JSON (3,310 records): 2 records with active_substance elamipretide, status Positive. GOV.UK search q=elamipretide: total 0 (25 Oct 2026)19 EMA medicines data, 25 October 202620 EMA orphan designation data, 25 October 202621 GOV.UK search for elamipretide, 25 October 2026

Evidence map: SS-31

Primary studies of SS-31 (elamipretide), by model and by what was measured. Reviews are not counted. An empty cell means: not mapped yet.
ModelChemistry and analyticalPharmacokineticsReceptor binding and signallingTissue histologyBiomarkersClinical endpoint
Analytical only (no biological model)Chemistry and analytical1Not mapped yetNot mapped yetNot mapped yetNot mapped yetNot mapped yet
In vitro or ex vivoChemistry and analytical3Not mapped yetNot mapped yetNot mapped yetBiomarkers2Not mapped yet
RodentNot mapped yetNot mapped yetNot mapped yetTissue histology2Biomarkers1Not mapped yet
Other animalNot mapped yetNot mapped yetNot mapped yetNot mapped yetNot mapped yetNot mapped yetNot mapped yet
Human, uncontrolledNot mapped yetNot mapped yetNot mapped yetNot mapped yetBiomarkers1Clinical endpoint1
Human, randomisedNot mapped yetNot mapped yetNot mapped yetNot mapped yetBiomarkers2Clinical endpoint3

10 studies countedEvidence level facet: L4. A design scale, not a measure of strength or quality.

Counts only the ten exact match studies reviewed for this page on 25 October 2026, out of 451 PubMed records with SS-31, elamipretide or MTP-131 in the title or abstract (some of them unrelated to the peptide, see Integrity notes). Empty cells are not mapped yet; reviews are never counted.

Who produced this evidence

  • The 2013 and 2014 cardiolipin studies come from Weill Cornell Medical College in New York, with Szeto HH as last author and NIH extramural research support listed in PubMed. Source sentencePMID 23813215 affiliation: Departments of Pharmacology, Weill Cornell Medical College, New York; last author Szeto HH; publication type Research Support, N.I.H., Extramural. PMID 24134698 affiliation: Department of Pharmacology, Joan and Sanford I. Weill Medical College of Cornell University; last author Szeto HH; publication type Research Support, N.I.H., Extramural3 J Am Soc Nephrol 20134 Br J Pharmacol 2014
  • On ClinicalTrials.gov, Stealth BioTherapeutics is lead sponsor of 19 of the 21 records with elamipretide as an intervention; the other two are led by Children's Hospital of Philadelphia (NCT05168774) and David Marcinek (NCT07275424) (25 Oct 2026). Source sentencequery.intr elamipretide, 21 records; leadSponsor Stealth BioTherapeutics Inc. 19; NCT05168774 leadSponsor Children's Hospital of Philadelphia; NCT07275424 leadSponsor David Marcinek (25 Oct 2026)10 ClinicalTrials.gov search, 25 October 2026
  • The trial reports list ties to the sponsor: an author of the 2021 Barth syndrome trial report is employed by Stealth BioTherapeutics, three authors of the 2024 extension report are Stealth employees, and the MMPOWER-3 report lists a Stealth BioTherapeutics affiliation among its authors. Source sentencePMID 33077895: "J.C. is employed by Stealth BioTherapeutics of Newton, Massachusetts." PMID 38602181: "Anthony Abbruscato, John Campbell, and Jim Carr are employees of Stealth BioTherapeutics." PMID 37268435 affiliations: "Stealth BioTherapeutics (D.A.B.)"9 Genet Med 202124 Genet Med 20248 Neurology 2023
  • Among the laboratory studies, the 2020 cross-linking study at the University of Washington declares no competing interest; in the 2020 rat heart study two authors served as consultants for Stealth BioTherapeutics and one later joined the company; in the 2022 analogue study one author has financial interests in the company. Source sentencePMID 32554501: "The authors declare no competing interest.", affiliation Department of Genome Sciences, University of Washington. PMID 32680996: "D.A.B. and S.R.S. have served as consultants for Stealth BioTherapeutics [...] D.A.B. transitioned from academia to full-time employment with Stealth BioTherapeutics." PMID 35913044: "HS HHS does not hold any position in Stealth Biotherapeutics but has financial interests in the company."2 Proc Natl Acad Sci U S A 202016 Commun Biol 20207 eLife 2022
  • The PubMed records of the EMBRACE STEMI report (2016) and the PROGRESS-HF report (2020) hold no conflict of interest statement. Source sentencePubMed XML for 26586786 and 32068002: no CoiStatement element (25 Oct 2026)22 Eur Heart J 201623 J Card Fail 2020

Studies

  1. RodentJ Am Soc Nephrol 2013

    Cardiolipin binding by a fluorescent SS-31 analogue, cytochrome c peroxidase activity, and cristae membranes and ATP in rat kidneys during ischemia and reperfusion

    Design
    Laboratory binding study with a fluorescent analogue, plus a rat renal ischemia model
    Population or model
    isolated cardiolipin systems and rats (renal ischemia)
    Molecule
    SS-31 (elamipretide) exact

    No conflict of interest statement in the PubMed record; PubMed lists NIH extramural research support.

    PubMed 23813215DOI

  2. In vitro or ex vivoBr J Pharmacol 2014

    Binding to cardiolipin-containing membranes (fluorescence, turbidity, NMR), cytochrome c reduction and mitochondrial oxygen consumption

    Design
    Biophysical study in liposomes and bicelles, with assays in mitoplasts and isolated mitochondria
    Population or model
    liposomes, bicelles, mitoplasts, frozen and fresh mitochondria
    Molecule
    SS-31 (elamipretide) exact

    No conflict of interest statement in the PubMed record; PubMed lists NIH extramural research support.

    PubMed 24134698DOI

  3. In vitro or ex vivoProc Natl Acad Sci U S A 2020

    Protein interactors of SS-31 in mitochondria and the cross-linked residues, by chemical cross-linking mass spectrometry

    Design
    Chemical cross-linking with mass spectrometry in mitochondria
    Population or model
    mitochondria
    Molecule
    SS-31 (elamipretide) exact

    Competing interest statement: the authors declare no competing interest.

    PubMed 32554501DOI

  4. Analytical only (no biological model)Elife 2022

    Membrane-bound conformation by NMR and molecular dynamics, binding to cardiolipin-containing membranes, membrane surface charge, and mitochondrial membrane potential and ATP content in stressed cultured cells

    Design
    Structure and activity comparison of SS-31 and three tetrapeptide analogues (NMR, molecular dynamics, membrane binding, cell culture)
    Population or model
    membrane mimetics (bicelles) and mammalian cell culture
    Molecule
    SS-31 (elamipretide) exact
    Comparator
    Three tetrapeptide analogues

    One author (HHS) has financial interests in Stealth BioTherapeutics; the other authors declare no competing interests.

    PubMed 35913044DOI

  5. RodentCommun Biol 2020

    Activity of mitochondrial complexes I, II and IV, 3D cristae ultrastructure by serial block face electron microscopy, cardiolipin concentration by mass spectrometry

    Design
    Rat cardiac ischemia reperfusion model with biophysical membrane experiments
    Population or model
    rats (cardiac ischemia reperfusion)
    Molecule
    SS-31 (elamipretide) exact

    Two authors served as consultants for Stealth BioTherapeutics; one later became a full-time Stealth employee.

    PubMed 32680996DOI

  6. Human, randomisedEur Heart J 2016

    Infarct size by CK-MB area under the curve over 72 h (primary endpoint), with MRI, angiographic, electrocardiographic and clinical outcomes

    Design
    Multicentre randomised double-blind placebo controlled phase 2a trial
    Population or model
    adults with first anterior ST-elevation myocardial infarction undergoing primary PCI
    Molecule
    SS-31 (elamipretide) exact
    Comparator
    Placebo
    Blinding
    double-blind

    No conflict of interest statement in the PubMed record.

    PubMed 26586786DOI

  7. Human, randomisedGenet Med 2021

    6-minute walk test and the Barth Syndrome Symptom Assessment (primary endpoints), plus muscle strength, global impressions and cardiac parameters

    Design
    Randomised double-blind placebo controlled crossover trial followed by an open-label extension
    Population or model
    people with Barth syndrome
    Molecule
    SS-31 (elamipretide) exact
    n
    12
    Comparator
    Placebo (crossover)
    Blinding
    double-blind

    One author (J.C.) is employed by Stealth BioTherapeutics.

    PubMed 33077895DOI

  8. Human, randomisedNeurology 2023

    6-minute walk test and total fatigue on the Primary Mitochondrial Myopathy Symptom Assessment (primary endpoints), plus secondary symptom and global impression scores

    Design
    Phase 3 randomised double-blind placebo controlled trial
    Population or model
    people with genetically confirmed primary mitochondrial myopathy
    Molecule
    SS-31 (elamipretide) exact
    n
    218
    Comparator
    Placebo
    Blinding
    double-blind

    Most authors report research, trial or consulting funding from Stealth BioTherapeutics; one author is a Stealth employee.

    PubMed 37268435DOI

  9. Human, randomisedJ Card Fail 2020

    Left ventricular end systolic volume and ejection fraction by cardiac magnetic resonance imaging

    Design
    Phase 2 randomised double-blind placebo controlled trial with three arms
    Population or model
    adults with heart failure with reduced ejection fraction
    Molecule
    SS-31 (elamipretide) exact
    n
    71
    Comparator
    Placebo
    Blinding
    double-blind

    No conflict of interest statement in the PubMed record.

    PubMed 32068002DOI

  10. Human, uncontrolledGenet Med 2024

    Safety and tolerability (extension primary endpoints), 6-minute walk test, symptom scores, muscle strength, echocardiography, and cardiolipin and monolysocardiolipin values

    Design
    Open-label extension of a randomised trial, no placebo group
    Population or model
    people with Barth syndrome
    Molecule
    SS-31 (elamipretide) exact
    n
    10
    Blinding
    open-label

    Two authors received research support from Stealth BioTherapeutics; three authors are Stealth employees.

    PubMed 38602181DOI

Mechanisms studied

  • A 2013 study measured SS-31 binding to cardiolipin with a polarity-sensitive fluorescent analogue, measured cytochrome c peroxidase activity of the SS-31 and cardiolipin complex, and examined cristae membranes in rats during renal ischemia. Source sentenceAbstract: "we used a polarity-sensitive fluorescent analog of SS-31 [...] cardiolipin [...] the SS-31/cardiolipin complex [...] cytochrome c peroxidase activity [...] rats [...] cristae membranes during renal ischemia"3 J Am Soc Nephrol 2013
  • The 2014 study measured cytochrome c reduction in vitro and oxygen consumption in mitoplasts and in frozen and fresh mitochondria in the presence of SS-31 and added cardiolipin. Source sentenceEXPERIMENTAL APPROACH: "Effects of cardiolipin on electron transfer kinetics of cytochrome c were determined by cytochrome c reduction in vitro and oxygen consumption using mitoplasts, frozen and fresh mitochondria."4 Br J Pharmacol 2014
  • A 2020 study mapped SS-31 protein contacts in mitochondria by chemical cross-linking with mass spectrometry, including the cross-linked residues. Source sentenceAbstract: "Here we utilize chemical cross-linking with mass spectrometry to identify protein interactors of SS-31 in mitochondria. [...] Residues cross-linked with SS-31 [...]"2 Proc Natl Acad Sci U S A 2020
  • A 2020 rat heart ischemia reperfusion study measured the activity of complexes I, II and IV by respirometry in permeabilised ventricular fibres, cristae networks by serial block face electron microscopy and cardiolipin concentration by mass spectrometry. Source sentenceAbstract: "Respirometry with permeabilized ventricular fibers [...] the activity of complexes I, II, and IV [...] Serial block face scanning electron microscopy used to create 3D reconstructions of cristae ultrastructure [...] Mass spectrometry [...] cardiolipin concentration after ischemia-reperfusion"16 Commun Biol 2020
  • The 2022 study also measured binding of SS-31 and the three analogues to cardiolipin-containing membranes, membrane surface charge, and mitochondrial targeting in mammalian cell culture assays. Source sentenceAbstract: "[...] cardiolipin-containing membranes [...] membrane surface charge [...] to permeate cells and target mitochondria in mammalian cell culture assays"7 eLife 2022

Status matrix

European Union: EMA records

EU

  • No EU authorised medicine for elamipretide, SS-31 or MTP-131 was found in EMA medicines data on 25 Oct 2026. Source sentenceEMA medicines JSON, 2,754 records (timestamp 2026-10-24T18:22:32Z): 0 records matching elamipretide, SS-31 or MTP-13119 EMA medicines data, 25 October 2026
  • EMA's orphan designation data list two positive orphan designations for elamipretide, recorded for Barth syndrome and for myopathic mitochondrial DNA depletion syndrome. Source sentenceEMA orphan designations JSON, 3,310 records (timestamp 2026-10-24T18:31:05Z): active_substance elamipretide, intended_use "Treatment of Barth syndrome", status Positive; active_substance elamipretide, intended_use "Treatment of myopathic mitochondrial DNA depletion syndrome", status Positive20 EMA orphan designation data, 25 October 2026

United Kingdom: MHRA records

UK

Sport anti-doping list

International

  • The WADA 2026 Prohibited List, in effect from 1 Jan 2026, does not name SS-31, elamipretide or MTP-131 (text search of the list on 25 Oct 2026); it names MOTS-c, a different peptide, in class S4.4.1 (metabolic modulators). The 2027 list was not checked for this page. Source sentence"This List shall come into effect on 1 January 2026." No match for elamipretide, SS-31, SS31 or MTP-131 in the full text; S4.4. METABOLIC MODULATORS, S4.4.1: "mitochondrial open reading frame of the 12S rRNA-c (MOTS-c)"15 WADA Prohibited List 2026 (Internet Archive capture of 1 October 2025)

Registered trials

  • NCT03323749Phase 3

    Status
    Terminated (primary completion 10 Feb 2020)
    Sponsor
    Stealth BioTherapeutics Inc.
    Site countries
    Canada, Denmark, Germany, Hungary, Italy, UK, US
    Primary endpoint
    6-minute walk test and total fatigue score on the PMMSA
    Primary endpoint met
    not met
    Last synced
    25 October 2026

  • NCT05162768Phase 3

    Status
    Completed (primary completion 30 Sep 2024, study completion 4 Dec 2024); no results posted
    Sponsor
    Stealth BioTherapeutics Inc.
    Site countries
    Australia, Germany, Hungary, Italy, Netherlands, New Zealand, Norway, Spain, UK, US
    Primary endpoint
    6-minute walk test
    Primary endpoint met
    not reported
    Last synced
    25 October 2026

  • NCT07531251Phase 4

    Status
    Recruiting (estimated primary completion 30 Sep 2029)
    Sponsor
    Stealth BioTherapeutics Inc.
    Site countries
    Canada, UK, US
    Primary endpoint
    one primary endpoint, not named further in the record
    Primary endpoint met
    not reported
    Last synced
    25 October 2026
  • ClinicalTrials.gov on 25 Oct 2026: 21 records with elamipretide as an intervention (21 in a full text search), of which 14 completed, 3 terminated, 2 recruiting, 1 active and not recruiting and 1 expanded access record; 14 have posted results. Source sentencequery.intr elamipretide: countTotal 21; query.term elamipretide: 21; filter.overallStatus COMPLETED 14, TERMINATED 3, RECRUITING 2, ACTIVE_NOT_RECRUITING 1; NCT04689360 AVAILABLE; aggFilters results:with 1410 ClinicalTrials.gov search, 25 October 2026
  • MMPOWER-3 (NCT03323749) is recorded as terminated with the reason "Part1,double blind portion of the trial did not meet the primary end points". Source sentenceNCT03323749: overallStatus TERMINATED; whyStopped "Part1,double blind portion of the trial did not meet the primary end points"17 ClinicalTrials.gov NCT03323749
  • Site countries in the registry records: NCT03323749 Canada, Denmark, Germany, Hungary, Italy, the United Kingdom and the United States; NCT03098797 the United States; NCT05162768 Australia, Germany, Hungary, Italy, the Netherlands, New Zealand, Norway, Spain, the United Kingdom and the United States; NCT07531251 Canada, the United Kingdom and the United States. Source sentencecontactsLocationsModule.locations[].country (25 Oct 2026): NCT03323749 Canada, Denmark, Germany, Hungary, Italy, United Kingdom, United States; NCT03098797 United States; NCT05162768 Australia, Germany, Hungary, Italy, Netherlands, New Zealand, Norway, Spain, United Kingdom, United States; NCT07531251 Canada, United Kingdom, United States17 ClinicalTrials.gov NCT0332374918 ClinicalTrials.gov NCT0309879712 ClinicalTrials.gov NCT0516276811 ClinicalTrials.gov NCT07531251
  • Primary outcome measures as registered: NCT03323749 the six-minute walk test and the total fatigue score on the PMMSA; NCT03098797 distance walked in the 6-minute walk test and the total fatigue score on the BTHS-SA, both in part 1; NCT05162768 the six-minute walk test; NCT07531251 one primary endpoint, not named further in the record. Source sentenceoutcomesModule.primaryOutcomes[].measure (25 Oct 2026): NCT03323749 "Six-minute Walk Test (6MWT)", "Total Fatigue Score on the on the Primary Mitochondrial Myopathy Symptom Assessment (PMMSA)"; NCT03098797 "Part 1: Distance Walked During the 6-Minute Walk Test (6MWT) by Visit", "Part 1: Total Fatigue Score Based on the BTHS-SA by Visit."; NCT05162768 "Six-minute walk test (6MWT)"; NCT07531251 "Primary Efficacy End Point"17 ClinicalTrials.gov NCT0332374918 ClinicalTrials.gov NCT0309879712 ClinicalTrials.gov NCT0516276811 ClinicalTrials.gov NCT07531251

Timeline

  1. Fluorescent analogue study of SS-31 binding to cardiolipin published Source sentenceJ Am Soc Nephrol 2013 Jul;24(8):1250-61, Epub 11 Jul 2013: "a polarity-sensitive fluorescent analog of SS-31"3 J Am Soc Nephrol 2013
  2. Liposome, bicelle and NMR study of SS-31 and cardiolipin published Source sentenceBr J Pharmacol 2014 Apr;171(8):2017-28: "liposomes and bicelles [...] nuclear magnetic resonance"4 Br J Pharmacol 2014
  3. EMBRACE STEMI phase 2a trial report published online Source sentenceEur Heart J 2016;37:1296-303, Epub 19 Nov 2015: "EMBRACE STEMI is a multicentre, randomized, double-blind Phase 2a trial"22 Eur Heart J 2016
  4. Cross-linking mass spectrometry map of SS-31 protein contacts in mitochondria published Source sentenceProc Natl Acad Sci U S A 2020;117:15363-15373, Epub 17 Jun 2020: "chemical cross-linking with mass spectrometry to identify protein interactors of SS-31 in mitochondria"2 Proc Natl Acad Sci U S A 2020
  5. Report of a randomised crossover trial in Barth syndrome published online Source sentenceGenet Med 2021;23:471-478, Epub 20 Oct 2020: "randomized, double-blind, placebo-controlled crossover trial followed by an open-label extension in BTHS"9 Genet Med 2021
  6. MMPOWER-3 phase 3 report published online Source sentenceNeurology 2023;101:e238-e252, Epub 2 Jun 2023: "MMPOWER-3, a pivotal, phase-3, randomized, double-blind, placebo-controlled clinical trial"8 Neurology 2023
  7. Randomised phase 4 trial in Barth syndrome (NCT07531251) starts recruiting Source sentenceNCT07531251: startDate 2026-07-02 (ACTUAL); overallStatus RECRUITING; phases PHASE411 ClinicalTrials.gov NCT07531251

Integrity notes

  • PubMed CommentsCorrections and Crossref update-to were checked on 25 Oct 2026 for the studies on this page: no retraction, correction or expression of concern was found. The 2013 cardiolipin study has a linked commentary (PMID 23813213). Source sentencePubMed CommentsCorrections: 23813215 CommentIn 23813213 (Letter, Comment); none for 24134698, 32554501, 35913044, 32680996, 26586786, 33077895, 37268435, 32068002, 38602181; Crossref filter updates: 0 for each DOI (25 Oct 2026)3 J Am Soc Nephrol 20134 Br J Pharmacol 20142 Proc Natl Acad Sci U S A 20207 eLife 202216 Commun Biol 202022 Eur Heart J 20169 Genet Med 20218 Neurology 202323 J Card Fail 202024 Genet Med 2024
  • The search term SS-31 also matches records that are not about elamipretide: among the 18 records the query returns with the randomised controlled trial tag are a 2024 aficamten trial (PMID 39217569) and a 2012 metoclopramide formulation study (PMID 22328192), so the PubMed counts on this page include unrelated records. Source sentenceesearch ("SS-31"[tiab] OR elamipretide[tiab] OR "MTP-131"[tiab]) AND randomized controlled trial[pt]: count 18, idlist includes 39217569 (an aficamten trial, J Am Coll Cardiol 2024) and 22328192 (a metoclopramide formulation study, Eur J Drug Metab Pharmacokinet 2012) (25 Oct 2026)25 PubMed search for randomised trials of SS-31, 25 October 2026
  • The 2024 Barth syndrome report covers the open-label extension of the trial, a phase without a placebo group. Source sentenceAbstract: "TAZPOWER was a 28-week randomized, double-blind, and placebo-controlled trial followed by a 168-week OLE."24 Genet Med 2024

Chemistry and records

SS-31: sequence, mass, CAS and regulatory record in the research library →

Sources

  1. 1PubChem CID 11764719 accessed 25 Oct 2026
  2. 2Proc Natl Acad Sci U S A 2020 accessed 25 Oct 2026
  3. 3J Am Soc Nephrol 2013 accessed 25 Oct 2026
  4. 4Br J Pharmacol 2014 accessed 25 Oct 2026
  5. 5PubMed search for SS-31, elamipretide or MTP-131, 25 October 2026 accessed 25 Oct 2026
  6. 6PubMed search for reviews of SS-31, 25 October 2026 accessed 25 Oct 2026
  7. 7eLife 2022 accessed 25 Oct 2026
  8. 8Neurology 2023 accessed 25 Oct 2026
  9. 9Genet Med 2021 accessed 25 Oct 2026
  10. 10ClinicalTrials.gov search, 25 October 2026 accessed 25 Oct 2026
  11. 11ClinicalTrials.gov NCT07531251 accessed 25 Oct 2026
  12. 12ClinicalTrials.gov NCT05162768 accessed 25 Oct 2026
  13. 13PubChem CID 10008657 accessed 25 Oct 2026
  14. 14PubChem CID 146675088 accessed 25 Oct 2026
  15. 15WADA Prohibited List 2026 (Internet Archive capture of 1 October 2025) accessed 25 Oct 2026
  16. 16Commun Biol 2020 accessed 25 Oct 2026
  17. 17ClinicalTrials.gov NCT03323749 accessed 25 Oct 2026
  18. 18ClinicalTrials.gov NCT03098797 accessed 25 Oct 2026
  19. 19EMA medicines data, 25 October 2026 accessed 25 Oct 2026
  20. 20EMA orphan designation data, 25 October 2026 accessed 25 Oct 2026
  21. 21GOV.UK search for elamipretide, 25 October 2026 accessed 25 Oct 2026
  22. 22Eur Heart J 2016 accessed 25 Oct 2026
  23. 23J Card Fail 2020 accessed 25 Oct 2026
  24. 24Genet Med 2024 accessed 25 Oct 2026
  25. 25PubMed search for randomised trials of SS-31, 25 October 2026 accessed 25 Oct 2026

About this page

Research-use information. This library summarises published literature and regulator records. It is not guidance for use, not medical advice, and not a statement that any material is suitable for use in people or animals.

Reviewed by the Peptency editorial process. Version 1, last edited 25 October 2026, 25 sources.

Cite this page: Peptency Academy. SS-31 (elamipretide): chemistry, studies and regulator records. Version 1./eu/academy/compounds/ss-31/