Research use only ✓ COA SS-31

Longevity & Mitochondrial Peptides

SS-31 Elamipretide

Name: SS-31
Brand: Clean Peptide
Price: 64.79 USD
Availability: InStock

CAS 736992-21-5 BATCH ACE-7909990

SS-31 (elamipretide) is a synthetic tetrapeptide, D-Arg-Dmt-Lys-Phe-NH2, that binds cardiolipin in the inner mitochondrial membrane. These SS-31 research vials hold 10 mg or 50 mg of lyophilised peptide, and each size has its own ILS Laboratories certificate for HPLC purity, net content and identity.

Mass

Clear

Quantity

−30% applied

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Verified test results

Every batch, independently verified.

Each batch is analyzed by an ISO/IEC 17025 accredited third-party laboratory before it ships. This is the released report for the size selected above, exactly as the lab signed it.

ILS LaboratoriesIndependent, ISO/IEC 17025 accredited

Certificate of analysis

99.90%

Purity by HPLC

Lot: ACE-7909990
Tested: Sep 3, 2026
Labeled: 10mg
Measured: 10.72mg

ISO 17025 accredited7× tested

Full QC panel

5 passed · 2 reported

Purity

HPLC

99.90%Pass

Net Peptide Content

10.72mgReported

Identity

HPLC

SS-31Pass

Fentanyl Screen

Not DetectedPass

Heavy Metals

ICP-MS

Not DetectedPass

Sterility

PCR

No GrowthPass

Endotoxin

USP <85>

0.101 EU/mLReported

Every size on record

Open any size’s signed certificate. Your order ships with the report for the size you buy.

SS-31 10mg

Selected

LOT ACE-7909990

99.90%

HPLC purity · meets spec

Labeled: 10mg
Measured: 10.72mg
Identity: SS-31
Heavy metals: Not Detected
Sterility: No Growth
Endotoxin: 0.101 EU/mL
Tested: Sep 3, 2026

5 assays passed · ILS Laboratories, ISO/IEC 17025 accredited

SS-31 50mg

Selected

LOT ACE-2817021

99.90%

HPLC purity · meets spec

Labeled: 50mg
Measured: 51.82mg
Identity: SS-31
Heavy metals: Not Detected
Sterility: No Growth
Endotoxin: 0.101 EU/mL
Tested: Sep 3, 2026

5 assays passed · ILS Laboratories, ISO/IEC 17025 accredited

What is SS-31?

SS-31 is the lead compound of the Szeto-Schiller (SS) peptides, designed by Hazel Szeto at Weill Cornell and Peter Schiller in Montreal. It is only four residues long but unusual in two of them: the arginine is the D-isomer, and the second residue is 2′,6′-dimethyltyrosine (Dmt), a non-natural amino acid. The pattern of alternating aromatic and positively charged residues lets it cross cell membranes and concentrate in mitochondria; the 2004 paper describing the series reported roughly 1,000-fold concentration in the inner mitochondrial membrane.

Its target is cardiolipin, the negatively charged phospholipid found almost only in the inner mitochondrial membrane, where it shapes the cristae. In 2013 SS-31 was reported to bind cardiolipin with high affinity and to inhibit the cytochrome c peroxidase activity that oxidises it. Under the name elamipretide, it was developed clinically by Stealth BioTherapeutics and became the first FDA-approved drug in its class in 2025. It is sometimes grouped with MOTS-c, a very different molecule: a natural 16-residue peptide encoded in mitochondrial DNA.

SS-31 identity

Names	SS-31, SS31, elamipretide (INN), MTP-131, Bendavia, Szeto-Schiller peptide 31; brand name Forzinity (Stealth BioTherapeutics)
Sequence	`D-Arg-Dmt-Lys-Phe-NH2` (Dmt = 2′,6′-dimethyl-L-tyrosine)
Stereochemistry	D-arginine; Dmt, Lys and Phe are L
Length	4 residues, C-terminal amide
Molecular formula	C₃₂H₄₉N₉O₅ (free base)
Molecular weight	639.8 g/mol (free base); the approved drug is the trihydrochloride, 749.2 g/mol
CAS number	736992-21-5 (free base); 2244098-12-0 (hydrochloride)
PubChem CID	11764719
Target	Cardiolipin, inner mitochondrial membrane
This product	10 mg and 50 mg, lyophilised powder

Sources: the Forzinity label on DailyMed, the FDA substance registry (GSRS) and PubChem.

Certificates for the current lots

Each size is filled from its own lot and analysed separately by ILS Laboratories in San Diego, which states ISO/IEC 17025 accreditation for activities within its published scope. Both certificates are full QC panels: HPLC purity, net peptide content and identity, plus endotoxin, sterility, heavy metals by ICP-MS and a fentanyl screen:

Size	Lot	Laboratory	Analysed	HPLC purity	Measured content	Identity
10mg	ACE-7909990	ILS Laboratories	3 Sep 2026	99.90%	10.72mg	SS-31
50mg	ACE-2817021	ILS Laboratories	3 Sep 2026	99.90%	51.82mg	SS-31

Transcribed from the certificate issued for each size on sale today. Open the signed certificate for any size under Verified test results above. Every SS-31 COA, lot by lot

Published research on SS-31

The SS peptide series (2004). Cell-permeable peptides built on alternating aromatic and basic residues, with dimethyltyrosine as the antioxidant group, concentrated in the inner mitochondrial membrane and reduced reactive oxygen species, swelling and cytochrome c release in cells and isolated mitochondria. Cell-permeable peptide antioxidants targeted to inner mitochondrial membrane inhibit mitochondrial swelling, oxidative cell death, and reperfusion injury. Zhao K, et al. Journal of Biological Chemistry, 2004.
Cardiolipin binding (2013). SS-31 bound cardiolipin with high affinity, and in a rat renal ischaemia model pretreatment preserved cristae membranes and sped ATP recovery on reperfusion. The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin. Birk AV, et al. Journal of the American Society of Nephrology, 2013.
Aged mouse muscle (2013). One hour after a single dose, spectroscopy measures of mitochondrial ATP production and coupling in the muscle of 27-month-old mice moved toward those of young mice; young mice showed no change. Siegel MP, et al. Aging Cell, 2013.
Dogs with heart failure (2016). Three months of elamipretide in a microembolisation model, with left-ventricular function and cardiomyocyte mitochondrial respiration as end points. Sabbah HN, et al. Circulation: Heart Failure, 2016.
Barth syndrome, TAZPOWER (2021, 2024). A 12-patient crossover trial that did not meet its primary end points, followed by an open-label extension in which 8 patients reached 168 weeks. Barth syndrome is a genetic defect of cardiolipin remodelling. Reid Thompson W, et al. Genetics in Medicine, 2021; Thompson WR, et al. Genetics in Medicine, 2024.
Primary mitochondrial myopathy, MMPOWER-3 (2023). A 24-week phase 3 trial in 218 adults that did not meet either primary end point (six-minute walk distance and fatigue score). Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial. Karaa A, et al. Neurology, 2023.
Heart failure and dry AMD (2020, 2025). PROGRESS-HF (71 patients, 4 weeks) found no change in left-ventricular end-systolic volume against placebo; ReCLAIM-2 (176 patients with geographic atrophy, 48 weeks) did not reach significance on its primary end points. Butler J, et al. Journal of Cardiac Failure, 2020; Ehlers JP, et al. Ophthalmology Science, 2025.

A phase 3 trial in dry AMD (ReNEW, NCT06373731) and the post-approval confirmatory trial in Barth syndrome (NCT07531251) were under way in October 2026.

Regulatory status

Elamipretide is an FDA-approved drug for one indication. On 19 September 2025 FDA granted accelerated approval to Forzinity (Stealth BioTherapeutics) to improve muscle strength in adult and paediatric patients with Barth syndrome weighing at least 30 kg; continued approval depends on a confirmatory trial. All other uses, including mitochondrial myopathy, heart failure and macular degeneration, remain investigational. Forzinity prescribing information, DailyMed; FDA approval letter, NDA 215244. Clean Peptide’s SS-31 is a laboratory reference material, not Stealth’s product, and is not for human or veterinary use.

Related research

MOTS-c, the mitochondrial-DNA-encoded peptide, with its own certificates.
Epithalon and NAD+ in cellular-ageing research.
Peptide testing: what each line of a full QC panel shows.
All mitochondrial peptides.

Technical specification

What is on file, and how it is handled

Every figure below is transcribed from the paperwork for this compound.

Material

Compound: SS-31 (Elamipretide)
Class: Cardiolipin-binding tetrapeptide (Szeto-Schiller peptide)
Form: Lyophilised powder
Sizes: 10mg, 50mg
Sequence: D-Arg-Dmt-Lys-Phe-NH2 (Dmt = 2',6'-dimethyl-L-tyrosine)
Formula: C32H49N9O5
CAS: 736992-21-5
Mol. weight: 639.8 g/mol
Residues: 4

Verification

Identity: Confirmed on the certificate of analysis
Purity: ≥ 99.9% by HPLC
Batch: ACE-7909990
Documentation: Per-batch certificate of analysis

Handling

Storage: Store at −20 °C, protected from light
Intended use: In-vitro laboratory research only

Compound data on PubChem

QuestionsSS-31: frequently asked

What is SS-31?+

SS-31 (elamipretide) is a synthetic tetrapeptide, D-Arg-Dmt-Lys-Phe-NH2, from the Szeto-Schiller peptide series. It concentrates in mitochondria and binds cardiolipin, a phospholipid of the inner mitochondrial membrane.

Is SS-31 the same as elamipretide?+

Yes. Elamipretide is the international non-proprietary name of SS-31; it was also developed under the codes MTP-131 and Bendavia. The FDA-approved drug Forzinity contains elamipretide as its hydrochloride salt.

Is SS-31 FDA-approved?+

Elamipretide received FDA accelerated approval on 19 September 2025, as Forzinity, for one indication: improving muscle strength in patients with Barth syndrome weighing at least 30 kg. Other uses are investigational. Clean Peptide’s SS-31 is a laboratory reference material, not that product.

What is the SS-31 molecular weight?+

639.8 g/mol for the free base, C32H49N9O5 (CAS 736992-21-5, PubChem CID 11764719). The approved drug’s trihydrochloride salt is 749.2 g/mol.

What is the difference between SS-31 and MOTS-c?+

SS-31 is a synthetic 4-residue peptide with a D-amino acid and a non-natural dimethyltyrosine that binds cardiolipin. MOTS-c is a natural 16-residue peptide encoded in the mitochondrial 12S rRNA gene, studied for its effects through AMPK.

What do the SS-31 certificates show?+

Each size has its own ILS Laboratories full QC panel, listed on this page with lot number, test date, HPLC purity, net peptide content and identity; the certificates also report endotoxin, sterility, heavy metals and a fentanyl screen.

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