Name: SS-31
Brand: PeptidesDirect
SKU: PD-SS31-50MG
Availability: InStock

Question 1

What is SS-31?

Accepted Answer

SS-31 (also known as Elamipretide or Bendavia) is a mitochondria-targeted tetrapeptide (D-Arg-Dmt-Lys-Phe-NH2). It is studied for its ability to selectively target and concentrate in the inner mitochondrial membrane, where it interacts with cardiolipin.

Question 2

How should I store SS-31?

Accepted Answer

Store lyophilized SS-31 at -20°C for long-term storage or at 2-8°C for short-term use. After reconstitution, keep refrigerated at 2-8°C and use within 30 days. Protect from light.

Question 3

What purity is your SS-31?

Accepted Answer

Every batch of SS-31 ships with a certificate of analysis from Janoshik Analytical, an independent third-party laboratory, at a minimum purity of 98%. We do not run a lab ourselves: the manufacturer commissions this test, and we pass the report on unchanged, with an online verification link on the product page. This batch also carries a second, independent test from Kovera Labs, commissioned outside the manufacturer.

Question 4

How do I reconstitute SS-31?

Accepted Answer

Add bacteriostatic water slowly along the inside wall of the vial. Gently swirl - do not shake. Use 1-2 mL of bacteriostatic water per vial. Ensure the solution is clear before use.

Question 5

What has SS-31 (elamipretide) actually been studied for, and in which species?

Accepted Answer

In humans, SS-31 (elamipretide) has been tested in randomized, placebo-controlled trials for heart failure with reduced ejection fraction (PMID 29217757, PMID 32068002) and primary mitochondrial myopathy (PMID 29500292, PMID 32096613, PMID 37268435), and in a single-center, open-label trial for dry age-related macular degeneration with geographic atrophy (PMID 36246181). In mice, it has been studied for age-related cardiac diastolic dysfunction (PMID 32648542). Most of these efficacy trials, including the two largest (PROGRESS-HF, n=71, and MMPOWER-3, n=218), did not meet their primary endpoint; a separate, narrower trial in Barth syndrome using a muscle-strength measure led to a 2025 FDA accelerated approval for that one condition only.

Question 6

What dose have SS-31 (elamipretide) research trials used, and is there a published human dosing protocol?

Accepted Answer

In the first human heart-failure trial, adults with reduced ejection fraction received a single 4-hour intravenous infusion of up to 0.25 mg/kg/h (PMID 29217757); in the mitochondrial myopathy dose-escalation trial, the same top rate, 0.25 mg/kg/h, was given as a 2-hour intravenous infusion daily for 5 days (PMID 29500292). That is what those two trials administered. Later human trials switched to flat subcutaneous daily doses not reported per kilogram: MMPOWER-2, MMPOWER-3 and ReCLAIM used 40 mg/day, while PROGRESS-HF tested two dose levels, 4 mg/day and 40 mg/day. A mouse cardiac-aging study used 3 mg/kg/day by continuous subcutaneous infusion for 8 weeks (PMID 32648542). No general human dosing protocol has been published for this compound: the only FDA-approved dosing (FORZINITY, for muscle strength in Barth syndrome patients weighing 30 kg or more) is a separate, different regulatory product, not this research peptide.

Question 7

What side effects were actually reported in SS-31 (elamipretide) human trials, and at what rates?

Accepted Answer

The most consistently reported adverse event across trials is injection site reaction: 80% of participants in the MMPOWER-2 subcutaneous myopathy trial had one, mostly mild, with no serious adverse events or deaths (PMID 32096613). In the ReCLAIM AMD trial, all 19 participants had at least one non-ocular adverse event (73.7% mild, 26.3% moderate), and two withdrew for adverse-event reasons, one for an intolerable injection-site reaction and one for conversion to neovascular AMD (PMID 36246181). In the single-dose intravenous heart-failure trial, there were no serious adverse events, and blood pressure and heart rate stayed stable across all dose cohorts (PMID 29217757). Across the larger PROGRESS-HF (28 days) and MMPOWER-3 (24 weeks) trials, rates of drug-related adverse events were similar to placebo and the drug was described as well tolerated (PMID 32068002, PMID 37268435), but that label applies to trials that also did not beat placebo on their actual efficacy endpoint.

Question 8

What is not known about SS-31 (elamipretide) long-term safety, i.e. what is the honest gap in the evidence?

Accepted Answer

The longest published continuous daily-dosing exposure is actually a 168-week (about 3.2-year) open-label extension in Barth syndrome patients who stayed on the same 40 mg/day subcutaneous dose, but only 10 patients entered it and 8 reached week 168, with no placebo arm (PMID 38602181); among the larger, placebo-controlled trials, the longest is 24 weeks (MMPOWER-3, PMID 37268435), and there is still no published multi-year, placebo-controlled safety dataset in more than a handful of patients. The pivotal efficacy trials in heart failure (PROGRESS-HF, PMID 32068002) and in mitochondrial myopathy (MMPOWER-2, PMID 32096613; MMPOWER-3, PMID 37268435) all failed their primary endpoint, so the 'well tolerated' label mostly sits on trials that did not show the clinical benefit they were testing for. Trial sizes are small (n=10 to n=218), several were funded by or involved the manufacturer Stealth BioTherapeutics, and the myopathy-trial authors disclose extensive Stealth funding and consulting relationships. Even the one narrow FDA approval (Barth syndrome, muscle strength, patients weighing 30 kg or more) came with a mandatory confirmatory trial as a condition of keeping that accelerated approval, meaning the regulator itself has not treated the current data as final (PMID 41260682, PMID 41335372).

Question 9

How many SS-31 (elamipretide) trials actually met their primary endpoint, versus failed?

Accepted Answer

Of the human efficacy trials with a clear primary endpoint, most failed: PROGRESS-HF missed its primary left-ventricular volume endpoint at every dose (P=0.90 and P=0.28 versus placebo, PMID 32068002), MMPOWER-2 missed its primary 6-minute-walk endpoint (19.8 m difference, P=0.0833, PMID 32096613), and the larger phase 3 MMPOWER-3 missed both co-primary endpoints, 6-minute walk and fatigue score (PMID 37268435). The clearest positive human signals are short and mechanistic rather than confirmed clinical outcomes: a single IV infusion transiently lowered left-ventricular volumes in heart failure (PMID 29217757), and a 5-day IV dose-escalation study showed a near-significant gain in walk distance in myopathy in its main comparison (P=0.053, PMID 29500292), though a covariate-adjusted analysis in the same trial did reach significance (P=0.0297). The one open-label, uncontrolled trial in dry AMD reported visual-acuity gains, but without a placebo arm those gains cannot be attributed to the drug with confidence (PMID 36246181). Outside these, only a single-lab mouse study (PMID 32648542) and the narrow, surrogate-based Barth syndrome approval have produced a clearly positive result.

Question 10

Is SS-31 (elamipretide) approved by the FDA or any other regulator?

Accepted Answer

Yes, but only for one narrow use. On September 19, 2025, the FDA granted accelerated approval to elamipretide, marketed as FORZINITY, to improve muscle strength in adults and children with Barth syndrome who weigh 30 kg or more (PMID 41335372, PMID 41260682). That approval rests on a surrogate strength measure, granted after the drug's own pivotal randomized trial in that population missed its 6-minute-walk and fatigue endpoints, and a confirmatory trial is a required condition of keeping the approval (PMID 41260682). Elamipretide is not approved for heart failure, mitochondrial myopathy outside Barth syndrome, macular degeneration, cardiac aging, or any longevity or anti-aging use, and no EMA (EU) approval has been found as of this writing.

Question 11

Is the SS-31 vial sold here the same product as the FDA-approved drug FORZINITY?

Accepted Answer

No. FORZINITY is an FDA-approved pharmaceutical product, manufactured under the drug-grade controls FDA approval requires, sold only by prescription for one indication: muscle strength in Barth syndrome patients weighing 30 kg or more. What we sell is the same peptide sequence, elamipretide/SS-31, supplied and labeled as a research chemical, not manufactured, tested, or approved as a drug, and not intended for any of the uses studied in the trials described in these questions. Our own certificate of analysis speaks to the identity and purity of the peptide itself, not to the sterility, manufacturing, or regulatory oversight that applies to FORZINITY.

Question 12

Are SS-31, elamipretide, MTP-131, and Bendavia the same compound?

Accepted Answer

Yes, all four names refer to the same D-Arg-Dmt-Lys-Phe-NH2 tetrapeptide, just from different points in its history. SS-31 is the original laboratory name; MTP-131 was the developmental code name used in the first published human trial, titled 'A Study Investigating the Safety, Tolerability, and Efficacy of MTP-131 for the Treatment of Mitochondrial Myopathy' (PMID 29500292); Bendavia was the trade name used by the same company (then called Stealth Peptides, later renamed Stealth BioTherapeutics) for the same molecule; and elamipretide is the compound's current International Nonproprietary Name, used in all later trials (PMID 29217757, PMID 32096613, PMID 32068002, PMID 36246181) and in the 2025 FDA-approved drug FORZINITY (PMID 41335372).

Question 13

Did any SS-31 (elamipretide) trial measure an effect on blood pressure or heart rate?

Accepted Answer

Yes. In the single-dose intravenous heart-failure trial, blood pressure and heart rate were assessed at every timepoint and remained stable across all three dose cohorts, up to 0.25 mg/kg/h, and versus placebo (PMID 29217757). None of the trials reviewed here reported a clinically significant change in blood pressure or heart rate, in either direction. This is a narrow hemodynamic-safety finding from one 4-hour infusion study and the general safety reporting of the other trials, not a statement about long-term cardiovascular effects.

Question 14

Have SS-31 (elamipretide) trials used intravenous infusion or subcutaneous injection, and does the route matter?

Accepted Answer

Both. The two earliest human trials used intravenous infusion in a clinical setting, a single 4-hour infusion for heart failure (PMID 29217757) and daily 2-hour infusions for 5 days in mitochondrial myopathy (PMID 29500292), while every later human trial (MMPOWER-2, MMPOWER-3, PROGRESS-HF, ReCLAIM) switched to daily subcutaneous injection: 40 mg/day in MMPOWER-2, MMPOWER-3 and ReCLAIM, and either 4 mg/day or 40 mg/day in the two PROGRESS-HF dose arms. The route changes what the numbers mean: the IV trials report dose as mg/kg/h because an infusion delivers a controlled rate over time, while the SC trials report a flat daily mg amount with no published per-kilogram conversion, so an IV mg/kg/h figure and an SC mg/day figure cannot be directly compared.

Question 15

Is there published evidence that SS-31 slows aging or extends lifespan in humans?

Accepted Answer

No. The only aging-related study in the published research is a mouse model of age-related cardiac diastolic dysfunction, where 8 weeks of SS-31 improved heart function markers in old mice compared with saline-treated old mice (PMID 32648542); there is no published human lifespan, biological-age, or longevity-outcome trial for this compound. Even the 2025 FDA approval is for muscle strength in one specific rare genetic disease, Barth syndrome, and is explicitly not an approval for aging, longevity, or general mitochondrial support in healthy people. Marketing SS-31 as an anti-aging compound for humans goes beyond what any study listed here has actually measured.

Question 16

What does our own third-party CoA show for SS-31, and how can a specific batch be verified?

Accepted Answer

We currently have three published batch reports for SS-31: a Janoshik-tested Blue 10 mg batch at 99.7% purity with 10.31 mg content, a Janoshik-tested Black 50 mg batch at 99.75% purity with 45.42 mg content, and a Kovera Labs-tested Black-cap 10 mg batch (V2606-SS10-2401) at 99.87% purity with 9.11 mg content. The two Janoshik reports are manufacturer-commissioned, the standard testing that comes bundled with the product; the Kovera Labs report is a community-submitted test obtained independently of us and the manufacturer, not a blanket 'independently tested' claim for every batch. Each vial's cap or label color corresponds to one of these batches rather than a printed lot number or QR code, and the Janoshik reports carry a live verification link at verify.janoshik.com while the Kovera Labs report verifies at koveralabs.com, so a customer can match the color on their vial to the actual chromatogram.

Question 17

How does SS-31 compare to MOTS-c, since both are marketed as mitochondria-related peptides?

Accepted Answer

They act on different parts of mitochondrial biology and have never been tested against each other or in combination. SS-31 is a synthetic tetrapeptide that binds the inner-membrane phospholipid cardiolipin and has been studied mainly in cardiac and muscle disease trials described above, delivered by infusion or injection (PMID 29217757, PMID 29500292). MOTS-c is a naturally occurring 16-amino-acid peptide encoded in mitochondrial DNA that activates the cellular energy sensor AMPK; it has been studied in mice for insulin sensitivity and diet-induced obesity (PMID 25738459) and, in a separate paper, for exercise capacity and physical performance in young, middle-aged and old mice (PMID 33473109). Unlike SS-31, MOTS-c has no published human interventional trial of the peptide itself, only observational data showing that exercise raises the body's own MOTS-c levels. Because they work through different mechanisms and no study of either compound has tested combining them, nothing in the published record supports a specific SS-31/MOTS-c combination.

Question 18

Is SS-31 (elamipretide) on the WADA Prohibited List, and did its anti-doping status change after the September 2025 FDA approval?

Accepted Answer

Before the FDA's September 19, 2025 accelerated approval of elamipretide (marketed as FORZINITY, for Barth syndrome muscle strength only), the compound had no approval anywhere for human therapeutic use, exactly the condition that puts a substance under WADA's S0, Non-Approved Substances, category: prohibited at all times, in and out of competition. That approval changes the picture, since S0 only applies to substances with no current government approval, and elamipretide's cardiolipin-binding mechanism does not match a named category like S2 (growth factors) or S4 (hormone and metabolic modulators) either. Its status could still shift on WADA's next annual list review; this is informational only, and anyone bound by the WADA code should check the current official Prohibited List directly.

Question 19

Who discovered SS-31, and what does the "SS" in the name actually stand for?

Accepted Answer

SS-31 takes its name from its discoverers, Weill Cornell pharmacologist Hazel H. Szeto and Montreal peptide chemist Peter W. Schiller: "SS" stands for Szeto-Schiller. Their lab was working on a series of small aromatic-cationic peptides related to opioid-receptor chemistry when they found, by what Szeto's own account calls serendipity, that certain analogs concentrated in mitochondria and protected the inner membrane instead of acting on opioid receptors at all (Szeto, "Serendipity and the Discovery of Novel Compounds That Restore Mitochondrial Plasticity," Clinical Pharmacology and Therapeutics, 2014, PMID 25188726). The foundational mechanistic paper, describing these cell-permeable peptide antioxidants that concentrate at the inner mitochondrial membrane and blunt oxidative damage, the same compound now called elamipretide, was published by Zhao, Schiller, Szeto and colleagues in the Journal of Biological Chemistry in 2004 (PMID 15178689); the specific finding that SS-31 binds the inner-membrane phospholipid cardiolipin came later, from Birk and colleagues in 2013 (PMID 23813215).

Question 20

How much bacteriostatic water should be used to reconstitute a given SS-31 vial size, and how should the reconstituted solution be stored (fridge vs freezer, how many days/weeks it stays stable)?

Accepted Answer

Our SS-31 vials (10 mg and 50 mg) follow the same reconstitution convention used across our catalogue: add bacteriostatic water slowly down the inside wall of the vial, then swirl gently, never shake, until clear. The volume chosen, commonly 1-2 mL per 10 mg, only sets the resulting mg/mL concentration, it does not change the total peptide content or its chemical stability. Once dissolved, refrigerate at 2-8°C, protect from light, and avoid freeze-thaw cycles. As with our other reconstituted lyophilized peptides, use within about 2-4 weeks: no published stability study has set an exact shelf life for reconstituted SS-31 specifically, so this is standard peptide-handling practice, not a study finding.

Question 21

Does SS-31 (elamipretide) have any known drug interactions or contraindications, e.g. with blood thinners, kidney function, or other medications?

Accepted Answer

FDA prescribing information for FORZINITY (elamipretide) reports no classic CYP450 drug-interaction signal, since the drug is injected and bypasses the liver-enzyme pathway most oral medications go through: no blood-thinner-specific interaction has been described in the trials or the label. The label does address kidney function: elamipretide is cleared renally, and dosing in patients with significant renal impairment is adjusted under a physician's supervision. It also lists hypersensitivity to elamipretide or to benzyl alcohol, a preservative in the approved formulation, as a contraindication. All of this describes FORZINITY as prescribed to Barth syndrome patients under medical monitoring, not the unapproved research peptide sold here.

Question 22

How quickly do SS-31 (elamipretide) trials show an effect, and over what timeframe (weeks vs months)?

Accepted Answer

Timeframe varies by trial, not a single onset curve. The earliest human signal was immediate: a single 4-hour IV infusion changed cardiac volumes in heart failure patients by the end of that infusion (PMID 29217757), and a 5-day IV course showed a near-significant walk-distance gain in myopathy by day 5 (PMID 29500292). Subcutaneous trials ran longer: MMPOWER-2's 4-week arms missed the primary walk-distance endpoint (PMID 32096613), PROGRESS-HF found no effect at 28 days (PMID 32068002), and ReCLAIM reported visual-acuity gains by week 24, open-label (PMID 36246181). The longest continuous dosing on record, a 168-week Barth syndrome extension (PMID 38602181), has no placebo arm. None of this is a projectable timeline outside those specific trials.

Question 23

Can SS-31 be combined or 'stacked' with MOTS-c or NAD+ for mitochondrial research, and is there any published study testing them together?

Accepted Answer

No published study has tested SS-31 (elamipretide) and MOTS-c together, and none has tested SS-31 with NAD+ either: each has only been studied on its own. SS-31 binds cardiolipin in the inner mitochondrial membrane (PMID 29217757, PMID 29500292); MOTS-c activates the cellular energy sensor AMPK (PMID 25738459, PMID 33473109); NAD+ supplementation works through a separate pathway, replenishing the coenzyme pool mitochondrial enzymes and sirtuins consume. Different mechanisms do not by themselves predict how, or whether, compounds behave when combined; that requires its own study. Combining any of these three is a research-market practice built on their individual profiles, not a protocol any published study has actually tested.

Question 24

Is it still legal to sell and buy SS-31 as a research chemical in the EU now that elamipretide is FDA-approved as the prescription drug Forzinity?

Accepted Answer

FORZINITY's FDA approval is a US prescription-drug approval for one narrow use, muscle strength in Barth syndrome patients weighing 30 kg or more; it does not create or change any EU marketing authorization, and no EMA approval for elamipretide has been found. What we sell is the same peptide sequence, supplied and sold strictly for in-vitro laboratory research, not for human or animal use, and it remains a separate, unapproved research chemical from FORZINITY regardless of that US approval. We are not positioned to give a country-by-country legal opinion on research-chemical sales; our research-use-only terms, stated on every product page and in our terms of service, set the actual condition of sale.

SS-31

What is SS-31

How it works

Often studied alongside

Documentation

Storage and stability

Frequently Asked Questions

Technical data sheet

Frequently bought together

MOTS-c

NAD+

Epitalon

Bacteriostatic Water

Lab Measuring Syringe + Prep Wipes Set (1 mL 31G)

Graduated Measuring Syringe 1 mL 31G x 6 mm

Alcohol Prep Pads 30 x 65 mm

Peptide Storage Box (10 Compartments)

Peptide Vial Case 30 Slots