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SS-31 Dosage Chart: The Forzinity Label, Trials and Units

SS-31 is elamipretide, approved as Forzinity in 2025. The label's 40 mg daily dose, the trial and vendor figures, dated, with units for 5, 10 and 50 mg vials.

Medibact Guides · Published 2026-09-18

Illustration: Three clear glass vials with varying liquid levels on a white lab bench, precisely arranged.
Illustration

SS-31 is the compound on this site whose dosage record changed most recently. Until September 2025 elamipretide, the molecule sold under the research name SS-31, had trials but no label; since 2025-09-19 it has had one, and the label states a daily dose, a concentration and a volume. That makes it possible to put a regulator's figure beside the figures vendors cite, which turn out to be a quarter to an eighth of it. This page reports the label, the trials and the vendor figures, each dated, and works the arithmetic for the 5 mg, 10 mg and 50 mg vials the research market sells.

Elamipretide is a synthetic tetrapeptide that binds cardiolipin in the inner mitochondrial membrane, developed by Stealth BioTherapeutics and approved as Forzinity for Barth syndrome. Medibact's SS-31 guide covers the molecule and its evidence; this page stays with figures. The dosage hub lists every compound's page.

What the sources state

Source Kind Figure Date read
Forzinity label, Stealth BioTherapeutics (effective 2025-12-10; DailyMed version published 2025-12-12) Approved label 40 mg subcutaneously once daily, weight at least 30 kg; 20 mg once daily if eGFR below 30; 280 mg/3.5 mL (80 mg/mL) single-patient-use vial, discard 8 days after first opening 2026-09-18
FDA accelerated approval, 2025-09-19 Regulator action Indication: to improve muscle strength in adult and paediatric patients with Barth syndrome weighing at least 30 kg 2026-09-18
TAZPOWER, NCT03098797 (12 participants; results posted 2024-04-16) Trial protocol 40 mg subcutaneously once daily; 12-week crossover periods with 4-week washout; open-label extension up to 168 weeks 2026-09-18
Thompson et al., Genet Med 2024 (PMID 38602181) Trial publication 40 mg daily; cumulative 96.1 m six-minute-walk improvement at week 168; 8 of 10 reached week 168 2026-09-18
MMPOWER-3, NCT03323749 (218 participants; results posted 2021-04-02) Trial protocol 40 mg (0.5 mL) subcutaneously once daily for 24 weeks vs placebo; terminated 2026-09-18
DailyMed SPL search, "elamipretide" Label search One record, Forzinity 2026-09-18
Vendor and calculator pages Commonly cited 5 to 10 mg once daily; some 30 to 80 mg a day 2026-09-18

The label and the two trials state one figure between them. The vendor row states a range that does not contain it at the low end and contains it only by accident at the high end.

The label's own arithmetic

Forzinity is supplied as 280 mg in 3.5 mL, which is 80 mg/mL. The 40 mg daily dose is therefore 0.5 mL, and on a U-100 syringe 0.5 mL is 50 units; the 20 mg renal dose is 0.25 mL, or 25 units. Seven daily 0.5 mL doses use 3.5 mL, the whole vial, and the label's instruction to discard 8 days after first opening fits that arithmetic. Those are the only unit figures on this page that come from a label.

Units per amount at each research-vial size

Research-market SS-31 is supplied in 5 mg, 10 mg and 50 mg vials. The table takes each at 1, 2 and 3 mL of water, states the concentration, and converts four figures into U-100 syringe units (100 units = 1 mL): the vendor figures of 5 and 10 mg, the label's renal 20 mg, and the label and trial figure of 40 mg. A cell over 100 units does not fit one syringe.

Vial Water added Concentration 5 mg 10 mg 20 mg 40 mg
5 mg 1 mL 5 mg/mL 100 200 (>1 syringe) 400 (>1 syringe) 800 (>1 syringe)
5 mg 2 mL 2.5 mg/mL 200 (>1 syringe) 400 (>1 syringe) 800 (>1 syringe) 1,600 (>1 syringe)
5 mg 3 mL 1.67 mg/mL 300 (>1 syringe) 600 (>1 syringe) 1,200 (>1 syringe) 2,400 (>1 syringe)
10 mg 1 mL 10 mg/mL 50 100 200 (>1 syringe) 400 (>1 syringe)
10 mg 2 mL 5 mg/mL 100 200 (>1 syringe) 400 (>1 syringe) 800 (>1 syringe)
10 mg 3 mL 3.33 mg/mL 150 (>1 syringe) 300 (>1 syringe) 600 (>1 syringe) 1,200 (>1 syringe)
50 mg 1 mL 50 mg/mL 10 20 40 80
50 mg 2 mL 25 mg/mL 20 40 80 160 (>1 syringe)
50 mg 3 mL 16.67 mg/mL 30 60 120 (>1 syringe) 240 (>1 syringe)

The table makes the scale problem visible. A 5 mg vial is one 5 mg amount and one eighth of a 40 mg amount; the 20 mg and 40 mg columns are arithmetic only, since no draw can exceed what the vial holds. The 50 mg vial at 1 mL is the only row in which the label figure fits a single syringe, at 80 units, and even that is 30 units more than the approved product needs for the same milligrams, because the approved product is 80 mg/mL. The SS-31 calculator works any combination entered.

What the figures omit

The label attaches a single ultra-rare indication, a weight threshold, a renal adjustment, a defined solution and a discard rule. The trials attach populations with Barth syndrome or primary mitochondrial myopathy, durations of 12 to 168 weeks, and in MMPOWER-3 a termination. The accelerated approval rests on a 12-person crossover trial and its extension, and the FDA's own materials describe the crossover phase as not reaching statistical significance on its primary endpoints, with the approval resting on knee-extensor strength in the extension. The vendor figures attach nothing. A research vial attaches only its milligram content, and the arithmetic above transfers milligrams into units without any of the label's conditions.

MOTS-c dosage covers the other mitochondrial peptide on this site, the one with no label and no human trial. The general mixing procedure is documented on medibact.com's how to reconstitute peptides page; the reconstitution chart on this site lists concentrations for every vial size the calculators cover.

The insulin syringe units how-to explains the U-100 and U-40 scales and how a milligram figure becomes a syringe reading.

What this page does not do

This page reports what one label, two trials, one regulator action and the public web state about elamipretide dosing, each with its source and date, and converts the figures into syringe units for three research-vial sizes. It does not recommend an amount or a schedule, does not extend the label's Barth-syndrome indication to any other use, and does not present the vendor figures as anything other than what they are. The label's figures belong to the approved product; the tables are arithmetic, not a plan.

Sources and dates

Opened 2026-09-18: the Forzinity label on DailyMed (set id 146bf34c-76f2-48db-ac07-fb29cce2cd75, effective 2025-12-10), also read through the openFDA label endpoint; the DailyMed SPL search for elamipretide (one record); NCT03098797 and NCT03323749 on ClinicalTrials.gov; PMID 38602181 (Thompson et al., Genet Med 2024); the FDA's Drug Trials Snapshot for Forzinity and Stealth BioTherapeutics' approval announcement of 2025-09-19 as located by search; and a read of vendor and calculator pages for the figures in circulation. Corrections go to the contact page.

Frequently asked questions

What is the SS-31 dosage on the label?

The Forzinity label (elamipretide hydrochloride, Stealth BioTherapeutics, effective 2025-12-10) states 40 mg subcutaneously once daily for patients with Barth syndrome weighing at least 30 kg, and 20 mg once daily where eGFR is below 30 mL/min. The product is a solution of 280 mg in 3.5 mL, or 80 mg/mL, so the 40 mg dose is 0.5 mL, which is 50 units on a U-100 syringe. The label covers only Barth syndrome and only that solution.

What is the SS-31 peptide dosage chart?

There is one figure with a regulator behind it, 40 mg once daily, and one adjustment, 20 mg in severe renal impairment. The trials used the same 40 mg: TAZPOWER for 12 weeks and then up to 168 weeks, MMPOWER-3 for 24 weeks. The chart on this page is arithmetic, converting 5, 10, 20 and 40 mg into units at each research-vial size; the 5 and 10 mg columns are vendor figures with no source, included because they are what people search.

How many units is 40 mg of SS-31?

On the approved product, 50 units, because Forzinity is 80 mg/mL and 40 mg is 0.5 mL. From a research vial it depends on the concentration: 80 units at 50 mg/mL (a 50 mg vial with 1 mL), 160 units at 25 mg/mL, which is two syringes, and it cannot be drawn from a 5 mg or 10 mg vial at all, since the vial holds less than 40 mg. The table on this page has every combination of the three vial sizes and 1, 2 and 3 mL.

What is the SS-31 dosage protocol in the trials?

Every registered subcutaneous elamipretide trial read for this page used 40 mg once daily. TAZPOWER (NCT03098797, 12 participants) ran two 12-week periods in a crossover with a 4-week washout, then an open-label extension of up to 168 weeks. MMPOWER-3 (NCT03323749, 218 participants) ran 24 weeks and was terminated. Neither escalated, and neither used a loading phase; the figure was fixed from day one.

Where do the 5 to 10 mg figures come from?

From vendor and calculator pages read on 2026-09-18, not from any label or trial. No registered elamipretide study tested a dose in that range, and the approved product's lowest dose is the 20 mg renal adjustment. The pages that cite 5 to 10 mg do not cite a source, and this page reports the figures only so that a reader who meets them knows they are unsupported.

Is SS-31 the same thing as Forzinity?

The molecule is the same: SS-31 is the research-market name for elamipretide, the four-residue peptide Stealth BioTherapeutics developed and sells as Forzinity. The product is not the same: Forzinity is an approved 80 mg/mL solution in a labelled vial, and a research vial is a powder of stated milligram content and no other guarantee. The label's figures belong to the approved product; the arithmetic on this page is what transfers, and only the arithmetic.