Label (Barth syndrome)
Label- Dose
- 40 mg
- How often
- Once daily
- How long
- Ongoing
Flat dose for people 30 kg and up, not per kg. 20 mg if kidney function (eGFR) is under 30 and not on dialysis; no dose set for dialysis.
Approved drugMitochondria-targeted peptide
SS-31
Elamipretide (Forzinity)
- Common dose
- Label 40 mg; community 1–10 mg daily
- Cycle
- 8 weeks on, 4 off
- Vial sizes
- 10, 50 mg
- Typical draw
- 50 units10 mg with 1 mL, 5 mg
A four-amino-acid peptide that concentrates in the inner mitochondrial membrane and binds cardiolipin, supporting energy production.
Evidence. FDA accelerated approval in 2025 as Forzinity, for muscle strength in Barth syndrome (a rare mitochondrial disease). Other uses are unproven.
Status
- Approval
- Approved in the US in 2025 as Forzinity (accelerated approval), to improve muscle strength in Barth syndrome patients weighing at least 30 kg.
- Sport (WADA 2026)
- Not banned in sportNot named on the 2026 list. As an FDA-approved drug since 2025, it is not an unapproved (S0) substance.
Sport status follows the WADA Prohibited List in force since January 1, 2026; athletes should confirm with their anti-doping organization. Checked October 5, 2026.
Protocol
Label
Forzinity, Barth syndrome, 30 kg and up
40 mg once daily; 20 mg if eGFR is under 30 and not on dialysis. The label sets no dose for people on dialysis.
Community
1–10 mg once daily for general use.
- Frequency
- Once daily
- Route
- Subcutaneous injection
- Cycle
- Label: continuous. Community: 4–12 week courses.
8 weeks on, 4 off, shown over 26 weeks
Common protocols
The ways SS-31 is most often run, each tagged with where it comes from.
Community course
Community- Dose
- 4–6 mg (range 1–10 mg)
- How often
- Once daily
- How long
- 3–12 weeks
Common in ‘mito stack’ guides, sometimes tapering to 2–3 times a week. No trial supports these doses.
Draw 40–60 units10 mg + 1 mL
Taking it
Where it goes
Subcutaneous in the abdomen (at least 2 inches from the navel) or outer thigh, rotating the site daily. Avoid tender, bruised, red or hard skin, scars and stretch marks (label).
If you miss a dose
Label: “If a dose is missed, skip the dose and take the next dose … at the scheduled time. Do not take a double dose.”
What to expect
- From the first doses
Injection-site reactions in nearly everyone: redness in 100% vs 25% on placebo.
Label - Weeks 1–12
In the randomized phase, strength barely changed (median +4 newtons vs -5 on placebo); walking and fatigue goals were missed.
Label - Extension weeks 12–168
Knee strength rose a median 34 newtons by extension week 12 and 68 by week 24 (baseline about 124); it was +63 at week 168.
Label - Around 3 months
Eosinophil (a white blood cell) counts often rise, peaking near day 90 with no symptoms, then fall back to baseline after 6–12 months or after stopping.
Label
Side effects and what to do
Injection-site redness (label: 100% vs 25% placebo)
Expected. Rotate sites daily; the label suggests steroid creams or oral antihistamines.
Injection-site pain (label: 75% vs 42%)
Rotate sites; don’t inject into tender, bruised or hard skin.
Itching and hardening at the site (label: 67% each vs 17%)
Skip hardened spots. Steroid cream or an antihistamine can ease itch.
Bruising or hives at the site (label: 25% each vs 0%)
Usually local. Hives spreading beyond the site may be an allergy; stop and get help.
Serious allergic reaction (label warning)
Rash, skin lesions or breathing symptoms. Stop and get emergency care; the label says to discontinue.
Stop and get medical help
Stop and get emergency care for widespread hives, swelling of the face or throat, wheezing or trouble breathing. The label reports serious allergic reactions needing emergency treatment.
Tracking and pairing
Worth tracking
- Signs of allergic reaction (label)
- Injection-site skin changes
- Kidney function (eGFR), which sets the dose
- Eosinophil count (rose in trials; not a label requirement)
Human studies
5 key published human studies, with how many people took part. Animal studies aren’t listed here.
-
Missed both primary goals: 6-minute walk changed -3.2 m versus placebo (p=0.69), with no fatigue benefit; generally well tolerated.
- Design
- Phase 3 randomized controlled trial (MMPOWER-3) in primary mitochondrial myopathy
- Dose
- 40 mg SC once daily
- Length
- 24 weeks
Karaa et al., Neurology 2023 (MMPOWER-3), PMID 37268435
-
No improvement in heart volumes or ejection fraction on MRI versus placebo; side effect rates were similar across groups.
- Design
- Phase 2 randomized controlled trial (PROGRESS-HF) in heart failure with reduced ejection fraction
- Dose
- 4 mg or 40 mg SC once daily
- Length
- 4 weeks
Butler et al., J Card Fail 2020 (PROGRESS-HF), PMID 32068002
-
6-minute walk was 19.8 m longer than on placebo but not significant (p=0.08); fatigue scores improved; injection-site reactions in 80%.
- Design
- Randomized, placebo-controlled crossover trial (MMPOWER-2) in primary mitochondrial myopathy
- Dose
- 40 mg SC once daily
- Length
- 4 weeks per period
Karaa et al., J Cachexia Sarcopenia Muscle 2020 (MMPOWER-2), PMID 32096613
-
No benefit in the randomized part; in the uncontrolled extension, 6-minute walk improved 95.9 m by week 36 (8 patients).
- Design
- Randomized crossover trial plus open-label extension (TAZPOWER) in Barth syndrome
- Dose
- 40 mg SC once daily
- Length
- 12 weeks per period, then a 36-week extension
Thompson et al., Genet Med 2021 (TAZPOWER), PMID 33077895
-
6-minute walk improved 96.1 m by week 168 in the 8 patients who stayed; injection-site reactions were the most common side effect.
- Design
- Open-label extension of TAZPOWER in Barth syndrome, no placebo
- Dose
- 40 mg SC once daily
- Length
- 168 weeks
Thompson et al., Genet Med 2024, PMID 38602181
Mixing your vial
| Vial | Water | Common dose | Draw | Strength | Action |
|---|---|---|---|---|---|
| 10 mg | 1 mL | 5 mg | 50 units (0.50 mL) | 10 mg/mL | |
| 50 mg | 5 mL | 5 mg | 50 units (0.50 mL) | 10 mg/mL |
Forzinity is a ready-made 80 mg/mL solution. Research vials are lyophilized powder.
Dose chart
Syringe units for common doses at different water volumes. Select a cell to open it in the calculator.
| Dose | Water added | ||
|---|---|---|---|
| 1 mL | 2 mL | 3 mL | |
| 1 mg | |||
| 2 mg | |||
| 4 mg | |||
| 5 mg | |||
| 6 mg | |||
| 10 mg | |||
| 25 mg | – | – | – |
| 40 mg | – | – | – |
U-100 insulin syringe: 100 units is 1 mL. Draws over 100 units show in mL. Faded values are under 2 units, which is hard to measure. Check that your vial holds the larger volumes.
Datasheet
- Half-life
- No reliable value has been published.
- Type
- Peptide, 4 amino acids
- Molecular weight
- 639.8 g/mol
- Formula
- C32H49N9O5
- Sequence
- r(Dmt)KF-NH2
- Storage before use
- The approved product is a ready solution (80 mg/mL vial), not powder. Refrigerate unopened vials at 2–8 °C (36–46 °F); do not freeze.
- After mixing or opening
- After first use, keep the vial in the fridge or at 20–25 °C (68–77 °F), and discard it 8 days after opening.
- Molecule: PubChem CID 11764719. r = D-arginine, Dmt = 2’,6’-dimethyltyrosine. The label’s MW of 749.2 is the trihydrochloride salt.
- Storage: Label Forzinity prescribing information, section 16 (FDA, 2025)
Cautions
- Injection-site reactions are the most common side effect (redness, itching, hardening).
- Serious allergic reactions are possible.
- Community doses have no trial support.
Questions
What is SS-31?
A four-amino-acid peptide that concentrates in the inner mitochondrial membrane and binds cardiolipin, supporting energy production.
Is SS-31 FDA-approved?
Approved in the US in 2025 as Forzinity (accelerated approval), to improve muscle strength in Barth syndrome patients weighing at least 30 kg.
What is the usual SS-31 dose?
From the label (Forzinity, Barth syndrome, 30 kg and up): 40 mg once daily; 20 mg if eGFR is under 30 and not on dialysis. The label sets no dose for people on dialysis. From community reports, not established: 1–10 mg once daily for general use. These are the amounts sources reference, not recommendations.
How much water do I mix SS-31 with?
There’s no single right amount, because the water only sets the strength. With 1 mL of bacteriostatic water in a 10 mg vial, the strength is 10 mg/mL, so 5 mg is 50 units on a U-100 insulin syringe. More water makes small doses easier to measure. The dose chart above shows other volumes.
How should SS-31 be stored?
The approved product is a ready solution (80 mg/mL vial), not powder. Refrigerate unopened vials at 2–8 °C (36–46 °F); do not freeze. After first use, keep the vial in the fridge or at 20–25 °C (68–77 °F), and discard it 8 days after opening.
Is SS-31 banned in sport?
No. Not named on the 2026 list. As an FDA-approved drug since 2025, it is not an unapproved (S0) substance.
Has SS-31 been studied in people?
Yes. The human studies section lists 5 published studies. The largest, from 2023, included 218 people. Missed both primary goals: 6-minute walk changed -3.2 m versus placebo (p=0.69), with no fatigue benefit; generally well tolerated.
Sources
- Forzinity (elamipretide) prescribing information (FDA)
For the protocol details
- Forzinity package insert, clinical studies section (Drugs.com)
Doses tagged Community come from public dosing guides and user reports, checked against at least two of them. Those sites aren’t named here because many of them sell peptides or earn commissions on them.