SS-31 (Elamipretide)
Also called Forzinity; Bendavia
A four-amino-acid peptide that targets mitochondria. In September 2025 the FDA granted accelerated approval to Forzinity (elamipretide) for muscle strength in Barth syndrome, a rare genetic disorder. That is not approval for fatigue, weight loss or anti-aging.
Overview
What it is
A small peptide that binds cardiolipin, a lipid in the inner mitochondrial membrane that supports energy (ATP) production.
How it works
By stabilizing cardiolipin, it is intended to improve mitochondrial structure and function.
What the research shows
Forzinity's approval relied on improved knee-extensor strength in a small Barth syndrome program; the randomized portion did not improve walking distance or fatigue. The MMPOWER-3 trial in 218 people with mitochondrial myopathy found no significant benefit in walking distance or fatigue. A 2021 study in older adults found a short-lived rise in muscle ATP capacity after one infusion, without improved muscle fatigue resistance.
Studied for
- Barth syndrome muscle strengthaccelerated approval
- Primary mitochondrial myopathyphase 3, negative
- Muscle energy in older adultssingle-dose study
Safety and regulatory status
Safety and side effects
Injection-site reactions are the most common side effect; serious allergic reactions have been reported. Severe kidney impairment may require adjustment. It contains benzyl alcohol and must not be used in newborns.
Regulatory status
Forzinity is FDA approved (accelerated) only for Barth syndrome in patients weighing at least 30 kg. Continued approval may depend on a confirmatory trial. Research "SS-31" products are not approved.
Mixing and dosing reference
Reference information only. Read before using this section.
SS-31 (10 mg Vial) Dosage Protocol
- Vial
- 10 mg SS-31
- Add diluent
- 1 mL
- Concentration
- 10 mg/mL
- 1 unit (U-100)
- 100 mcg in 0.01 mL
- Route
- Subcutaneous
- Typical range
- 5–10 mg once daily (gradual titration); advanced protocols may reach 15–20 mg/day under supervision.
Standard / Gradual Approach
| Week | Daily Dose (mg) | Units (per injection) (mL) |
|---|---|---|
| Weeks 1–2 | 5 mg (5000 mcg) | 50 units (0.50 mL) |
| Weeks 3–8 | 10 mg (10,000 mcg) | 100 units (1.0 mL) |
Advanced / Aggressive Approach
| Week | Daily Dose (mg) | Units (per injection) (mL) |
|---|---|---|
| Weeks 1–2 | 5 mg (5000 mcg) | 50 units (0.50 mL) |
| Weeks 3–4 | 10 mg (10,000 mcg) | 100 units (1.0 mL) |
| Weeks 5–8 | 15 mg (15,000 mcg) | Split: 2 × 75 units (0.75 mL each) |
| Optional Weeks 9–12 | 20 mg (20,000 mcg) | Split: 2 × 100 units (1.0 mL each) |
How to mix
- Draw 1.0 mL bacteriostatic water with a sterile syringe.
- Inject slowly down the vial wall; avoid vigorous shaking to prevent foaming.
- Gently swirl/roll until fully dissolved (clear solution).
- Label with reconstitution date and refrigerate at 2–8 °C (35.6–46.4 °F), protected from light; follow product-specific use-by and sterile-handling requirements.
Dosing details
- The human research record is broader than a single SS-31 dosage per day. Investigators have used subcutaneous dosing and short intravenous infusions across different conditions. Results have varied by population and endpoint.
- PROGRESS-HF randomized participants with heart failure and reduced ejection fraction to 4 mg, 40 mg, or placebo once daily for 28 days. The trial reported no significant improvement in left ventricular end-systolic volume, end-diastolic volume, or ejection fraction.
- MMPOWER-2 used 40 mg once daily for four weeks in primary mitochondrial myopathy. The prespecified six-minute walk comparison did not reach statistical significance.
- MMPOWER-3 used 40 mg once daily for 24 weeks in a larger primary mitochondrial myopathy trial. Primary six-minute walk and fatigue endpoints were not met.
- TAZPOWER used 40 mg once daily in Barth syndrome. Interpretation requires separating the randomized crossover phase from longer open-label follow-up.
- A heart failure study evaluated short intravenous elamipretide infusions rather than a daily subcutaneous vial protocol. ReCLAIM and ReCLAIM-2 examined elamipretide in dry age-related macular degeneration using study-specific procedures and endpoints. These studies help define the evidence base, but their dosing formats should not be converted into a 10 mg vial schedule.
Protocol source: PeptideDosages.com
Common questions
Is SS-31 FDA approved?
Only Forzinity, for Barth syndrome.
Can it help with weight loss?
The trials did not study weight loss.
Does more ATP mean more energy?
Not necessarily; the older-adult study saw no fatigue improvement.
Related in Healthy Aging
Sources and further reading (6)
- FDA. Drug Trials Snapshots: Forzinity, Sept 2025.
- DailyMed. Forzinity prescribing information.
- Karaa A, et al. Elamipretide in primary mitochondrial myopathy (MMPOWER-3). Neurology, 2023.
- Roshanravan B, et al. Elamipretide and mitochondrial ATP production in older adults. PLoS One, 2021.
- MedlinePlus Genetics. Barth syndrome.
- Source summary: PeptideDosages.com research overview (rewritten for NVO).
Laboratory research material: SS-31 Research Use Only