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 (50 mg Vial) Dosage Protocol
- Vial
- 50 mg SS-31
- Add diluent
- 3 mL
- Concentration
- 16.67 mg/mL
- 1 unit (U-100)
- 166.67 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) | 30 units (0.30 mL) |
| Weeks 3–8 | 10 mg (10,000 mcg) | 60 units (0.60 mL) |
Advanced / Aggressive Approach
| Week | Daily Dose (mg) | Units (per injection) (mL) |
|---|---|---|
| Weeks 1–2 | 5 mg (5000 mcg) | 30 units (0.30 mL) |
| Weeks 3–4 | 10 mg (10,000 mcg) | 60 units (0.60 mL) |
| Weeks 5–8 | 15 mg (15,000 mcg) | 90 units (0.90 mL) |
| Optional Weeks 9–12 | 20 mg (20,000 mcg) | Split: 2 × 60 units (0.60 mL each) |
How to mix
- Draw 3.0 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
- Published human research does not support one universal SS-31 peptide dosage. Investigators selected different routes, durations, populations, and endpoints for different questions.
- Heart failure: PROGRESS-HF compared 4 mg and 40 mg subcutaneous elamipretide once daily for 28 days. The study did not show a significant improvement in its primary cardiac-structure outcomes.
- Primary mitochondrial myopathy: MMPOWER-2 evaluated 40 mg subcutaneously once daily for four weeks. Its primary six-minute-walk comparison was not statistically significant, although selected patient-reported outcomes favored elamipretide.
- Longer myopathy research: MMPOWER-3 used 40 mg once daily for 24 weeks and did not meet its primary efficacy endpoints.
- Barth syndrome: TAZPOWER used 40 mg once daily. The randomized crossover phase did not meet its primary endpoints, while longer open-label follow-up reported improvements that must be interpreted with the study design in view.
- Other routes and tissues: An acute heart-failure study used intravenous infusion rather than a daily subcutaneous vial protocol, while ReCLAIM and ReCLAIM-2 examined retinal disease under study-specific procedures.
- These trial designs provide clinical context, but none converts directly into the educational 50 mg vial schedule shown above.
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