SS-31

Elamipretide · Forzinity · not tier-graded · Moderate evidence

The most scientifically serious “longevity” peptide, yet it has mostly failed human trials outside one rare disease.

Dr. Tatem’s take

Not given a tier letter. His deep dive calls it the most scientifically serious longevity peptide, but notes it has largely failed in humans except for Barth syndrome, and that gray-market doses are far below trial doses.

Benefits

• Improved muscle strength in Barth syndrome (a rare mitochondrial disease).

Risks

• Injection-site reactions in essentially everyone.
• Serious allergic reactions; eosinophilia.

Dosing protocols (informational, labeled by evidence)

• Clinical trial / label: FDA label – Forzinity (Barth syndrome) — 40 mg (20 mg if eGFR <30), SubQ only, Once daily, Chronic
• Clinical trial / label: MMPOWER-3 (mitochondrial myopathy) — 40 mg, SubQ, Daily, 24 wk
• Community (bro science): Gray-market use — 2–10 mg, SubQ, Daily, Varies

Status: FDA accelerated approval (Sept 2025) as Forzinity for Barth syndrome only. Named in August 2026 warning letters to research-peptide sellers.

Grade and commentary: Dr. Alex Tatem. Watch: SS-31: The Most Controversial Anti-Aging Peptide Ever Made. Subscribe: @DrAlexTatem.