Is SS-31 safe?

Traditional antioxidants like vitamin C or E work by neutralizing free radicals after they are produced. SS-31 takes a fundamentally different approach — it stabilizes the mitochondrial membrane to prevent excessive ROS production in the first place. This upstream mechanism is why researchers consider it more promising than conventional antioxidant supplementation for mitochondrial dysfunction.

The pivotal phase III trial did not meet its primary endpoint (6-minute walk distance improvement) despite showing improvements in secondary endpoints like cardiac stroke volume and biomarkers. This is common in rare disease trials with small sample sizes and variable disease severity. The biological activity was real, but the trial design may not have captured it in the primary outcome.

Both target mitochondria but through completely different mechanisms. MOTS-c is a naturally occurring mitochondrial-derived peptide that activates AMPK signaling. SS-31 is a synthetic peptide that directly stabilizes the inner mitochondrial membrane. They represent complementary approaches to mitochondrial health and are sometimes discussed together in longevity circles.