Astaxanthin

Astaxanthin is a red-pink pigment (a ketocarotenoid). It is made mainly by a microalga (Haematococcus pluvialis). It then travels up the food chain into crustaceans, salmon, and trout, giving them their color. Its structure is special. It has a long polyene chain with carbonyl and hydroxyl groups on both rings. That lets it stretch across a full cell membrane and neutralize singlet oxygen and free radicals. In lab tests, it quenches singlet oxygen better than many other carotenoids, including β-carotene. And unlike some antioxidants, it does not flip into a pro-oxidant at high doses. Its proposed longevity mechanisms include switching on Nrf2, blocking NF-κB, protecting mitochondria, and tuning inflammatory signals. Rodent studies show better oxidative stress, immunity, and some heart markers. Human trials are small and short. They report modest effects on fat-oxidation markers, skin aging, exercise muscle damage, and inflammation. One nuance: synthetic astaxanthin (common in fish farming) differs from natural algal forms in chemistry. That may change how well you absorb it. Evidence for a direct human longevity benefit is still preliminary.

Last reviewed: June 22, 2026

This definition is educational and is not medical advice, a diagnosis, or treatment. Talk to a doctor about any health decisions. Read our full medical disclaimer