Astaxanthin is a member of the carotenoid family of phytonutrients. It is classified as a xanthophyll, which means "yellow leaves".
Like many carotenoids, it is fat-soluble, however it does not convert to Vitamin A (retinol) in the human body.
Astaxanthin shows antioxidant capacity 10 times stronger than other carotenoids and is a natural internal sunscreen that protects skin from sun damage and discoloration.
It can be found in microalgae, yeast, salmon, trout, krill, shrimp, crayfish and other crustaceans.
Because astaxanthin is lipid-soluble, your body will absorb more if you enjoy foods containing astaxanthin with some healthy fat.
Guerin M, Huntley ME, Olaizola M. Haematococcus astaxanthin: applications for human health and nutrition. Trends Biotechnol. 2003 May;21(5):210-6.