Dietary Supplement Nutricost Quality Guaranteed Third Party Tested Gluten-Free Product Non-gmo Product Nutricost Astaxanthin Capsules Astaxanthin is a naturally occurring antioxidant and carotenoid, found in certain algae and also causes the pink color in salmon, trout, lobster, shrimp, and other seafood. As an antioxidant, it is said to have many health benefits including heart and joint support. Nutricost Astaxanthin contains 4mg, 6mg, or 12mg of Astaxanthin per capsule and is always tested by independent Iso Accredited laboratories to ensure quality.