Astaxanthin, a substance in the carotenoid family, provides the pink color of salmon and many other sea creatures. Like other carotenoids, astaxanthin is a strong antioxidant. It has been advocated for treating or preventing a number of health conditions, but as yet none of these proposed uses is supported by meaningful scientific evidence.

Astaxanthin is not an essential nutrient. However, it is possible that increased intake of astaxanthin could provide health benefits.

Salmon is an excellent source of astaxanthin. A typical serving of Atlantic salmon provides approximately 1 mg of astaxanthin, while a similar serving of Pacific salmon might provide 4-5 mg. Krill oil is another good food source of astaxanthin.

When consistently exposed to high levels of ultraviolet light, the algae Haematococcus pluvialis produces very large quantities of astaxanthin, presumably to protect itself from injury. Haematococcus raised in this way is used as a commercial source of astaxanthin.