Astaxanthin, unlike several carotenes and one other known carotenoid, is not converted to vitamin A (retinol) in the human body.
Like other carotenoids, astaxanthin has self-limited absorption orally and such low toxicity by mouth that no toxic syndrome is
known. In vitro, it is an antioxidant with a slightly lower antioxidant activity in some model systems than other carotenoids.
Astaxanthin can be used as a dietary supplement intended for human, animal, and aquaculture consumption.