Astaxanthin (AX) is a red carotenoid widely distributed in nature and possesses excellent antioxidant activity by quenching singlet oxygen and inhibiting lipid peroxidation. Recently, numerous biological activities of AX are reported. AX has been used for health supplements and cosmetics and is receiving increasing attention for complementary and alternative medicine. In this paper, we would like to clarify aspects of AX by presenting the origin, chemical properties, comparison with other carotenoids. Furthermore, we report the results of in vitro, in vivo analysis and clinical studies related to anti-lipid peroxidation, anti-inflammatory effects, blood flow improvement, effects on metabolic syndrome, anti-eye fatigue, effects on Helicobacter pylori, improved lipid metabolism, muscle endurance, effects on skin health, male infertility, pharmacokinetics, and safety.

A long-term safety study was conducted with astaxanthin derived from Haematococcus pluvialis algae extract. Fifteen healthy volunteers took 9 mg of astaxanthin daily for 12 weeks. Physiological (including doctor’s consultation), haematological, biochemical, and urinary markers were examined at weeks 0, 4, 8 and 12. No adverse effects or clinical changes were observed throughout the test period. It was concluded that a healthy adult can consume 9 mg of astaxanthin derived from Haematococcus pluvialis algae extract for 12 weeks without any safety concern.