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.

Astaxanthin, a red carotenoid, has been known to possess excellent antioxidant activity and various biological activities, thereby attracting attention as a functional food material.The safety of astaxanthin administered orally has been demonstrated in human clinical studies for about ten years.In this review, we summarized the clinical studies related to safety, as well as studies on genotoxicity, and acute and subchronic toxicity, with a focus on AstaREAL, an astaxanthin product derived from Haematococcus pluvialis which has been reported in numerous human clinical studies to be safe and to have multiple health benefits.Furthermore, based on the latest research, we reviewed the effect of astaxanthin on drug-metabolizing enzymes involved in drug interactions, and concluded that the safety of H. pluvialis-derived astaxanthin, AstaREAL has been widely confirmed.