This study was aimed to evaluate the inhibitory effect of astaxanthin on 7 types of CYP enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A4) by using human liver microsomes and to evaluate the inducing effect of astaxanthin on 3 types of CYP (CYP1A2, CYP2B6 and CYP3A4) by using cryopreserved human hepatocytes.Resuts indicated that astaxanthin does not inhibit CYP enzymes within the normal doses and astaxanthin does not induce CYP enzymes within the normal doses.

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.

An exploratory open-label human clinical study was performed in healthy adults with shoulder stiffness to evaluate the efficacy of Astaxanthin by means of measuring blood flow change in the shoulders and subjective questionnaires on physical conditions, including alleviation of stiffness before and after treatment. Two capsules containing 3 mg Astaxanthin each (6 mg in total) were administered once daily (6 mg a day) on days 1 to 28 (4 weeks) to 13 patients (3 men/10 women). All patients were assessed for efficacy and the study demonstrated significant improvements in physical conditions such as shoulder stiffness, physical fatigue, sense of mental irritation, sense of coldness in hands and feet, eye fatigue and eye bleariness. Significant increases of blood flow in shoulders were observed at the end of treatment using laser-doppler graphics. Blood tests conducted to confirm safety before and at the end of treatment showed no clinical differences, and no adverse side effects were reported. In conclusion, Astaxanthin appeared to safely alleviate stiff shoulders and improve other physical conditions during a 4-week open-label study.

Objectives: To study the effect of astaxanthin contained drink to skin conditionMethod: The study was conducted to the Japanese females between age over thirty to less than fifty , who had weakening of skin (including aging, sag and dry skin) and skin dullness. In order to conduct the objective evaluation, the comparison between the groups by the double-blind test was taken. Twenty of subjects were randomly allocated to the intake group of astaxanthin contained drink (astaxanthin 3mg contained) and the placebo group. After eight weeks intake of the drink, each group was evaluated with skin water contents, transepidermal water loss, skin elasticity, VISIA and skin texture etc.Result: In between the groups, the intake group of astaxanthin contained drink was greatly excellent in the categories of skin moisture, transepidermal water loss, skin elasticity , erythema dose and skin texture.Conclusion:Astaxanthin has protecting effect of skin barrier and is considered to increase the water retention capability to reduce skin dryness. Astaxanthin is also effective to erythema dose, skin elasticity and skin texture.　As no adverse events resulting from the test drink was seen, such food containing astaxanthin is considered as a safe and useful health functional food material to skin.