In addition to its effect on color, one of the most important properties of astaxanthin is its antioxidant properties which have been reported to surpass those of β-carotene (from which vitamin A is derived) or even α-tocopherol (vitamin E). It is claimed to possess as much as 10 times the antioxidant potential of other carotenoids such as zeaxanthin, lutein, canthaxantin, and β-carotene; and 100 times more that α-tocopherol. However, other sources suggest astaxanthin has slightly lower antioxidant activity than other carotenoids. Thus, caution must be observed when studying and comparing the antioxidant activity of the various carotenoids since results will be dependent on the experimental conditions under which the assays are performed. In spite of the variability in assessed antioxidant potential astaxanthin is a potent antioxidant and this activity of astaxanthin has been attributed with the potential to protect against a wide range of ailments such as cardiovascular disease, numerous types of cancer and some diseases of the immune system.