Astaxanthin is a naturally occurring carotenoid that, due to its unique structure, performs an important role in cellular free radical protection and healthy immune system responses.* NOW® Astaxanthin is derived from non-GMO Haematococcus pluvialis microalgae and has naturally occurring lutein, canthaxanthin, and beta-carotene. This extra strength product has over twice the astaxanthin (10 mg per softgel) than our regular strength product (4 mg per softgel). NOW uses AstaReal® Astaxanthin, the most studied brand of natural astaxanthin from algae which is supported by more than 150 studies, including more than 70 human clinical studies.