The study subjects were healthy non-smoking male volunteers aged 1933 years with no severe diseases or malabsorption. The study was a randomized doubleblind trial based on comparison of two parallel identically sized groups; the intervention group received 4 mg of astaxanthin (Astaxin, AstaReal AB, Sweden) capsules twice per day (N=20) and the placebo group two identical-looking placebo capsules (microcrystalline cellulose) (N=20).