Abstract Astaxanthin is a xanthophyll carotenoid with unique membrane-spanning anti-oxidative and anti-inflammatory activity. It penetrates the blood-retinal barrier to protect ocular tissues, enhance microcirculation, alleviate visual fatigue, and delay age-related macular degeneration. Cardiovascular benefits include reduction of lipid peroxidation, improvement of endothelial function, favorable modulation of blood lipids, and increased cerebral blood flow, supporting both heart and brain health.In reproductive health, clinical trials demonstrate improved sperm motility, morphology, and pregnancy outcomes, alongside ovarian protection and folliculo-genesis support.For skin, Astaxanthin reduces UV-induced oxidative stress and collagen degradation, improving hydration, elasticity, and pigmentation. It further acts as an immune-nutrient, enhancing NK cell activity, secretory IgA, and reducing NF-κB–mediated inflammation. Clinical evidence supports safe long-term use at 8-16 mg/day. Collectively, Astaxanthin represents a broad-spectrum nutritional intervention across ocular, cardiovascular, reproductive, skin, and immune systems, particularly for populations under oxidative stress.