Astaxanthin is a powerful antioxidant that belongs to the carotenoid family. Carotenoids are coloured plant pigments that give fruits and vegetables their colours. Many carotenoids help to protect human cells from free radicals. Astaxanthin has been known to help prevent low-density lipoprotein oxidation in human blood and to possibly enhance the immune system. Astaxanthin is derived from marine algae and is related to beta carotene, but is more powerful than its relative at neutralizing singlet oxygen. Astaxanthin may also be able to decrease arterial blood pressure and help protect against damage caused by stroke. It is also believed to help improve memory in vascular dementia.