Carotenoid (carotene pigment) found in plants, algae, and fish, particularly salmon, that functions as a potent antioxidant.  Research also suggests that astaxanthin may be able to prevent the oxidative damage to skin after exposure to UVA radiation. 
- Kleinová M, Hewitt M, Brezová V, Madden J, Cronin M, Valko M. Antioxidant properties of carotenoids: QSAR prediction of their redox potentials. Gen Physiol Biophys..2007;26(2):97-103.
- Niwano T, Terazawa S, Nakajima H, Wakabayashi Y, Imokawa G. Astaxanthin and withaferin A block paracrine cytokine interactions between UVB-exposed human keratinocytes and human melanocytes via the attenuation of endothelin-1 secretion and its downstream intracellular signaling. Cytokine.. 2015;72(2):184-97.