Meso-astaxanthin is one of three naturally occurring optical isomers of astaxanthin. Astaxanthins are a group of compounds providing red pigmentation in trout, salmon, lobster, shrimp and other sea creatures. Synthetic astraxanthins and biomass containing astraxanthins are used as feed additives in commercial fishing operations to ensure redness of the flesh. Astaxanthins as a group also exhibit antioxidant properties and are marketed in a number of nutriceutical products for human consumption. Isomers astaxanthin including meso-astaxanthin has demonstrated the ability to slow the growth of colon cancer cells in vitro.

(R, R)-astaxanthin is the naturally occurring enantiomer of astaxanthin and can be isolated from the yeast Phaffia rhodozyma and from Antarctic krill. Biomass of killed dead Phaffia rhodozyma is fed to salmon and trout to ensure red flesh pigmentation due to its high content of assorted astaxanthins. Astaxanthin and its stereoisomers have demonstrated the ability to inhibit the growth of colon cancer cells in-vitro.