Fucoxanthin is a carotenoid, with formula C42H58O6. It is found as an accessory pigment in the chloroplasts of brown algae and most other heterokonts, giving them a brown or olive-green color. Fucoxanthin absorbs light primarily in the blue-green to yellow-green part of the visible spectrum, peaking at around 510-525 nm by various estimates and absorbing significantly in the range of 450 to 540 nm. Some metabolic and nutritional studies carried out on rats and mice at Hokkaido University indicate that fucoxanthin promotes fat burning within fat cells in white adipose tissue by increasing the expression of thermogenin.[1]As of 2008, no human studies on fucoxanthin have been published, so it remains to be seen whether it is of any value in human obesity.
