Tetrahydrocurcumin (THC), as the active and main metabolite of curcumin produced in the body, is hydrogenated from curcumin isolated from the rhizome of the ginger plant Curcuma longa. Tetrahydrocurcumin is the main whitening active ingredient in natural turmeric root extract. It not only has the strongest tyrosinase inhibitory activity, but also has excellent chemical stability and appears as an odorless white powder, thus overcoming the problem of Ordinary turmeric extract is chemically unstable and easily stains the skin.