Is it permissible to take pills that cleanse the liver and whiten the body with the intention of achieving both effects?

Body whitening falls into two categories: One is for medical reasons (the presence of more than one skin tone on the body), in which case treatment is permissible. The other is for cosmetic purposes, which is not permissible. As for treating melasma, it is permissible. If using a melasma treatment leads to body whitening, and there is an effective alternative medicine, then that alternative must be used. However, if the only available medicine is the one that whitens, then its use is permissible, as it is a byproduct of a legitimate treatment and not intended for its own sake.