According to Dr Nopadon, technically there are two approaches to use glutathione to whiten the skin. The first one is glutathione injection which lightens the skin by acting on the melanin, the primary determinant of skin colour. This, however, will take effect only when the substance is injected in a sufficiently large amount but will only render temporary effects. The second one is glutathione pills which still lack medical studies to back up its efficacy.