Complete depigmentation of the normal skin of adult male blacks was procured by the daily application for five to seven weeks of a formula consisting of 0.1% tretinoin, 5.0% hydroquinone, 0.1% dexamethasone, and hydrophilic ointment. Depigmentation was not attainable when any one of the components was omitted.
The formula was therapeutically effective in treatment of melasma, ephelides, and postinflammatory hyperpigmentation. Senile lentigines were resistant to this therapy.
Kligman AM, Willis I. A New Formula for Depigmenting Human Skin. Arch Dermatol. 1975;111(1):40-48. doi:10.1001/archderm.1975.01630130042004