D-penicillamine, a potent melanogenesis inhibitor, lacks any depigmenting effect on black guinea pig skin: the first randomized, evaluator-blinded, vehicle-controlled, in vivo study.

D-penicillamine is a melanogenesis inhibitor. This in vivo study on ten black guinea pigs using a 5% D-penicillamine ointment showed its lack of any skin-lightening effect. The potential reasons for this ineffectiveness are discussed in the paper, which could be very helpful for researchers exploring new skin-lightening agents.