Sixteen women with idiopathic melasma were randomly assigned to apply 5% ascorbic acid cream on one side of the face and 4% hydroquinone cream on the other side, each night for 16 weeks. Sunscreen was applied daily throughout the study. The best subjective improvement was reported on the hydroquinone side, with 93% good and excellent results, compared with 62.5% on the ascorbic acid side (p < 0.05). However, colorimetric measures showed no significant difference between treatments. Side effects (mainly skin irritation) occurred in 68.7% of patients on the side where hydroquinone was applied and in 6.2% of cases on the side treated with ascorbic acid.

Comment: Melasma is a dark pigmentation of the skin that occurs on sun-exposed areas of the face. It is particularly common in pregnant women and in women taking oral contraceptives or hormone-replacement therapy during menopause. Hydroquinone is a bleaching agent that is effective in some cases. Tretinoin cream, and in some cases topical steroids or chemical peels, are also used. The results of the present study suggest that topical ascorbic acid cream is a safe and effective alternative to conventional treatments. Although ascorbic acid cream was somewhat less effective than hydroquinone, it was better tolerated, and may therefore be considered as a first line therapy for patients wishing to try the safest treatments first.

Espinal-Perez LE, et al. A double-blind randomized trial of 5% ascorbic acid vs. 4% hydroquinone in melasma. Int J Dermatol 2004;43:604-607.