Tolerance of topical retinaldehyde in humans

Background: Retinaldehyde (RAL) has been used as a topical agent in many co untries since 1994. Aim: To review current data on the tolerance of retinal dehyde and to report the results of a long-term pilot study. Methods: Data from published and on-file studies have been compiled. Forty-five patients who had applied RAL on the face for 12-89 months were specifically examined for side-effects. Results: Studies in humans demonstrated an excellent tol erance of topical RAL on human skin. It was much better tolerated than reti noic acid and could be used even on sensitive facial skin. It does not have phototoxic, or photo-allergic properties. No side-effects were associated with long-term use. Conclusion: Current data indicate a good topical tolera nce of RAL in humans.