Table 3.

Overview of studies involving 6 months’ tretinoin treatment

Reference	Study design	Duration	No. of patients	Observations and Inferences
Leyden et al (1989)	Randomized, double-blind 0.05% tretinoin cream vs vehicle control	6 months	30	Improvement in fine wrinkling, coarse wrinkling, sallowness and hyperpigmentation
Caputo et al (1990)	Dose escalating study tretinoin cream 0.01% in the 1st month, 0.025% in the 2nd month, 0.05% for next 4 months	6 months	89	Improvement in fine and coarse wrinkling, mottled hyperpigmentation, skin texture and laxity
Weinstein et al (1991)	Double-blind tretinoin emollient cream 0.05% and 0.01% vs vehicle	6 months	251	Significant improvement in fine wrinkling, mottled hyperpigmentation, roughness, laxity, epidermal thickness, in group treated with 0.05% tretinoin as compared with 0.01% and vehicle group Dose-dependant responses were observed No effect was seen in dermal thickness, collagen regeneration, reversal of keratinocytic atypia
Bhawan et al (1991)	Randomized, Double-blind tretinoin emollient cream 0.001%, 0.01% and 0.05% vs vehicle	6 months	533	Significant improvement in fine wrinkling, mottled hyperpigmentation, roughness, epidermal thickness, in group treated with 0.05% tretinoin as compared with 0.01%, 0.001% and vehicle group Dose-dependant responses were observed Vehicle-treated group showed some improvement
Olsen et al (1992)	Same as in case of Bhawan et al (1991)	6 months	296	Same as in case of Bhawan et al (1991)