Interesting study showing that the active ingredient in Retin-A (tretinoin) appears to be just as effective if you wash it off after 30 minutes, with much less irritation. Something else your dermatologist won't tell you.

http://www.ncbi.nlm.nih.gov/pubmed/23167277

J Dermatolog Treat. 2012 Nov 20. [Epub ahead of print]

Short contact therapy of acne with tretinoin.

Veraldi S, Barbareschi M, Benardon S, Schianchi R.

Source

University of Milan, I.R.C.C.S. Foundation, Ca Granda Ospedale Maggiore Policlinico, Department of Pathophysiology and Transplantation, Milan, milan, Italy.

Abstract

Abstract The most frequent side effect of topical retinoids is irritant contact dermatitis.It occurs in approximately 85% of patients;the percentage can reach up to 95% in patients treated with tretinoin.Severity of this dermatitis is moderate to severe in approximately 20% of patients.However, 15% of patients stop the treatment with tretinoin because of skin irritation.We used tretinoin as short contact therapy in mild to moderate acne, in order to try to reduce the incidence and severity of irritant contact dermatitis.We present the final results of a sponsor-free, pilot, open, multicentre study.Seventy-four patients were treated with 0.05% tretinoin cream.It was applied once daily for 30 minutes.Treatment duration ranged from 8 to 32 weeks (mean duration: 12 weeks).Acne severity and treatment efficacy were evaluated by means of the Global Acne Grading System. A significant clinical improvement (50% from baseline) was observed in 41 patients (55.4%). Thirteen patients (17.6%) developed a mild skin irritation. Four patients (5.4%) stopped the treatment because of severe skin irritation. Efficacy of tretinoin used as short contact therapy seems to be superimposable to that of tretinoin used according to standard modality.Tolerability of short contact therapy with tretinoin is very good.This tolerability allows a high adherence of patients to the treatment and it markedly improves compliance.