Topical tretinoin for treating photoaging: A systematic review of randomized controlled trials

Background: Aging, an inevitable and continuous process in one s lifetime, has all along been a focus of interest, especially for women, yet photoaging treatment to slow the process remains challenging. Recent studies have demonstrated the potency of topical tretinoin in the treatment of photoaging. Tretinoin, a metabolite of retinoids, shows prominent efficacy to regulate proliferation and differentiation of epidermal cells and induce new collagen formation. Objective: This review aims to study the current evidence on topical tretinoin for photoaging treatment. Methods: A systematic search of the literature was performed from Medline, Cochrane Central, Embase, and PubMed databases for published articles in the past 20 years. Only randomized controlled trials investigating tretinoin for photoaging treatment were included in our review. Results: A total of 180 studies were initially examined, of which 7 randomized controlled trials were included in this review. Four studies included only women as their participants, while the rest demonstrated women as their majority subjects. All studies that indicated topical tretinoin were safe and well tolerated in all patients. Topical tretinoin dosage varied from 0.025% to 5% while duration of treatment ranged from 3 months up to 24 months. With regard to efficacy, all studies consistently reported that topical tretinoin was efficacious in improving clinical appearance of photoaging in terms of wrinkling, mottled hyperpigmentation, sallowness, and lentigines as early as 1 month and lasted after 24 months. Limitations: Different tretinoin formulas used, different outcome parameters, and limited recent studies on topical tretinoin cause lack of uniformity in the evidences. Conclusion: Topical tretinoin is a safe and effective therapeutic modality for long-Term treatment of photoaging. Further research is required to compare dose-ranging topical tretinoin to other agents to provide the best treatment strategy for photoaged skin.