BACKGROUND: Salicylic acid (SA) and retinoids, tretinoin (all-trans retinoic 
acid [ATRA]), and retinol (all-trans retinol) are widely used as topical agents 
for the improvement of photodamage and acne vulgaris. They can be used in daily 
take-home products or as part of an in-office procedure, combining the benefits 
of a keratolytic (SA) and a retinoid.
OBJECTIVE: The objective of this research was to compare the efficacy for 
ameliorating photodamage of topical tretinoin (0.25%) and retinol (0.25%) to 
baseline and with each other when applied after a 30% salicylic acid peel on 
human facial skin.
METHODS: Twenty female subjects received a full face 30% SA peel followed by the 
overnight application of tretinoin to a 1 randomized half-face and retinol to 
the opposite side (split-face study). The identical procedure was repeated at 
week 2. Double-blinded subject and investigator assessments of the results were 
captured at weeks 2 and 4.
RESULTS: By investigator evaluation, both peeling regimens were effective in 
improving photodamage parameters compared to baseline. (ATRA P-values at week 4 
were: P=.00008 texture, P=.00013 roughness, P=.00221 pores, P=.00098 dryness, 
P=.02770 erythema, and P=.00008 overall appearance. Retinol P-values at week 4 
were: P=.00019 texture, P=.00053 roughness, P=.00221 pores, P=.00147 dryness, 
P=.02770 erythema, and P=.0043 overall appearance.) By subject self-assessment 
compared with baseline, both tretinoin and retinol were effective in improving 
overall appearance (ATRA P=.0229 and retinol P=.0190). By investigator 
evaluation comparing tretinoin with retinol, tretinoin was slightly better than 
retinol at week 4 in improving texture P=.00506, roughness P=.01171, and overall 
appearance P=.00506. By subject self-assessment comparing tretinoin with 
retinol, there was no difference in overall appearance (ATRA P=.2367 and retinol 
P=.3613).
CONCLUSION: Either topical tretinoin (0.25%) or retinol (0.25%) can be used 
safely and effectively when applied in office immediately after SA peeling to 
ameliorate signs of photoaging.