Retinol on Human Skin Aging in East Asian Descent

Inclusion Criteria: * able to provide written informed consent * older group: age between 50 and 75 years * young group: age 18 to 25 years * all four grandparents of Han Chinese, Japanese, Korean descent * body mass index within normal or overweight range * no history of weight loss of \>20 lbs within past 5 years Exclusion Criteria: * skin condition in the areas of skin biopsy that would obscure results of analysis * topical creams or treatment to arms 2 weeks prior to study baseline visit * individuals with known hypersensitivity to retinoid class of agents (older group only) * prior anti-aging treatments to arms including retinol, microdermabrasion within 2 weeks of baseline visit * prior laser therapy or surgical procedure to arms * prior radiation or other trauma (extensive burns or abrasions) to arm skin * hormone-based therapy within 4 weeks of enrollment