Applying topical retinol to the skin appears to improve the wrinkles associated with natural aging and may help to promote the production of skin-building compounds, according to a report in the May issue of Archives of Dermatology.

The wrinkles and brown spots associated with aging appear first and most prominently on skin exposed to the sun, according to background information in the article.

"Human skin not exposed to the sun also ages but less dramatically," the authors write. "In intrinsic, natural or chronological aging, skin loses its youthful appearance by becoming thinner, laxer and more finely wrinkled. These changes are readily appreciated by inspecting the upper inner arm." Thinner skin results from a reduced production of the protein collagen and may slow wound healing, presenting a public health issue. "Safe and effective therapies to reverse the atrophy of natural skin aging do not exist currently," the authors note.

Reza Kafi, M.D., then of the University of Michigan Medical School, Ann Arbor, and now of Stanford Medical School, Palo Alto, Calif., and colleagues assessed the effectiveness of vitamin A (retinol) lotion in 36 elderly individuals (average age 87 years). Researchers applied a lotion containing 0.4 percent retinol to participants’ right or left upper inner arms, and lotion with no retinol to the other arm, up to three times a week for 24 weeks. Wrinkles, roughness and overall severity of aging were each graded on a scale from zero (none) to nine (severe) before treatment and two, four, eight, 16 and 24 weeks after beginning treatment. In addition, 4-millimeter biopsy specimens of skin were taken from both arms at the beginning and end of the 24-week treatment period.

A total of 23 individuals completed the full study and 13 withdrew from the study prior to completion. When the researchers included the individuals who had dropped out of the study by assuming their skin did not change after their last measurement, wrinkles, roughness and overall aging severity were all significantly reduced in the retinol-treated arm compared with the control arm. The skin biopsies revealed that the retinol increased the production of glycosaminoglycan and procollagen, structural components of the skin.

"Topical retinol improves fine wrinkles associated with natural aging," the authors conclude. "Significant induction of glycosaminoglycan, which is known to retain substantial water, and increased collagen production are most likely responsible for wrinkle effacement [reduction]. With greater skin matrix synthesis [production of compounds that form new skin], retinol-treated aged skin is more likely to withstand skin injury and ulcer formation along with improved appearance."