Shining a Light on UV-A1 Skin Damage

Suncreens may not provide enough protection for some forms of UV light

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Doctors have been warning us about the risks of sun exposure for years, and a new study shines a light on just how quickly you can get burned.

Individuals in this new study showed skin damage after just two exposures to ultraviolet A1 (UV-A1) light equal to a total of four hours of strong sun exposure.

Tan skin failed to provide any additional protection to UV-A1 light.

Clothing may not provide adequate protection from midday UV-A1 rays.

"Wear sun protection even on cloudy days."

This study was led by Frank Wang, MD, of the Department of Dermatology at the University of Michigan Medical School in Ann Arbor.

A total of 22 participants ranging in age from 22 to 61 years were exposed, up to four times, with a dose of UV-A1 radiation equal to two hours of strong sun exposure. Doses were administered to a small area of the individuals buttocks.

One day after exposure, the researchers measured changes in skin pigmentation before removing a small piece of skin to determine which genes had been changed by the light exposure.

The researchers were concerned that most available sunscreens are not as effective as they should be to UV-A1 Rays. They set out to show that even low-level exposure to the UV-A1 component of sunlight causes skin to look old, wrinkle and sag.

The researchers administered a single dose to 10 individuals, which resulted in no damage but did cause a noticeable darkening of the skin.

An additional 12 participants received four individual doses a day. Beginning with the second exposure, damage could be measured by the breakdown of collagen, a protein found in the skin.

Each additional exposure resulted in more darkening of the skin and further breakdown of collagen. The tanned skin did not provide additional protection from the UV-A1 rays.

The researchers believe that despite a generally high acceptance and understanding of the health risks associated with UV-A1 rays in sunlight, manufacturers of sunscreen offer few ingredients that provide adequate protection. Utraviolet (UV) light is found in sunlight and can cause mild to severe sun damge. One type of UV light called UV-A1 does not filtered out completely through window glass or clothing.

This study was published December 4 in JAMA Dermatology.

This research was supported by the National Institutes of Health.

No conflicts of interest were reported.

Review Date: 
December 5, 2013
Last Updated:
December 30, 2013