Alpha hydroxy acid containing products are now widely used as cosmetics or skin protectives because it is believed to have a favorable effect against the aging process of skin.

The study aimed to find the effects of AHAs (glycolic acid, lactic acid) on the skin of hairless mice.

Glycolic acid (10 %, pH 3.9), lactic acid (10 %, pH 6.0) and vehicle control were applied topically to the back skin of hairless mice for two weeks. The thickness of the skin was measured by histometric analysis in addition to Masson-trichrome staining, immunohistochemical staining for TGF-beta and a Northern blot assay for pro α-l(I) collagen mRNA.

The change of the skin after topical treatment showed decreased mean epidermal thickness in the AHAs treated group, but the thickness of the dermis increased greatly compare to the controls (glycolic acid > lactic acid > control). Staining with Massontrichrome and TGF-beta showed a relatively increased expression in the AHAs treated specimens. These effects were correlated to the increased expression of pro a-1(I) collagen mR- NA from glycolic acid treated skin.

It is suggested that the favorable effects of AHAs treatment are achieved by increased dermal thickness associated with prominent collagen synthesis.