But when it comes to understanding precisely how HRT affects the skin, the jury is still out. Logically, hormone therapy may be more capable of preventing skin aging in the first place than in repairing damage once it has occurred, but two new studies offer intriguing insights regarding approaches that may or may not work.
A downhill slopeWhile not going so far as to conclude that earlier HRT can offer skin benefits, one study failed to show benefits from HRT once women are several years past menopause.1
The study, said to be the largest randomized controlled trial studying the effects of HRT on the skin, randomized 485 subjects into one of three arms: a placebo group of 165 subjects; a group receiving 1 mg continuous combined norethindrone acetate and 5 microg ethinyl estradiol (162 subjects); and a group receiving 1 mg norethindrone acetate and 10 microg ethinyl estradiol (158 subjects).
Investigator global assessments looking at skin texture, dryness laxity, sagging and wrinkle depth after 48 weeks found no statistically significant differences between the groups receiving hormones and those receiving placebo.
One big difference between this study and earlier research showing skin improvement with hormone therapy was a lower dosage of estrogen, which was used to better reflect the levels that doctors are currently using, says Tania Phillips, M.D., the lead author on the study and clinical professor of dermatology at the Boston University School of Medicine.
"A lot of previous studies looking at estrogen and the skin have used far higher doses of estrogen, but there are now concerns about those higher levels and we wanted to use the standard doses that are commonly used in clinical practice nowadays."
In addition, since the subject selection didn't specify that participants be any particular number of years past menopause, the majority of women enrolled in the study wound up being as far as five to seven years past menopause.
"Marginally significant" improvements were reported in a small subgroup analysis of women who were less than 24 months postmenopausal, however, and Dr. Phillips suggests that further studies focusing on that group may show better results.
Earlier administration of hormone replacement therapy may be safer anyway, she notes.
"One of the big criticisms with the Women's Health Initiative trial was that the hormone replacement was given to older women who were many years postmenopausal and had other risk factors. Recent data suggests that if given for a relatively short period for menopausal symptoms, they're probably safe. Whether this will have beneficial effects on the skin, needs to be examined further." For the time being, however, there is not enough data to support the use of low-dose systemic estrogens for the treatment of skin aging.