At the urging of Arandjel, I decided to take a look at estrogen as an anti-aging skin care ingredient. I’m confining my research to topical estrogen and what its positive effects – if any -- might be. For those interested in the broader topic of hormone replacement therapies, there’s a discussion thread led by Susan after my post on the Second Half of Your Life. Here I want to try to work out if the good imparted by topical estrogen outweighs the possible risks.

Estrogen and Skincare

The general theory is that postmenopausal women on estrogen replacement therapy develop fewer wrinkles and have better skin texture and elasticity than those not taking estrogen. So, it seems logical that topical application of estrogen should also be helpful. There are two ways to do this. One is with a topical estradiol or estriol cream. The other is with phytoestrogens, plant-derived ingredients that mimic human estrogens.

Does Estrogen Improve Skin?

Estradiol and estriol are typically used in gels to treat vaginal dryness in post menopausal women. As far as their success with dry, wrinkled skin is concerned there is one much-quoted study from the University of Vienna Medical School, Austria. The trial was conducted with 0.01% estradiol or 0.3% estriol on 59 postmenopausal women. After six months of treatment, a marked improvement in skin elasticity and firmness was noted; wrinkle depth and pore size decreased by over 60% in both estradiol and estriol groups. Skin moisture and collagen synthesis increased significantly.

However, other studies have not been so positive and in 2009, dermatologist Margaret E. Parsons, MD, FAAD from the University of California reviewed them and concluded that at best the results where mixed as to whether estrogen improves the appearance of the skin.

“Based on the research conducted thus far, it does not appear that topical or oral estrogens are a viable long-term solution for improving sun-damaged or aging skin,” said Dr. Parsons. “In my practice, I do not prescribe estrogens for skin rejuvenation because of the lack of consistent data to support their use and the known risks of prolonged estrogen therapy – including an increased risk of breast cancer.”

For example, one study examined whether low-dose hormone therapy improved aging skin in 485 women who were on average five years post-menopausal. The study concluded that estrogen supplementation did not provide any significant improvement in sun-damaged skin.

Could Other Factors Influence Estrogen's Effectiveness for Skin?

Timing might be a factor. In one study, using Premarin cream, researchers observed a trend, although not statistically significant, of improvement in the skin of women who were less than 24 months postmenopausal. Two other studies concluded that the use of topical estrogens, such as Premarin cream or topical estradiol gel, could decrease fine wrinkling, improve roughness of the skin and stimulate collagen synthesis. Yet another found local that estriol, when applied to abdominal skin for three weeks, thickened fibers in the papillary dermis of patients.

Alternatives to Estrogen for Skincare

Phytoestrogens are another option. They tend to appear in anti-aging creams as plant derivatives such as black cohosh or isoflavonoids derived from soy. It turns out that black cohosh may not even be a phytoestrogen. Soy isoflavones, on the other hand, are a class of estrogen-like compounds, specifically genistein and daidzein. There are a few studies that suggest that soy is promising.  In 2004, European researchers found that soy extract resulted in increased collagen and HA synthesis and “appears to rejuvenate the structure of mature skin”.

Estrogen and Acne

But some dermatologists are not convinced. Acne (of the post menopausal varieties) is one of the skin conditions that estrogen is supposed to help with. Decline of estrogen can leave testosterone unopposed and this can increase sebum activity leading to acne. However, Diane Thiboutot, M.D at Penn State Hershey College of Medicine the concentration of estrogen needed to decrease sebum production would need to be very high. If there were high doses of topical estrogens, they might be able to reduce sebum production and offset the effects of androgen and the development of acne, but there would be concerns about systemic side effects."

Concerns About Estrogen

How likely are those systemic effects? Dr Leslie Baumann cites a trial by Kainz et al on 17 women for three months with a topical that suggested no systemic effects and estrogen may, therefore, she concludes be useful for aging skin. Nonetheless, she urges extreme caution and treatment of a small area only by post-menopausal women.

Another part of the concern about estrogens in cosmetics is that they are there "by stealth" as ingredients that mimic human estrogen (albeit usually weakly), such as parabens and they have been controversially been linked to cancer. Some of these ingredients and the types of concerns are in my post Estrogen In My Shampoo and Copley’s Estrogen In My Face Cream.

The way I feel about topical estrogen is that there may be risk of cancer. Certainly more research is needed on this area. In the meantime, the evidence of benefits of topical estrogen hasn’t convinced me to take that risk with a hormone gel. Would that mean I would ditch a cream that had soy or black cohosh in it? No, not yet. When I looked at soy in some detail, it seemed to me that there wasn't a very robust link to cancer in studies done so far and the amounts in cosmetic formulations are relatively small. On the other hand, they don't really convince me as skin rejuvenators so I won't be going out of my way to use them either.