The Transdermal Estrogen Therapy Trend

By: Red Hot Mamas

Published: May 26, 2010

Written by Menopause Minute® Editors

We all have our creative ways to deal with hot flashes in the scorching summer months. Some of us keep an ice bucket nearby, others simply do not leave their always cool, air conditioned homes.  Most women experience hot flashes around menopause for 6 months to 2 years, making the hide at home with your fan option a little impractical. Ladies, it’s time to come out of hiding and face the hot flashes head-on!

When we become menopausal, our bodies produce less estrogen; it’s a fact. The plunge in estrogen levels cause those sadistic symptoms many of us are plagued with (including hot flashes,  night sweats, mood swings ,etc.).

Estrogen therapy (ET), is the most effective way to relieve hot flashes during menopause.  It also may reduce the risk of osteoporosis and other conditions that may develop at menopause.

Hot Flash Fast Facts

According to the Study of Women’s Health Across the Nation (SWAN):

  • The "menopause transition" means the time from the end of premenopause (when a woman’s periods are similar to what they have always been) to..

  • Perimenopause (when periods are changing in length, bleeding characteristics and/or frequency), to…

  • Postmenopause (12 months or more with no period, without an explanation like pregnancy or medication use).

  • 20% of premenopausal women experience hot flashes and night sweats

  • 57% of perimenopausal women experience hot flashes

  • 50% of postmenopausal women experience hot flashes (at least up to age 55)

What methods are available for taking ET?

Today, there are two main rules to keep in mind when taking any ET:

  • Lowest dose
  • Shortest amount of time

Next, there are several ways ET can be taken:

  • Through the mouth (oral)
  • Through the vagina (vaginal)
  • By injection
  • Through the skin (transdermal)

Two of the most common delivery methods are oral (taking pills or tablets) and transdermal (applying medication directly to the skin).

Oral estrogen therapy (ET) remains the most widely used formula in North America. However, evidence suggests oral delivery may lead to some undesirable side effects from being absorbed through the liver.

The transdermal route has a long history of use in Europe.  Approximately 70% of estrogen therapy use in France and Italy is taken as a transdermal treatment.  It’s recently starting to gain popularity in the United States, especially after the Women’s Health Initiative (WHI) raised so many unanswered questions about hormone therapy pills.

How does oral ET work?
Oral ET is swallowed.  The body then processes the estrogen through the gut and liver before it moves through the bloodstream.   It has been argued this can affect the functions of the liver and is presumed to be one of the reasons various routes of administration impact lipid profiles differently.  Also, when taken orally, the amount of estrogen (primarily estrone sulfate) available to circulate through the body can significantly decrease; therefore requiring more of the medication to be taken. This potentially works against the “lowest dose” rule (above).

How does transdermal ET work?

Transdermal ET is absorbed directly through the skin into the bloodstream without passing through the liver.  When compared with oral ET, transdermal ET has shown to have a lower risk of causing blood clots, cardiovascular complications and other conditions. Transdermal estrogen therapy is available in several forms including:

  • Patch
  • Gel
  • Lotion
  • Spray
  • Vaginal cream
  • Vaginal ring

Transdermal delivery systems can provide more consistent levels of estrogen than the oral delivery system, which can fluctuate. This option may be appealing for women who are concerned about the risks and side effects of taking oral estrogen. 

What do the studies show about orals and transdermals?
Lots and lots of studies are being conducted on the many types of menopausal hormone therapy. The sheer amount of information can be overwhelming and at times can even appear contradictory. Sorting through the information is important in the decision making process when choosing to use HT (as any other treatment should be). So, what do the large studies say? Here are some of the important ones:

Women’s Health Initiative (WHI): The WHI was halted in 2002 when the concern for blood clots greatly increased. WHI found at least 44 percent of the adverse effects of HT were related to blood clots. Many professionals criticized WHI because researchers limited themselves by using only one type of estrogen (conjugated equine estrogen) and because it was administered orally (leaving out other types of estrogens and transdermal delivery.  An alternative type of estrogen is used in hormone patches, gels and creams (17-beta estradiol).  Results left us wondering if it would have been different, had researchers changed the type of estrogen and /or delivery method.

The Estrogen and Thromboembolism Risk Study (ESTHER): Conducted by French researchers, included 881 women who took either estrogen only or an estrogen-progestin combination. Results
suggested the type of HT and route of delivery make a difference. Women who took hormones in pill form were four times as likely to suffer a serious blood clot.

Kronos Early Estrogen Prevention Study (KEEPS): This is a currently ongoing trial, where recently menopausal women are receiving low dose oral or transdermal HT to see if they prevent or delay the onset of the number one killer of women, heart disease. KEEPS is enrolling participants aged 42 to 58 years, with their last menstrual cycle having occurred within 6 months to 3 years.

Bottom Line
Estrogen is the only pharmacologic therapy government approved in the United States and Canada for treating menopause related symptoms.  Some estrogen products are also approved for the treatment of vaginal dryness and symptoms of vulvar and vaginal atrophy.  As with any estrogen preparation, it should be used with a progestogen in women with a uterus.
Transdermal estrogen therapy may be an appealing route for women who are concerned with the risks and side effects associated with taking an oral preparation or for those who are looking for an alternative delivery method.
The decision to use hormone therapy at menopause is a very personal, individualized one where all risks and benefits should be weighed with a healthcare professional.  Hormone therapy is not right for everyone but only you and your doctor can make that decision.  Always use the lowest dose for the shortest amount of time necessary to relieve symptoms.

Learn More
To learn more about transdermal estrogen therapy, bioidentical hormone therapy and the importance of FDA approval when choosing any form of HT, join our lively discussion on August 4, 2009 at 9PM EST. The Buzz on Bioidenticals Webinar will clarify your questions on menopausal hormone therapy. Register TODAY!

Read the special patient education magazine, The Buzz on Bioidenticals for more information. Published by The Female Patient, a leading medical journal for obstetrician-gynecologists with contributions from the Red Hot Mamas and Dr. Elizabeth Lee Vliet, women’s health physician/hormone therapy expert: Available NOW!


Shulman, Lee. "Advances in Treating Vasomotor Symptoms in Postmenopausal Women." The Female Patient 06 2008 4. Web.8 Jul 2009. <>.

Simon, James. "Transdermal Estrogen Therapy: Evidence and Update." The Female Patient 11 2007 8. Web.8 Jul 2009. <>.

“What You Should Know About Transdermal Hormone Therapy.” The Female Patient Patient Handout, 04 2009 1. <>.