When the oestrogen/progestin (synthetic progesterone) arm of the Women’s Health Initiative (WHI) study abruptly shut down back in July 2002, women were shocked . . . stunned. It wasn’t only the study’s participants. It was equally devastating to the millions of other women around the world taking hormone replacement therapy (HRT), thinking they were doing something good for themselves.
The sudden knowledge that they might be risking coronary heart disease, breast cancer, stroke or pulmonary embolism so terrified women that many immediately quit their hormones, cold turkey.
Then in February 2004 came the aftershock: the oestrogen-alone (oestrogen replacement therapy, or ERT) arm of the study shut down when it became apparent that it not only failed to prevent heart disease ― it increased the risk of stroke.
Besides shock, fear and disappointment, the WHI failure sparked enormous confusion over the use of hormones to ease the transition into and through menopause.
Today, we understand a great deal more about hormones, and we have the option of bioidentical hormones (BHRT), but we still have confusion, especially about what kind of oestrogens to take. Sublingual drops? Patches? Pills? Injections? Pellets? Vaginal ring? Transdermal gels and creams (which are preferable and safer)?
It’s enough to make you dizzy! But to try and clear up some of the confusion, and to make things a bit simpler, I’m going to focus on only one question: Of the two most popular oestrogen-delivery systems, which is best ― oral (pills) or transdermal (applied to the skin)?
Oral oestrogens are used in ERT and HRT, and transdermal oestrogens are used in bioidentical hormone restorative therapy (BHRT), along with other natural hormones, such as progesterone.
But first, let’s clear up what makes ERT/HRT oestrogens different from BHRT oestrogens.
ERT/HRT vs. BHRT Oestrogens: What’s the Difference?
The most common form of ERT is Premarin®, a conjugated oestrogen obtained from the urine of pregnant mares. HRT, most often marketed as Prempro®, is a combination of, once again, horse oestrogens, and progestin, a synthetic substitute for progesterone.
Both come in a fixed-dose pill form. And they’re synthetic. That means these oestrogens are not of natural origin. They don’t replicate your own oestrogens ― they’re chemicals that merely imitate the natural hormone. They can’t function in your body the same way as the oestrogens created by your body.
To work properly, hormones have to bind with specific target receptor cells in your body, like a key in a lock. The synthetic form of hormones can’t completely bond with receptors because the key does not totally fit. Because of this, they can’t work as they should, they confuse the body, and therefore, can predispose you to cancer and other diseases.
On the other hand, BHRT oestrogens, like all bioidentical hormones, are derived from wild yam and soy plants. They have exactly the same molecular architecture as the oestrogens produced in your own body. That means they are fully equipped to do everything that your own ‘homemade’ oestrogens do ― including binding to receptors.
And as we will see, ERT/HRT and BHRT oestrogens are metabolized in completely different ways, which makes a world of difference in their safety and effectiveness.
What’s the Scoop on Oral Estrogens?
Unfortunately, what we’ve learned about oestrogens post-WHI has not attracted publicity anywhere near that surrounding the study’s sensational, premature end. As a result, many women are unaware of these advances. Nonetheless, we’ve gained a great deal of useful knowledge since then.
For one, we’ve learned about what happens when you swallow oestrogens in pill form ― specifically about what occurs in your body physiologically and how it affects the metabolism of the oestrogens you ingest.
Once you swallow an ERT/HRT pill, it makes a beeline for your liver. It passes through the gut, where it undergoes preprocessing. From there, it goes into the large portal vein and then on into the liver. There, it’s metabolised before it circulates throughout your system.
This route means that oral oestrogens enter the liver much more directly and in a much more concentrated form than the natural oestrogens created in your ovaries. With oral oestrogens, your liver is hit with a dose of around 1,000–2,000 micrograms of oestrogen instead of 100–200 micrograms.
It’s no exaggeration to say this is an overload that can stress the liver.
The effects of oral oestrogens can be erratic and unpredictable, varying with the dose and the individual. Oral oestrogens may:
- Increase or decrease the synthesis of various proteins in the liver, either raising or lowering levels of blood-clotting factors, testosterone, oestrogens and thyroid hormones, potentially resulting in blood clots, strokes, blocked hormone function, elevated blood pressure and triglyceride levels, and suppressed thyroid function
- Produce unwanted products of metabolism (metabolites) that increase risk of oestrogen-sensitive cancers
Initially, oestrogen-only fixed doses were set at high levels in order to relieve vasomotor menopausal symptoms such as hot flushes and night sweats. However, these doses have been shown to be excessive, causing adverse effects such as weight gain, water retention, fibrocystic breasts and the much more serious risks of breast and uterine cancers.
Later, when progestin (synthetic progesterone) was added to the horse oestrogens (as in Prempro), the uterine cancer risk lessened, but breast cancer risk increased, along with risk of blood clots, stroke and gallbladder disease.
What Makes BHRT Transdermal Estrogens Different?
Bioidentical transdermal oestrogen therapy comes in the form of a compounded (individually mixed) gel or cream that is applied topically. The dose is tailored to your test results, which show what is needed to restore your oestrogens to their optimal and proper levels.
Instead of being first metabolised by the liver, transdermal oestrogen acts exactly as the oestrogens produced by your ovaries. That is, it is transported through the bloodstream, reaches its target tissues, attaches to oestrogen receptors and is then metabolised in the liver. The liver is the end point, not the starting point. We are following nature here.
That completely alters how transdermal oestrogens works. Compared with oral oestrogens, BHRT transdermal oestrogens don’t:
- negatively impact liver protein synthesis
- produce unwanted metabolites that raise cancer risk
- increase your risk for blood clots, heart disease, stroke, gallbladder disease, etc.
- have unpredictable effects or
- stress your liver
It is also worth noting that oestradiol produced in your ovaries is easily eliminated in urine within one day, whereas synthetic oestrogens can remain in your body for up to 13 weeks before elimination. Your body is designed to metabolise your own oestrogens and, in this case, bioidentical hormones which are an exact copy of your own, NOT horse hormones.
And the Winner Is…
In the United Kingdom and the United States, HRT oral formulations of oestrogens are more frequently prescribed than BHRT transdermal formulations. Why this is so is unclear, but it’s high time to clear up the confusion.
Hands down, transdermal oestrogens are far safer and more effective!
True, ERT and oestrogens found in HRT have been studied much more extensively than BHRT oestrogens but much of that research leads to the conclusion that these synthetic hormones are not something you want to put in your body.
The clinical evidence on BHRT oestrogens is persuasive and mounting: Transdermal oestrogens have a far stronger safety and efficiency profile than oral ERT/HRT oestrogens. It’s not even close.
In the end, it comes down to one thing. To avoid risk of chronic disease and other health problems, the molecular structure has to be the same as that of your natural oestrogens. The same holds true for progesterone, which should always be taken with oestrogen to ensure maintenance of the correct ratio.
To make sure you’re prescribed BHRT transdermal oestrogens (together with progesterone), make sure to work with a doctor specially trained in restorative medicine and bioidentical hormones who understands why this form of oestrogen is preferable.
Estrogen Pill vs. Estrogen Patch ― Which Works Best? Virginia Hopkins Test Kits.
Gillson, G.R. and Zava, D.T. A Perspective on HRT for Women: Picking Up the Pieces After the Women’s Health Initiative Trial ― Part 1. International Journal of Pharmacological Compounding. Vol.7 No. 4, July/August 2003.
Liu, B. Is transdermal menopausal hormone therapy a safer option than oral therapy? Canadian Medical Association Journal (CMAJ). 2013 Apr. 16; 185(7): 549–550.
Which Type of Estrogen Hormone Therapy Is Right for You?