The ABCs of HRT

Hormones are a Godsend for some women and just aren’t appropriate for others.

By Christiane Northrup, M.D.

The topic of hormone replacement therapy (HRT), especially with bioidentical hormones, seems to raise more questions than answers. Given the amount of misinformation and confusion that exists, I have prepared the following primer. It covers the ABCs of HRT and addresses some of the most commonly asked questions.

Who Needs Hormone Support?

Healthy women who go through perimenopause—the five to twelve year process leading up to the final menstrual period—may not require any additional hormone support. Menopause is, after all, a natural process, not a medical event requiring medication. In fact, some women make all the hormones they need from their own adrenals and ovaries, and they sail through the process. Others enter midlife exhausted from chronic sleep deprivation, nutritional deficiencies, difficult marriages, or a lifestyle of over-giving to parents or children. Hence, these women are running on empty and their bodies lack the raw materials to produce adequate hormones. Women who’ve had hysterectomies with or without ovary removal frequently require additional hormone support because surgery interferes with the blood flow to the ovaries. The end result is low hormone levels. And, in the case of ovary removal, instant menopause.
Note: Menopause refers to the final menstrual period. When we use the term “menopausal” we really mean that someone is going through the process of perimenopause. This process ends a year or so after the final menstrual period. The final menstrual period is a retrospective diagnosis. You don’t know you’re done until one year has passed. During that year you could still get pregnant, so use birth control! You may require hormonal support both during and after perimenopause.

What Hormones Do You Need?

Although there are a lot of jokes and stereotypes about midlife women needing estrogen, there are actually three hormones that can drop to low levels or become out of balance relative to one another. These hormones, sometimes referred to as the sex hormones, are estrogen, progesterone, and androgens such as testosterone. Because all three hormones are produced by the ovaries, when a woman approaches menopause and stops ovulating, these hormone levels typically change.

While some women might be perfectly comfortable with no supplemental hormones, some might need progesterone only and some might need all three. Another thing to keep in mind is, as you transition from perimenopause to post menopause, you might need to adjust which hormones you are taking. This can mean adding or subtracting a specific hormone, increasing or decreasing an amount, and even eliminating them altogether.

  • During perimenopause, women begin to skip ovulations causing a decline in their primary source of progesterone. This results in irritability, sleeplessness, anxiety, and premenstrual migraines. Natural progesterone can calm these symptoms very effectively. Sometimes the only thing that is necessary is 1/4 tsp. –1/2 tsp. of 2% progesterone cream (about 30-60 mg), which is available over the counter. Research has shown that small amounts of transdermal progesterone are, indeed, absorbed into the blood stream.1
  • Another common complaint of perimenopause is hot flashes. Hot flashes and night sweats are caused by fluctuating levels of estrogen, which is why estrogen therapy is the gold standard for relieving hot flashes. I always recommend using the lowest dose you need to feel better. Interestingly, natural progesterone cream can also relieve hot flashes in many women.
  • Some women also experience midlife chest pain from coronary artery spasm. Natural progesterone has been shown to be very helpful in this regard—and at very low doses of only 30 mg (1/4 tsp. of 2% progesterone cream) applied as a cream to the skin.2
  • Many women experience a waning sex drive during perimenopause. Most of the time, this is the result of unfinished business in a relationship, the need for more sleep, low vitamin D levels, or simply the need to reinvent oneself. (That’s why the number one predictor of good midlife libido is a new partner! I always tell people that they need to become that new partner, not necessarily ditch their husbands.) Often, a low sex drive is associated with low testosterone levels, so a little bit of testosterone (or its precursor, DHEA) supplementation may help.
  • Vaginal dryness can play a part in loss of sex drive, too. For most women, a little estrogen applied vaginally is all that’s needed to restore sex drive and make intercourse more pleasurable. Some don’t even need that. A little KY Jelly or one of the other numerous lubricants on the market is fine.

For more information about perimenopausal symptoms and the common effects of lower hormone levels on your body and overall health, refer to The Wisdom of Menopause.
What About Thyroid Hormones?

When women start skipping ovulations, they may develop a condition known as “estrogen dominance”—too much estrogen relative to progesterone. In the face of excess stress hormones, this estrogen itself can be metabolized into substances that act like stress hormones. To compensate, the body will often lower levels of thyroid hormone so as not to overstimulate the heart beat, and so forth. The result is subclinical hypothyroidism. So it’s always a good idea to get your thyroid checked. Your TSH level should be no higher than 3, even though in many labs the range for normal is up to 4.5!

Up to 15 percent of women are iodine deficient, which can also cause subclinical hypothyroidism—as well as sore breasts! (Believe it or not, breasts require 3 mg of iodine per day to be healthy!) The safest way to increase your iodine level is through eating kelp tablets, seafood, and a couple eggs per week. Iodine supplements are available, of course, but it’s important to work with a healthcare practitioner who has experience with this.

What Are Bioidentical Hormones?

Simple. They’re hormones that match, exactly, the hormones found in your body. Their chemical structure and shape were designed by Mother Nature, not by a pharmaceutical company. The raw materials used to make bioidentical hormones are yams and soybeans. Pharmaceutical companies then create various hormones from these plant precursors. Some are bioidentical; some are not.

Bioidentical hormones cannot be patented because they occur naturally. Hence drug companies have had to make synthetic hormones with hormone-like effects in order to make a profit from hormones. This is also why the vast majority of hormone research has been done with synthetic hormones, including estrogens derived from horse urine.

However, it is possible to patent the delivery systems of bioidentical hormones, which is why we now have a wide variety of patches and vaginal gels that use bioidentical hormones! The availability of these preparations is largely the result of market pressure from those of us who want safer and more natural solutions. Not only are these available by prescription, they can be purchased in a typical pharmacy, including those that accept insurance.
Note: Don’t be fooled. The label “natural” or “plant based” is virtually meaningless. The only thing that’s important when it comes to a hormone is that it match exactly what’s normally occurring in the human body!

Are Progestins and Progesterone the Same?

Progestins are a class of hormones that include bioidentical progesterone. There is only one progesterone, but there are many synthetic progestins that have some progesterone-like actions in the body. Medroxyprogesterone acetate (MPA), brand name Provera (and also used in Prempro), is a good example. It’s often confused with natural progesterone because it’s referred to as a progestin. Similar sound, different substance entirely.

Because MPA isn’t found anywhere in nature, it has far more side effects that natural progesterone. It can cause PMS symptoms, headache, bloating, and even constriction of coronary arteries. Numerous studies show that natural progesterone typically relieves these cycle-related concerns and confers relief for women with angina.

But because MPA and other progestins are lumped in the category “progesterone” in the medical literature, many doctors think it’s the same thing as bioidentical progesterone. In addition to causing more side effects than natural progesterone, synthetic progestins aren’t metabolized by the body in the same way.

There are several “progestins” that have progesterone-like activity. In addition to MPA, norethindrone acetate and norgestryl are frequently used in synthetic HRT formulations. These three progestins are commonly found in birth control pills, too. The only “real” progesterone occurs naturally in the female body (or is made in the lab to match it exactly).

Are Hormones Safe?

Bioidentical hormones are, theoretically, safer than estrogens made from horse urine or synthetic progestin. As a matter of fact, some studies show that natural progesterone is far safer than synthetic progestin. The large KRONOS study that is due out this year will answer a lot of our questions about this issue. The bottom line is that because of the confusion about which hormone preparations are bioidentical and which are not, most experts lump everything together and warn women of the well-defined risks that have been associated mostly with the synthetic compounds. That said, even bioidentical estrogen is a growth hormone in the body and may have adverse effects on uterine and breast tissue, especially if not balanced with progesterone.

The truth is that hormones are a Godsend for some women and just aren’t appropriate for others—one-size-fits-all is obsolete medicine. There’s no harm in trying a small amount of bioidentical hormone replacement to see if it’s right for you. You will know very quickly because your body will either say yes or no.

Are Pills or Creams Better?

The most physiologic way to take hormones is through the skin—either with a cream or a vaginal gel. That way the hormone goes right into the blood stream without having to be metabolized by the liver. All the patches work this way (transdermally). There are a number of estrogen gels available and a progesterone gel that is used vaginally. Because taking hormones in pill form forces the liver to first process the hormone, you have to use bigger doses to get the same effect. This is undesirable because it can cause the liver to produce increased clotting factors.

How Do Stress Hormones Affect Perimenopause?

The stress hormones cortisol and epinephrine, which are produced by the adrenal glands, can wreak havoc on normal hormone metabolism. For example, if you are skipping ovulations, have progesterone levels that are very low, but estrogen levels that are high (called estrogen dominance), your body will convert your estrogen into substances that act like additional stress hormones. That’s why so many women notice that their symptoms go away when they learn to meditate, get more sleep, or go on vacation. Their bodies, when relaxed, can metabolize excess stress hormones beautifully.

Hormone metabolism also gets messed up by following a diet that’s high in foods that elevate blood sugar such as white bread, white potatoes, and white sugar products.

Many experts believe that the key to quelling menopausal symptoms lies in getting stress hormone levels under control. Given that stress hormones are associated with everything from midlife weight gain to poor sleep, I certainly agree!

What Is a Compounding Pharmacy?

Compounding pharmacies, also called formulary pharmacies, specialize in creating hormone (and other) prescriptions tailored to individual needs. The bioidentical hormones used by compounding pharmacies are all FDA approved—and are the same hormones that drug companies also use in their pills, patches and vaginal gels.

How Do You Individualize Your Treatment?

A full range of bioidentical hormones—either singly or in combination—is available by prescription from formulary pharmacies. The dosages can be individually adjusted. Hormones can be prescribed based on a woman’s test results and symptoms so she is taking only what she needs to maintain the optimal levels of hormones in her body. (This approach is standard with thyroid hormone, but wasn’t applied to sex hormones until recently.) It’s also possible to create a bioidentical hormone replacement regimen using hormone preparations available in all conventional pharmacies. You just have to know which brands are bioidentical and which are not. Refer to The Wisdom of Menopause (Bantam, 2006), Chapter 5 for a list or ask your doctor.

One popular form of hormone replacement therapy is to have a prescription created especially for you using a combination of one or more of the bioidentical estrogens (estradiol, estrone, estriol) combined with bioidentical progesterone and an androgen in the form of DHEA or testosterone, if needed. These hormones are mixed into a lotion, cream, or other base and applied to the skin. Because the estrogen known as estradiol can be converted by the body into the other types of estrogen, I generally recommend just that one.

Is Hormone Testing Helpful?

Hormone testing is controversial because a hormone level measures only a point in time (like looking at the speedometer in our car only once during a road trip) and hormones fluctuate widely throughout the day. (This applies to blood, saliva or urine tests.) Results also depend upon what you eat, your activity level, the time of day, and your nutritional status. Still, a baseline blood test is a good starting point for monitoring therapy. At this point in time, the vast majority of experts agree that blood hormone values are the most reliable compared to saliva. These should be done by a lab that has a lot of experience in this area such as Genova Diagnostics. Their Hormonal Health profile is very comprehensive. Another good lab is My Med Lab, which doesn’t require a healthcare practitioner’s order.

How Can You Find a Healthcare Practitioner?

Fortunately, more and more healthcare providers are knowledgeable about bioidentical hormones. To find one, I recommend going to the Web site of the American Holistic Medical Association or the Institute for Functional Medicine. Nurse practitioners who specialize in women’s health are also very good at it, and so are many ob/gyns. Another way to find a practitioner is to contact the International Academy of Compounding Pharmacists to find a compounding pharmacy near you. They will usually be happy to provide you with the names of local practitioners who work with them.

Where Can You Go For More Information?

Remember that a one-size-fits-all approach to hormone replacement therapy (HRT) is not good medicine—every woman is different. If you’re approaching or in perimenopause, I encourage you to learn all you can about the different options so you can partner with your doctor effectively. Midlife and beyond can be the best years of your life! They don’t have to be laden with medical challenges.

My book The Wisdom of Menopause is a complete resource for health concerns at midlife, and Chapter 5 provides in-depth information in hormone therapy—it even lists the names of some of the bioidentical formulations available with a prescription at conventional pharmacies, such as Estragel (bioidentical 17 beta estradiol as a skin cream).

Learn More | Recommended Reading


  1. 1.Burry, K., Patton, P., Hermsmeyer, K., 1999. Percutaneous absorption of progesterone in postmenopausal women treated with transdermal estrogen. American Journal of Obstetrics and Gynecology, June 180(6 Pt1):1504-11.
  2. 2.Hermsmeyer, K., et. al, 2008. Cardiovascular effects of medroxyprogesterone acetate and progesterone: a case of mistaken identity? Nature Clinical Practice: Cardiovascular Medicine, Jul 5(7):387-95.

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  • Lesa613

    I was told by my Md that HRT was the way to go for hot flashes. is afraid Getting breast cancer so I have been researching alternative therapy.
    So I found a product called OONA with black cohosh and chaste berry. It seems to be doing the trick thus far and it has only been 24 hrs. I was suffering with the heat for the past two plus weeks and felt I was going crazy, up all night and miserable.
    I am so glad that I found this product and hope it continues to work.