A little goes a long, long way.

By John R. Lee, M.D.

I get many questions about what dose of estrogen to use. My favorite answer is, “the lowest dose possible that will relieve symptoms,” but I understand that you need more specific information.

Keep in mind that the information I’m giving you here is a starting point. From here you want to track your symptoms and saliva hormone levels, until you find the optimal dose. Be aware that your optimal dose could change. As you age, if you gain or lose weight, substantially change your diet or start taking other hormones or medications, your need for estrogen can increase or decrease.

There are three major estrogens made by humans: estrone, estradiol and estriol. Estriol has great benefit to the cells of the vagina, but has little effect on breasts or bone. The good news about that is that it doesn’t seem to promote breast cancer, and may even be protective against it. The bad news is that it doesn’t help retain bone. However, if a woman has vaginal dryness and/or vaginal cell atrophy, estriol is the best estrogen to use. The recommended dose is just 0.5 mg twice weekly in a cream, applied vaginally.

The most widely used and recommended estrogen for menopausal symptoms in general is coming to be estradiol. Premarin used to be the first choice, but both doctors and patients have begun to realize that Premarin isn’t estrogen per se, it’s a cocktail of hundreds of substances found in an extract of pregnant horse urine that includes both the estrogen estrone, found in humans and horses, and equilin, an estrogen found only in horses. In contrast, when you take estradiol, you know exactly what you’re getting: a bioidentical hormone, meaning one that exactly matches what your body makes.

How Much to Take
In the U.S., the lowest available dose of oral (pill) estradiol (as Estrace, for example) is 0.5 mg. But that tablet is scored so it will easily break into two halves, each containing 0.25 mg of estradiol. Thus, a bottle of a hundred tablets of 0.5 mg estradiol will last for 200 doses. At 25 doses a month, that bottle will last for 8 months.

Estradiol is also commonly used in patches, and this is undoubtedly the optimal way to deliver estrogen to the body. Estrogen patches used to be way too heavily dosed, but with the realization that they were 10 to 20 times more efficient than the oral doses, the amount released has been reduced. The patches available in the U.S. release 0.1 to 0.025 mg per 24 hours. Thus, for most women the optimal starting dose will be the 0.025 mg patch. Here, too, it is wise to have 4 to 5 days each month without an estrogen patch.

If for some reason your doctor wants you to use estrone, the recommended dose is 0.3 mg or less of oral estrone, or 0.03 mg or less of transdermal estrone.

Timing
In the case of all of these hormones, it is wise to take a little vacation from them for 4 to 5 days or so each calendar month. It helps to re-energize the hormone receptors and it helps to prove that your estrogen doses are not too high. If postmenopausal women take more estrogen than they need, they will have vaginal bleeding (assuming the presence of a uterus) and this will show during the days of not using the hormones. If that happens, you reduce the estrogen dose. There is no reason for postmenopausal women to recreate their periods.

If scattered vaginal spotting occurs, it is wise to consult with your doctor to rule out the risk of cancer of the uterus. Several recent studies show that progesterone is an important protector against cancer of the uterus, as well as against breast cancer. That is why no woman should ever take extra estrogen without also taking progesterone.

If you’ve been using PremPro and want to get off it, to avoid hot flashes it’s best to begin with the same dose of Premarin for a month, along with progesterone cream (this requires getting a separate prescription for Premarin). The second month, reduce the Premarin in half, either with a weaker dose pill or by breaking it in half. By the third month you should be able to switch to estradiol if you want to without experiencing a lot of hot flashes.

Here's where you can test your estrogen levels.