Hormone Replacement Therapy has two subcategories: Combination HRT and estrogen-only HRT.
- Combination HRT includes both estrogen and progestogen, taken either separately or in one formulation. The estrogen is intended to replace the estrogen the body is losing naturally due to menopause. Progestogen is there to lower the risk of cancer in the uterus, since estrogen given by itself can increase that risk. Progestogen can take the form of progestin, which is a synthetic form of the hormone, or progesterone, which is derived from natural sources.
- Estrogen-only HRT contains estrogen only, which is appropriate for women who have had their uterus removed.
HRT is systemic therapy, which means that it sends hormones into the bloodstream so they can travel throughout the entire body. The therapy can take the form of a pill; an injection; or a patch, gel, cream, or spray that delivers the hormones through the skin.
HRT is different from local estrogen therapy, which is applied to or delivered inside the vagina for direct relief of symptoms such as dryness, irritation, and pain. Local estrogen therapy can take the form of a cream, ring, or suppository—and although some estrogen does make it into the bloodstream, the amount tends to be small. Unlike HRT, it is designed to treat the vaginal area, not to raise hormone levels throughout the body. To learn more about local estrogen therapy, visit our section on Menopausal Symptoms: Vaginal Changes.
You’ll see other terms frequently associated with HRT. You may hear people talk about “bioidentical hormones,” which basically means that the hormones have the same chemical structure as those produced by the body. Bioidentical hormones are derived from plant sources. Non-bioidentical hormones do not have the same structure as those made by the body, and they can come from animal or plant sources.
There have been claims that bioidentical hormones are a safer, “natural” alternative to traditional hormone therapies. Even though these hormones are derived from plants—hence the label “natural”—they still have to be processed in the lab. Many of the commercially available therapies that are manufactured by pharmaceutical companies do contain bioidentical hormones. There also have been claims that hormone therapies produced by compounding pharmacies are somehow “more natural” than commercially available preparations. Compounding pharmacies take the necessary active ingredients and formulate the therapy for an individual patient. However, the compounding pharmacies often use many of the same ingredients that pharmaceutical manufacturers do. Any claims that a certain form of HRT is more natural or safer are not yet proven by data. In fact, the American Congress of Obstetricians and Gynecologists has stated that data do not support the use of compounded bioidentical hormones for menopausal symptoms.
All forms of HRT that are available commercially have been reviewed and approved by the U.S. Food and Drug Administration (FDA). Historically, the FDA has not overseen HRT produced by compounding pharmacies. As of late 2013, however, the nation’s largest compounding pharmacies are subject to review by the FDA, but smaller pharmacies are not, so safety and effectiveness are still a concern.
All of the terms can get confusing, but here’s the take-home: There is no clear evidence that certain types of HRT are safer or more natural than others.