Hormone Replacement Therapy
As women enter menopause, their hormone levels will fluctuate considerably — estrogen production drops as the ovaries approach the end of their functional life, leading to weaker bones, vaginal infections and dryness, mood changes as well as hot flushing sensations. Physicians had traditionally prescribed regular hormone replacement therapy (HRT) until a study was released in the 2000s showing that the side-effects of HRT included clot risks and breast cancer. Physicians and patients then tried to find other sources of hormones, leading to new nomenclature: “Natural” vs “Bio-identical” Hormones.
What are Natural and Bio-Identical Hormones?
“Natural” hormones are those derived from animals, plants or minerals — for example soy or yam plants, or the urine of horses. They have not necessarily been tested for efficacy or potential harm, and thus the name is largely a marketing term.
“Bioidentical” hormones are those identical in structure to those found in women’s bodies. These molecular structures are not found in nature, but are modified from hormones found in Yam and Soy plants. Bioidentical estrogens include 17 beta-estradiol, estrone, and estriol. (Estradiol is the form of estrogen that decreases at menopause.) Bioidentical progesterone is simply progesterone. It’s micronized (finely ground) in the laboratory for better absorption in the body. Our bodies cannot differentiate bioidentical hormones from those that are ovary produced.
The conflict between “Natural” and “Bioidentical” hormones exists whereby some natural hormones are not bioidentical — for example, Premarin, which is naturally sourced pregnant horses, are not bioidentical because they are not found in humans. This could lead to inaccurate hormone test results when measuring one’s hormone levels, and this is one of the main tenets of support for bioidentical hormone use over natural hormones.
Where can I find Bioidentical Hormones?
Bioidentical estrogens and micronized progesterone are made into a range of products, many of which are FDA-approved and available with a prescription at your local pharmacy. Commercially available bioidentical estradiol comes in many forms and include: Estrace, Esclim, Estraderm, Vivelle, Estrogel, Estring, and Vagifem. Orally ingested estradiol is converted in the liver to estrone, a weaker estrogen, but given topically via creams, gels, or patches is more wholly absorbed. Women who still have a uterus and are taking Estrogen replacement therapy should still take a Progestin or micronized Progesterone to decrease the chance of endometrial cancer.
Commercially available bioidentical progesterone is currently available as Prometrium.