Terminology
There is no single definition for the term "bioidentical hormone replacement therapy" (BHRT); it is generally used to refer to 17β-estradiol, but other uses include plant-based or compounded estrogen products that blend estradiol with estriol and sometimes with estrone. A "bioidentical hormone" is defined as a molecule identical to a hormone produced by the human body. Though the term "bioidentical" has been used in FDA packaging inserts since before 1998, the FDA considers "BHRT" to be a marketing term and does not recognize its use. The meaning of "plant-derived" has also been attached to the term "bioidentical", and it may also mean that the hormones are "natural"; throughout the 1990s plant-derived, compounded hormones were referred to as "natural hormone therapy". However, the term "natural" can be applied to all products where the principal ingredient originates from an animal, plant, or mineral source, and both bioidentical and nonbioidentical hormones can be produced from the same plant sources.
"BHRT" is often used to refer to a set of diagnostic, prescribing, preparation and marketing practices including compounding (the preparation of custom-mixed hormones by a pharmacist, according to a prescription), saliva testing, and efforts to counter the effects of aging rather than relieving the symptoms of menopause. This compounded BHRT package has been promoted by Suzanne Sommers, Oprah Winfrey and other proponents as safer and more effective than CHRT, though there is no evidence to support these claims. Compounded BHRT has been marketed on the internet by pharmacies which make unfounded claims for its safety and its effectiveness for a variety of conditions.
The lack of distinction between FDA-approved bioidentical hormones and compounded bioidentical hormones as part of a package that includes saliva testing and compounding has resulted in considerable confusion regarding exactly what BHRT is.
There are a variety of FDA-approved products made using bioidentical estrogens and micronized progesterone, used to treat the symptoms of menopause:
| Hormone class | Type | Brand names | Preparations | Notes |
|---|---|---|---|---|
| Estrogens | ||||
| Micronized estradiol | ||||
| Estrace and others | Pill and vaginal cream | Vaginal cream for vaginal symptoms only; sourced from plants; estradiol is bioidentical until ingested and converted in the liver to estrone | ||
| Alora, Climara, Esclim, Estraderm, Vivelle and others | Patch | Sourced from plants | ||
| Estrogel | Transdermal gel | Sourced from plants | ||
| Estrasorb | Topical cream | Sourced from plants | ||
| Estring | Vaginal ring | For vaginal symptoms only; sourced from plants | ||
| Estradiol acetate | Femring | Vaginal ring | ||
| Estradiol hemihydrate | Vagifem | Vaginal tablet | For vaginal symptoms only | |
| Micronized progesterone | ||||
| Micronized progesterone | Prometrium | Pill | ||
| Prochieve 4% | Vaginal gel | |||
| Combined preparations | ||||
| Estradiol and norethindrone acetate | Combipatch | Patch | Estradiol is bioidentical, but the progestin is not | |
| Estradiol and norgestimate | Prefest | Pill | ||
| Estradiol and levonorgestrel | Climara Pro | Patch |
The term "synthetic" is also used incorrectly by lay "experts" in two different ways - to refer to the process used to manufacture all estrogens, including bioidentical estrogens, and to compounds that interact with estrogen receptors similar to estrogen molecules but are not found in nature. Examples of the latter two include diethylstilbestrol and ethinylestradiol.
Read more about this topic: Bioidentical Hormone Replacement Therapy