observations. Wright may have been the first proponent of BHT to use the term bioidentical—the word he coined to describe unpatentable, plant-derived molecules he believed were identical to human hormones. However, no structural crystallographic evidence has been used to support the idea that these molecules are identical to endogenous human hormones. When the Women's Health Initiative's reports on the unappreciated risks of equine estrogens were released, many prescribers of BHT used Wright's assertions (and his terminology) to proclaim the superiority of bioidentical molecules despite a lack of scientifically supported evidence. Following the publication of a popular book written by Suzanne Somers in 2006, the term bioidentical gained more prominence in popular consciousness as a "poorly understood new adjective" regarding hormone replacement therapy. Terminology There is no single definition for the term bioidentical hormone replacement therapy; 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 not all allegedly bioidentical hormones sold by custom-compounding pharmacies are necessarily molecularly identical to endogenous humans). The FDA considers BHT as currently used by BHT advocates to be a marketing term, not a scientific 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 non-bioidentical hormones can be produced from the same plant sources. BHT is often used to refer to a set of diagnostic, prescribing, preparation and marketing practices including compounding, saliva testing, and an emphasis on countering the effects of aging rather than relieving the symptoms of menopause. This compounded BHT package has been promoted by Somers, Oprah Winfrey, and other proponents as safer and more effective than CHRT, though there is no evidence to support these claims. Compounded BHT has been marketed on the internet by pharmacies that make unfounded claims for its safety and its effectiveness for a variety of conditions. There are a variety of FDA-approved products, made using bioidentical estrogens and micronized progesterone, used to treat the