Bioidentical hormone replacement therapy (BHRT), also known as bioidentical hormone therapy or natural hormone therapy is a generally ill-defined term that frequently refers to the use of hormones that are molecularly identical to endogenous hormones in hormone replacement therapy, but is also strongly associated with pharmacy compounding, blood or saliva testing, efforts to reach a targeted level of hormones in the body (as established through blood or saliva testing) and exaggerated, unfounded claims of safety and efficacy. Specific hormones used in BHRT include estrone, estradiol and progesterone, which are available both in FDA-approved manufactured products and as pharmacy-compounded products as well as testosterone, dehydroepiandrosterone (DHEA) and estriol which have not been approved for use in Canada and the United States. The use of compounded BHRT is a practice that primarily appears in the United States. Proponents have promoted BHRT as a panacea for nearly all disease rather than a means of relieving the symptoms of menopause and/or reducing the risk of osteoporosis (the goals of traditional hormone replacement therapy), but there is no evidence to support these claims and the hormones are expected to have the same risk and benefits of comparable approved drugs for which there is an evidence base as well as extensive research and regulation (the exception is progesterone which may have an improved safety profile, though direct comparisons with progestins have not been made). Bioidentical hormones may also present extra risks due to the process of compounding. In addition, the accuracy and efficacy of saliva testing has not been definitively proven, and the long-term effects of using blood testing to reach target levels of hormones has not been researched.

A major safety concern of bioidentical hormone replacement therapy is that there is no requirement to include package inserts despite the potential for serious adverse effects, including life threatening adverse effects, being associated with HRT. This can lead to consumers being deceived and even harmed as they are mislead into believing that BHRT is safe and has no side effects. Regulatory bodies require pharmacies to include important safety information with conventional hormone replacement therapy (CHRT) via package inserts