Bioidentical hormone replacement therapy (BHRT), also known as bioidentical hormone therapy or natural hormone therapy, is a poorly defined term referring to the use of hormones that are identical, on a molecular level, with endogenous hormones in hormone replacement therapy. The term is also 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 unfounded claims of safety and efficacy. Specific hormones used in BHRT include estrone, estradiol, progesterone (which are available both in FDA-approved manufactured products and as pharmacy-compounded products), testosterone, dehydroepiandrosterone (both products have more limited availability and approval in Canada and the United States) and estriol (which is available in Europe but is not approved in Canada and the United States). Custom-compounded BHRT is a practice almost wholly restricted to the United States. BHRT is a form of alternative medicine, and has been promoted as a panacea for many diseases rather than a means of relieving the symptoms of menopause and/or reducing the risk of osteoporosis (the goals of traditional hormone replacement therapy). There is no evidence to support these claims; the hormones are expected to have the same risks and benefits of comparable approved drugs for which there is an evidence base and 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 have not been researched. The International Menopause Society, American Congress of Obstetricians and Gynecologists, Society of Obstetricians and Gynaecologists of Canada, The Endocrine Society, the North American Menopause Society (NAMS), United States Food and Drug Administration, American Association of Clinical Endocrinologists, American Medical Association, American Cancer Society and the Mayo Clinic have released statements that there is a lack of evidence that the benefits and risks of bioidentical hormones are different from well-studied nonbioidentical counterparts; until such evidence is produced the risks should be treated as if they were similar; and that compounded hormone products may have additional risks related to compounding. A major safety concern in 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) associated with HRT. This can lead to consumers’ being deceived (and harmed), as they are misled 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.