Bioidentical hormones are made in the laboratory and are based on compounds found in plants (usually soy beans or wild yams). Unlike supplements containing soy or wild yam extract, a bioidentical hormone product has been processed by a specially trained compounding pharmacist.

After the plant-based hormone is processed, its structure is said to be identical to the estrogen, progesterone, or androgen hormone your body produces. (Well-designed studies have yet to prove this theory.²) A compounding pharmacist can offer you a custom-made formulation in one of many forms, such as a capsule, skin cream or gel, tablet to dissolve under your tongue, suppository, or nose spray. Some commonly prescribed estrogens and progesterones are bioidenticals, such as Estrace (estradiol).

Just like synthetic hormone replacement therapy, bioidentical hormone replacement is prescribed to increase or stabilize a woman's hormone levels. This is generally done during perimenopause, when hormone levels change unpredictably, and after menopause, when the hormones drop to low levels.

The most important fact to remember about taking bioidentical HRT is that its risks are not yet well understood. It may have the same breast cancer, stroke, blood clot, heart disease, and dementia risks that synthetic HRT has.¹