"Bioientical" hormone replacement therapy (BHRT) is the use of supplemental doses of steroid hormones with a chemical structure identical to endogenous human hormones (hormones naturally produced in the human body). On 1/10/2008 the US Food and Drug Administration sent letters warning seven pharmacy operations that the claims they make about the safety and effectiveness of their so-called "bio-identical hormone replacement therapy," or "BHRT" products are unsupported by medical evidence, and are considered false and misleading by the agency. The FDA is concerned that unfounded claims like these mislead women and health care professionals. Generally BHRT is prescribed to relieve the symptoms of menopause, though more recent therapies promise anti-aging effects and possible deferral of the diseases of aging. BHRT differs from conventional hormone replacement therapy, which by definition uses animal or synthetic hormones whose structures are similar or identical to those produced in the human body.