testosterone hormone therapy

Testosterone is a hormone that is naturally produced in the ovaries of women but also in various other tissues from pre-hormones produced in the adrenal gland. Most testosterone is bound to blood proteins such as sex hormone binding globulin (SHBG) and albumin, with only around 3-5% being free and available for your body to use. Conditions that elevate SHBG, such as using the oral contraceptive pill or oral oestrogen in MHT, can increase SHBG thereby reducing available testosterone. In PCOS and insulin resistance, SHBG is reduced (increasing the bioavailability of testosterone, one of the causes of increased body hair and acne in PCOS).

Testosterone is an important hormone both before and after menopause and plays a role in maintaining healthy blood vessels, skin, muscle and bone, breast tissue and the brain. In both women and men, testosterone can act on its own or be converted into oestrogen.

Testosterone naturally and gradually declines by about 25% between the age of 18 years to 40 years, stabilises, then rises a little in the 60’s-70’s. This differs from the sudden change in oestrogen and progesterone that occurs around the menopause.

Interpreting blood testosterone levels is difficult for a number of reasons. Most assays are designed to measure the much higher testosterone levels of men and are not as reliable in women; low levels don’t indicate a lack of testosterone function because much of the hormone is made in the tissues where it is needed (by conversion from pre-hormones); and finally, there is no proven association between low levels and various symptoms in women. As such, there is no such clinical entity as female “testosterone deficiency”.