Q: What are 'normal' levels of testosterone in women?

A: There is often a delusion amongst patients that testosterone is a male hormone. Of course it is a normal female hormone but it is not always understood that in healthy young women it is present in 10 times the level as oestradiol. Similarly there are many more Androgen receptor sites in the female brain than oestrogen receptors. Androgen levels begin to decline at the age of 20 and by the time of the natural menopause the levels are much reduced. Everyone is aware that oestrogen levels fall with the menopause but there is also a 50% fall of testosterone after a natural menopausal and a 75% fall in testosterone after bilateral oophorectomy. -- Professor of Gynaecology, John Studd, Testosterone in Women