The commercially available assays for total and free testosterone were developed for the measurements of much higher circulating concentrations in men; these assays have generally lacked the sensitivity and precision required to accurately measure the lower levels of testosterone in older women.
There has been a paucity of normative data on testosterone levels in menstruating women, older women and women with chronic illnesses; this has made it difficult to define androgen deficiency in women in precise quantitative terms. The available formulations for androgen administration were developed for the replacement of much higher doses required for the treatment of hypogonadal men. Very little pharmacokinetic data exist on the bioavailability and clearance of androgens delivered from the available formulations in women. Therefore, it is not surprising that many previous clinical studies in women used pharmacological doses of testosterone in relatively unphysiological experimental paradigms.
The objective of physiologic testosterone replacement is to restore serum total and free testosterone concentrations into a range that is mid-to high-normal for healthy, young women. Testosterone regimens that increase serum testosterone levels into the supraphysiological range should be viewed as pharmacologic.
Sexual dysfunction in women, a highly complex, multi-factorial issue, has become synonymous with androgen deficiency in the lay press. Observations that pharmacological doses of testosterone might improve sexual function in subsets of women with sexual dysfunction have been unjustifiably extrapolated to advocate testosterone replacement as a general treatment for sexual dysfunction in older women.
It would be incorrect to assert that testosterone supplementation of older women has no role in clinical practice; on the other hand, the available data do not warrant a general recommendation for testosterone replacement for all post-menopausal women.
Link to article: http://www.goodhormonehealth.com/symptoms/androgen.pdf