Professor Susan Davis is a women’s health researcher. In 2005 she became the inaugural Chair of Women’s Health in the Monash University Department of Medicine at the Alfred Hospital in Melbourne, Australia. In addition, she is a consultant endocrinologist at Alfred Health and Cabrini Medical Centre, also in Melbourne.
Professor Davis has been involved in the study of the role of estrogens and androgens (e.g., testosterone and DHEA) in women. She has been investigating the effects of hormones throughout the body, rather than just how they affect reproductive functions. She has published over 300 peer-reviewed articles. She is indeed a giant in the world of research involving the use of testosterone in women.
In December of 1999, Dr. Davis published a commentary on the nature of testosterone replenishment in women. Almost 20 years has passed since this commentary was published, yet not much seems to have changed. Scientists and physicians are still unclear on what actually constitutes a deficiency of testosterone in women. The clinical picture of a woman with adequate testosterone has not been established or agreed upon. There is no agreement on how low testosterone levels must be before action is taken.
The following is a brief synopsis of a number of subjects taken from Dr. Davis’s commentary.
Declining Testosterone in Women
It is well established that testosterone and DHEA production steadily declines with aging. There are also a number other reasons testosterone levels may be low:
- 50% of testosterone production is lost when the ovaries are removed (oophorectomy) as part of a “complete hysterectomy.”
- Chemical damage to the ovaries produced by chemotherapy in cancer treatments.
- The use of estrogen only hormone therapies and oral contraceptives. Both increase sex hormone binding globulin (SHBG), which binds testosterone and prevents the body from using it.
- Treatment with corticosteroid drugs like prednisone turns off the production of adrenal testosterone. This may be the cause of osteoporosis when using these drugs. It has been established that the best bone mineral density levels are associated with strong levels of testosterone and DHEA.
- Premature ovarian failure.
- Loss of cycling due to lost signaling from the hypothalamus.
It has been established that adequate testosterone levels are associated with sexual interest in a way that estrogen levels are not. However, because sexuality is complicated and multi-faceted, using libido and sexual activity as distinct markers for adequate testosterone levels is not reliable. One should also consider vaginal atrophy, pain during intercourse (dyspareunia), loss of interest in a partner, or other psychological factors as contributors to sexual dysfunction.
Bone loss may continue to occur even with estrogen and progesterone supplementation. When testosterone supplementation is added, bone growth may be restored. Some suggest that testosterone acts as a prohormone for estrogens and that this interplay must be in effect for good bone health.
In general, muscle mass declines in the elderly and fat mass increases. Testosterone has been demonstrated to improve muscle mass in postmenopausal women. Additionally, testosterone has been effective in restoring muscle mass in both immune compromised men and women.
Women are more prone to autoimmune diseases. It has been theorized that the higher testosterone levels enjoyed by men contribute to this gender difference. Testosterone replacement has been used successfully in diseases such as autoimmune rheumatoid arthritis.
Premenstrual Syndrome (PMS)
Below average levels of circulating testosterone have been identified throughout the entire menstrual cycle in some women who have PMS symptoms. In Australia and the UK, testosterone has been used for treatment of PMS.
Other Consequences of Testosterone Deficiency in Women
In 2015, Dr. Davis published another review article. She added cognition, cardiovascular health, vaginal integrity, and pain relief to her documentation. She cites numerous studies about the anti-proliferative effect of testosterone in breast and ovarian cancer, but points out it is difficult to draw conclusions without considering the effects of multiple other hormones, including estrogens. In spite of testosterone being a much more prevalent hormone than even estrogen in women, we still don’t know much about its effects. Dr. Davis says that research in women lags about ten years behind where it should be. Too many studies are small and limited in their scope, making solid conclusions impossible.
In spite of several attempts to obtain FDA approval for gels and patches delivering testosterone replenishment for women, nothing has been approved. This appears to be due to a lack of consensus on the function of testosterone in women. However, testosterone has been available to women for decades with the assistance of compounding pharmacists. Testosterone can be prescribed in oral capsules, creams, gels, suppositories, drops, troches, pellet implants, and injectables. Thanks to compounding pharmacies, practitioners may choose to treat each of their patients’ testosterone deficiencies and monitor the effects — one patient at a time.