History of Testosterone Use in Females
There is universal acceptance amongst reproductive endocrinologists, gynecologists and those specializing in the area of women's health that females' sexual dysfunction affects a substantial proportion of women. This has significant psychological ramifications and can adversely affect social and personal relationships. Various studies indicate that between 30-43% of women aged between 18 and 59 years of age experience some degree of sexual dysfunction.
Classifications and defining criteria for sexual dysfunction in women have been established over the past few years. Validated assessment scales and questionnaires have been developed to assist with the diagnosis and monitoring of management regimes for sexual dysfunction .
Female sexual dysfunction is a multifactorial condition that requires careful evaluation and may involve several management strategies. The hormonal profile of the subject is part of the assessment to determine the origins of sexual dysfunction.
The hormone testosterone has greatest influence on human sexual function.
Testosterone is a vital component of female sexuality, enhancing interest in initiating sexual activity and response to sexual stimulation. It is also the hormone associated with greater well-being, with increased energy and vitality and with reduced anxiety and depression.
Surgically menopausal women and women with premature ovarian failure are among the populations most likely to experience a testosterone deficiency, a syndrome characterized by blunted or diminished motivation; persistent fatigue and lethargy; decreased sense of personal well-being; low circulating blood testosterone levels and low libido.
In contrast to estrogens serum androgen levels do not fall precipitously at the time of menopause, but rather decline with age particularly after the age of 40. Total testosterone levels in women in their forties are approximately 50% of those of women in their twenties.
Early scientific evidence showing that testosterone is the libido enhancing hormone in the human female was reported during the 1940's and 50's.
It was in the mid-1970's that the vital role of the ovary in testosterone production was established. Subsequent research has established that sexual function declines following oophorectomy (surgical removal of the ovaries). Additional research has established that administration of testosterone reversed the decline in sexuality as a result of oophorectomy.
Prior to 2000 the majority of medical research conducted with testosterone use in women had centered on testosterone implants and injections. While therapeutically effective, these dose forms have significant shortcomings when used in women.
They produce extremely high serum levels in women even when administered in reduced doses (often 10 times higher than normal levels) and have the potential for causing significant side effects including masculization, hirsutism (body hair growth), acne and voice changes.
Many women who suffer from loss of libido date their problem to removal of their ovaries. This surgery in both pre and postmenopausal women results in an immediate 50% reduction in circulating serum testosterone levels.
Standard medical practice over the past 40 years has been to supplement women with estrogen after removal of the ovaries, but ignores the hormones testosterone and progesterone.
Estrogen therapy alone usually does not restore libido in oophorectomized women. Medical studies comparing estrogen alone with estrogen plus testosterone have shown a significant improvement in energy and libido with the combined treatment without side effects. Additional medical trials have also shown testosterone has an additive effect on bone density when combined with estrogen - a very important consideration for prevention of osteoporosis.
The problem of reduced libido and unexplained fatigue is not confined to women who have undergone surgical removal of the ovaries (oophorectomy).
Pre and postmenopausal women with intact ovaries also can have low testosterone levels and experience the same symptoms for low sexual desire and lethargy as oophorectomized women. Small doses of testosterone can result in significant improvements in the quality of life and sexual fulfillment of these women.
Despite the fact that no testosterone product has been approved in the USA or Europe for the treatment of poor libido in women, male approved testosterone products are usually given to women in reduced doses. This is common place by doctors around the world - a practice called "off-label" usage.
The two most popular products worldwide that are used in women off-label are injectable testosterone (typically Sustanon®50 mg monthly) or testosterone implants.
There are no published trials using injectable Sustanon in this way.
Typically two or three injections of Sustanon improve energy and libido, the patient is then offered testosterone implants (50 to 100 mg dosage) every 6 months, in conjunction with HRT.
Insertion of testosterone implants requires a minor surgical procedure which typically involves a local anesthetic, a small incision (about 1cm) and the use of a trocar (a wide tube) to insert the implant deep into the fat tissue. About 10% of testosterone implants are expelled and there is a small risk of infection. Current clinical practice does not encourage the long-term use of injectable testosterone, as it has been noted that some patients have developed significant excess hair using injectables typically in a dosage of at least 100 mg Sustanon monthly for at least 6 months.
Injectables tend to produce high peak levels but are a useful form of testosterone therapy as an initial 'trial' to monitor patient response to testosterone therapy.
The situation in Australia is distinctly different with a 1% testosterone cream (AndroFeme® Lawley Pharmaceuticals) available for use in women. AndroFeme®is by far the most popular testosterone treatment option for use in women because it involves no surgery, no pain, is applied by the woman in the privacy of her own home and the dose is accurately controlled.
Since the year 2000, the pharmaceutical industry has developed and trialled a significant number of testosterone delivery systems for use in testosterone deficient females.
The transdermal testosterone patch, Intrinsa®(Procter and Gamble, USA) and the topical testosterone cream (AndroFeme® Lawley Pharmaceuticals, Australia) lead the way in this exciting area of female healthcare.