Women normally have circulating in their blood three major sex hormones: oestrogen, testosterone and progesterone. Each of these is produced by the ovaries. Oestrogen is also made throughout the body but particularly in body fat. Testosterone can be made by the adrenal glands and in other parts of the body from hormones (DHEA and DHEAS) that are produced by the adrenal glands. At the time of natural menopause or surgical removal of the ovaries, oestrogen and progesterone levels fall precipitously.

Testosterone and DHEAS levels fall gradually with increasing age; so that a woman in her forties has on average only half of the testosterone and DHEAS circulating in her bloodstream as does a woman in her twenties. After a woman has her ovaries removed by surgery, testosterone levels can fall by up to 50 per cent. However testosterone does not change across menopause, although this varies somewhat between women.

Testosterone and other related hormones (DHEA and DHEAS) in the body, also known as androgens, have known physiological roles in women. Firstly, oestrogen is actually made from testosterone and DHEA, and without the ability of our bodies to make testosterone we cannot make oestrogen. Testosterone and DHEA appear to have direct, independent effects in different parts of the body. Some women may experience a variety of physical symptoms when levels of these hormones in their blood fall. Such symptoms may include:

• Impaired sexual interest (loss of libido or sexual desire), and lessened sexual responsiveness
• Lessened wellbeing, loss of energy

Testosterone therapy may be beneficial for some women who have had their ovaries surgically removed or in some who have significant symptoms in the form of loss of libido, fatigue and diminished wellbeing.

Caution 

Testosterone therapy will not be the answer for someone who has a poor partner relationship, depression or poor wellbeing due to other causes.

Measuring testosterone

All women should have a blood test, preferably in a laboratory which uses a sensitive assay specially adapted to use in women, to measure their testosterone level before starting any testosterone replacement - mainly to exclude higher levels of testosterone. There is no set lower level of testosterone that suggests or guides treatment, but it is essential that women with normal or high levels are not misdiagnosed and treated with androgens. Women should have thyroid disease and iron deficiency excluded as possible causes of their symptoms by having a blood test for these conditions.

Most methods for measuring testosterone are fairly imprecise and become even more inaccurate when blood levels of testosterone are low. Blood should be taken ideally between 8:00am and 10:00am as testosterone levels vary throughout the day. For women who have regular cycles, blood should not be taken during the menstrual phase as testosterone levels are low at this time in most women and thus the result may be misleading. Blood should be drawn at least eight days after the start of menstruation.

Research at the Jean Hailes Foundation for Women’s Health has shown no relationship between testosterone levels and loss of libido or sexual dysfunction, in a community-based sample of women who had no concerns about their general or sexual health. This study has provided an important database for the normal ranges of testosterone as a function of age. Women with levels around or below the lower limits of normal for their age can be assessed as having levels consistent with but not diagnostic of androgen deficiency. In the presence of a history of unexplained fatigue, together with loss of libido for which no other cause can be identified, such low levels would support the diagnosis of possible androgen deficiency, which may warrant a trial of testosterone treatment.

The factors that do influence libido are discussed by psychologist Dr Mandy Deeks PhD in her "10 tips for understanding and improving your libido". It is important to note that for many women sexual desire occurs only in response to an appropriate stimulus – so-called Responsive Desire.

[More information is available at Libido]

For those women with persistent low libido in whom lifestyle and relationship issues have been addressed, testosterone therapy may be appropriate. Therapy may improve libido, especially in oophorectomised women. However with libido and testosterone therapy in women, there are areas that need further research, these include:

• Defining the clinical features of androgen insufficiency in women
• Appropriate testing/investigation
• Appropriate testosterone preparation availability for women
• Safety data on longer-term use

If testosterone therapy is used

Testosterone can be taken as tablets, by injection, as an implanted pellet, as a cream, as a skin patch (unavailable in Australia), gel or spray (not yet available).

Currently no form of testosterone therapy is officially approved in Australia by the Therapeutic Goods Administration for women. However, testosterone has been used for many years in public hospital specialist clinics and in private practices to treat postmenopausal women with low testosterone levels. Decisions on use need to be made in partnership between women and their doctors.

For many years the most commonly used form of therapy for women has been with a testosterone implant pellet. This is a very small pellet which is implanted in the fat of the front lower abdomen, using a small incision (less than 1 cm). The procedure takes approximately 10 minutes to perform. The pellet releases testosterone over a period of three to six months, after which time it needs to be replaced. We most commonly recommend the use of 50 mg of the testosterone implant, although rarely 100 mg is required.

Testosterone tablets (e.g. Andriol^®) are available on prescription, but they are only available in a dose form developed for men, and much less is known about their action in women or about what is the most suitable and effective dose. Blood levels vary widely after tablet use. The use of testosterone tablets by women cannot be recommended.

Testosterone injections can also be used, but these result in very high levels of testosterone as they were developed for use in men, and little is known about the actual release dynamics of the injections in women. Their use cannot be recommended.

Testosterone skin patches have been developed and are now undergoing research trials to address their safety and efficacy. Similarly, studies are underway to evaluate the safety and effectiveness of a testosterone gel and a skin spray in women.

A testosterone cream named Androfeme^® is available in Western Australia that has been approved by Western Australian health authorities for use in women. This cream has been used in some short-term studies, but there is no long-term safety information regarding the use of this or any other form of testosterone cream.

Some physicians and pharmacists are promoting the use of testosterone and DHEA (another androgen) in the form of lozenges (also called troches), which are sucked in the mouth or given as creams. These have been labelled as being 'bio-identical'; however, they are no more bio-identical than the other forms of testosterone that are available or undergoing research. The lozenges result in extremely high blood levels of testosterone, well above those appropriate for women. There is no research evidence that they are safe or even effective, and their use cannot be recommended.

A recent well-designed trial of two years of DHEAS therapy suggests no benefits on wellbeing, libido, sexual function, cardiovascular risk factors and other ageing related endpoints. More research is needed. DHEAS is currently banned from importation into Australia and is not approved for use.

Side effects of testosterone treatment

Short-term side effects of testosterone therapy appear uncommon when testosterone is used in appropriately selected women and given in the appropriate dose. However, side effects will occur in any woman if the dose of the testosterone is in excess of her needs. Such side effects include masculinisation with acne and excess body hair, scalp hair loss, fluid retention, deepening of the voice, enlargement of the clitoris and adverse effects on blood cholesterol. It is our experience that these side effects are rarely encountered if the appropriate dose of testosterone is administered and blood levels are regularly monitored.

Women with severe acne or severe excess body hair or with thin scalp hair should not use testosterone. Women with very low levels of SHBG may be at increased risk of side effects of testosterone and therapy should be used very cautiously with careful monitoring.

Similarly, testosterone should not be used by women who are pregnant or lactating or who have a suspected cancer. Some studies have shown that high levels of testosterone are more common in women who develop breast cancer; however, the data to indicate any association between testosterone replacement and breast cancer are controversial.

Testosterone levels must be monitored during treatment, and blood levels achieved with therapy should be kept within the normal range for women.

Warnings

• Any woman using testosterone during child-bearing years must have reliable contraception as testosterone may result in virilisation of a female foetus if it is used after conception
• All women using testosterone cream should have a blood test after three weeks use and should be reviewed at six to eight weeks by their doctor
• No woman should continue treatment beyond six months if a clear benefit has not been achieved
• There is no information regarding the safety of the use of testosterone in women long-term
• Testosterone is not currently approved for use in women by the TGA and FDA pending further research

Further resources:

International Menopause Society (IMS) recommendations on postmenopausal hormone therapy

Content updated July 19, 2011