What is testosterone?

Testosterone is an important hormone in women which is derived from the ovary as well as the adrenal glands. The blood level of testosterone is higher than the oestradiol in young women in their 20s, and there is a gradual decline with age.

Why is testosterone important?

The value of testosterone was first recognised by Professor Greenblatt in 1950. He reported that women with persisting sexual difficulties can benefit from the addition of testosterone. This was confirmed by studies carried out by Professor John Studd in the 1970s who reported that women taking oral oestrogen replacement therapy with persistent sexual difficulties will benefit from oestrogen and testosterone given as subcutaneous implants. He also observed that blood tests are unhelpful in assessing which women can benefit from testosterone treatment, though blood tests are useful for monitoring treatment. A clinical assessment is essential therefore before prescribing testosterone for loss of libido because it may not always be hormonal. It may be due to relationship problems, or because of a reduction in general well-being, poor sleep, tiredness, depression and vaginal dryness which can make penetrative sex painful.

Testosterone receptors have been identified in areas of the brain which affect and control mood. John Studd also reported that testosterone treatment can help with symptoms other than a loss of libido, including general well-being, tiredness, depression and headaches.

Use of testosterone treatment

A recent publication reviewed the more recent studies on the use of testosterone in women and confirmed that testosterone can help with loss of libido but stated that there was insufficient evidence that it can help with any of the other symptoms. However, this report was very largely based on industry-funded studies using the testosterone patch which has since been withdrawn from the market (for commercial, not medical reasons) and used sexual function as the endpoint. They often excluded women with depression and were therefore not adequately powered to assess the impact of testosterone on other symptoms. Earlier studies not included in this report demonstrated that the addition of testosterone to oestrogen resulted in a further improvement in general wellness and psychological symptoms as well as libido.

Women prescribed  testosterone as part of their HRT will need to have a blood test, after three months and then every 12 months to check that their blood levels are in the normal range.

Safety of testosterone

Testosterone is safe. Heart disease is more common in men than women and it was therefore assumed that this was due to testosterone. In fact, the evidence seems to suggest that testosterone can protect against heart disease. Men with low testosterone are at increased risk of heart disease and women with low testosterone may also be at increased risk too. A recent study from Australia indicates that women with higher testosterone levels have a higher beneficial HDL cholesterol and reduced triglycerides.

Testosterone can very rarely lead to a slight increase in hair growth or acne but this not often a problem and resolves when the dose is reduced or stopped.

There is no evidence that testosterone has any impact on the risk of breast cancer. Not all women receiving HRT require testosterone, but it should be considered in women with persistent menopausal symptoms despite adequate oestrogen replacement.