Testosterone in women plays a much wider role in health than most people – and many doctors – realise, a new review of the evidence has found.

Writing in the journal Sexual Medicine Reviews, a team of researchers including Dr Louise Newson examined more than 50 years of research on how women make and use testosterone.

Testosterone is a female hormone too

Testosterone is often thought of as a ‘male’ hormone but is the most biologically active hormone a woman has in her body.

In women, testosterone is produced by the ovaries, adrenal glands, the brain and other tissues. Levels of testosterone are higher than of estradiol when women are younger and usually start to decline when women are in their late 20s and early 30s. Women who have their ovaries removed, or have treatments that affect ovarian function, can experience a more sudden fall in testosterone.

What does testosterone do in women?

The review states that normal testosterone levels help keep bones strong, maintain muscle, regulate metabolism and support healthy blood vessels. Testosterone also plays a part in memory, mood, libido, fertility and reproductive health.

The review also highlights evidence for testosterone's role in protecting the brain, supporting the immune system and maintaining a strong pelvic floor.

Why has testosterone in women been overlooked?

The researchers say long-standing gender bias has meant testosterone's importance in supporting women's health has been neglected for decades.

‘After years of neglect in women patient care, it is time to bring testosterone back into focus, to raise awareness of its diverse physiological functions, and also to elevate the standard of care provided by healthcare practitioners,’ the authors concluded.

Testing testosterone levels in women

Measuring testosterone levels in women is far from straightforward, as levels can fluctuate throughout the day, even when women are using testosterone cream or gel.

Testosterone levels from blood results often cause confusion for both women and clinicians, as a single blood test result can be hard to interpret.

In addition, there are no standardised reference ranges for serum testosterone concentrations in women. This is because comprehensive studies have not been published, and there is constant debate with clinicians regarding testosterone testing and reference ranges.

The authors of this new paper have called for agreed, standardised ways of testing testosterone in women, along with more research to understand what changes in testosterone levels mean for women's health.

Read the full paper here.