Scientists find no proof that testosterone eases menopause brain fog, while some women pose as men to get prescriptions online

A UCL review of five studies, covering 244 post-menopausal women with an average age of 57, found no significant improvement in cognitive function among those given testosterone over periods of four to 26 weeks. Professor Aimee Spector, the study's senior author, said more research is needed before any claim can be made that the hormone improves cognition during menopause.

Researchers stressed the findings show insufficient evidence to establish an effect, not proof that testosterone does nothing.

Dr Alexandra Faulkner, of UCL's Division of Psychology and Language Sciences, said the existing evidence is too thin to draw conclusions about testosterone's true effect.

Social media is stoking demand for the hormone, and some women have gone so far as to pose as men in order to obtain prescriptions online.