Testosterone is the only agent known to improve desire and arousal in women, with results from a new international trial suggesting the benefits in the bedroom are ''very substantial''.

Sexual health specialists have welcomed the findings as a gift for post-menopausal women who have a flagging sex drive but the desire to make it work.

Professor Basil Donovan, from the University of Sydney, says, ''For a lot of women, the flower of their sexual career is often in their post-menopausal years when they're no longer busy with work and have met the man they want to be with, and this may be just what they need.''

The study, published in The New England Journal of Medicine, involved 814 post-menopausal women worldwide who were given either the male hormone or a dummy patch which is stuck to the stomach

The women enjoyed half their sexual encounters before the study, according to lead investigator Professor Susan Davis, from Monash University. ''But afterwards women who used the patch experienced twice the number of satisfactory events than women using a placebo patch.'' AAP