A HORMONE in chocolate could boost men’s sex drive, says research.

Males injected with the protein kisspeptin got more turned on by sexual images in tests.

They reacted less to negative or neutral pics.

They were also scored on questions about sexual aversion, and arousal.

Dr Alexander Comninos, of Imperial College London, concluded: "We have conducted previous studies that showed kisspeptin can activate specific brain areas involved in sex and emotions.

"However, this study enhances our knowledge of the hormone even further.

"Our findings suggest it can actually influence entire networks in the brain even when we are not doing anything and this is linked to subsequent sexual and emotional function."

Dr Comninos said: "Our findings help unravel the many and complex roles of the naturally-occurring hormone kisspeptin, and how it orchestrates reproductive hormones as well as sexual and emotional function.

"Psychosexual problems, such as low sex drive, affect up to one in three people, and can have a devastating effect on a person's, and a couple's, wellbeing. These findings open avenues for kisspeptin as a future treatment for these problems, although there is a lot of work still to be done."

Prof Waljit Dhillo, of Imperial College London, said: "Although we have previously investigated how this hormone affects the brain when it is in an active state, this is the first time we've demonstrated it also affects the brain in its baseline, resting state. These insights suggest the hormone could one day be used to treat conditions such as low sex drive or depression."