'Cuddle drug' may be the new Viagra

Nasal spray of hormone used to induce labour can dramatically improve sexual performance in men

It is the chemical that has been described by women as a "cuddle drug". Now scientists have discovered that its effect on men is more rampant and long-lasting than just the desire for a quick hug.

Oxytocin, a hormone traditionally used to induce labour, is as sexually arousing to men as Viagra, according to new research.

Studies conducted in the US found that a married man who sniffed a nasal spray containing oxytocin twice daily became more affectionate to friends and colleagues and recorded a marked improvement in his sexual performance.

According to the actual breakdown of results, the man's libido went from "weak to strong", while arousal went from "difficult to easy". Ego certainly wasn't hurt either: sexual performance, according to feedback from his wife, was classed as "very satisfying".

Scientists at the University of California believe the findings provide strong support for the idea that oxytocin improves sexual performance and, unlike Viagra, remains a chemical glue within the brain to cement relationships between people. Just how it works is not clear, but some studies have suggested that oxytocin levels rise naturally during arousal. The hormone is also thought to interact with the dopamine system, which is involved in the rewarding aspects of sexual activity.

Dr Mike Wyllie said: "Given the number of erectile-dysfunction patients who don't respond to drugs like Viagra, there is a great medical need for a new class of drug; this case study suggests there is a basis for optimism that this is achievable. Assuming positive clinical trials, a drug based on this approach could achieve blockbuster potential."

Oxytocin is produced mainly in the hypothalamus region in the brain, and has been most widely studied in women. It's released during labour to dilate the cervix and boost contractions, and also triggers the release of milk in the breasts. More recently it has been shown to have wider effects on behaviour, including boosting trust, co-operation and bonding, and it has been investigated for a number of conditions including anxiety and autism.

The new study, "Dramatic Improvement in Sexual Function Induced by Intranasal Oxytocin", was reported in The Journal of Sexual Medicine.

Oxytocin's power was first recognised in 1979 when virgin female rats whose brains were injected with the hormone began to display maternal behaviour. Since then, several hundred research studies have been carried out, shedding light on the hormone's role in the early stages of sexual passion and in the process of mother-child bonding after birth.