Lovers know only too well that men usually need a “recovery period” after orgasm, and that sexual intercourse with orgasm is more satisfying than an orgasm from masturbation alone. Now scientists think the two phenomena might be linked. After orgasm from sexual intercourse, the increase in blood prolactin (a hormone released after orgasm) levels is 400 per cent higher in both sexes compared with after orgasm from masturbation. The hormone prolactin makes us feel satiated by countering the effect of dopamine, which is released during sexual arousal.

The researchers measured blood prolactin levels in male and female volunteers who watched erotic films before engaging in masturbation or sexual intercourse to orgasm in the laboratory.

This explains why orgasm from intercourse is more satisfying than masturbation. Since elevated levels of prolactin have been linked to erectile dysfunction, this may also explain why most men need a recovery period after sex. The study appeared in Biological Psychology, vol 71, p 312.