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We Were All Wrong About the Post-Sex Refractory Period

Science blamed a specific hormone for our inability to get hard again — but we never had the evidence to prove it

If ever you’ve bemoaned the penis’ inability to go for round two right after round one and taken to Google for answers, well, you’ve probably been bamboozled. For years, the refractory period has been thought to be caused by prolactin, a hormone responsible for such bodily functions as breast growth and milk production. Given that studies have found that men release prolactin upon ejaculation, it seemed like the appropriate culprit behind the need to take a break. Turns out, that’s all wrong. Hopefully you didn’t invest in any prolactin-suppressants recently! 

According to research published this month in Communications Biology, we’ve long been relying on this theory without much actual evidence to support it. In the study, scientists at the Champalimaud Centre for the Unknown in Portugal attempted to support the theory by measuring prolactin levels at different stages of sexual behavior in mice, whose stages are quite similar to humans. 

The researchers then manipulated prolactin levels in mice by increasing their hormone levels prior to sexual arousal to what they would be during the act itself. If the idea of the refractory period being caused by prolactin were true, then the prolactin would cause the mice to not want to bone to completion. This, however, wasn’t the case: Despite being dosed with prolactin, the mice still went at it. 

Following this, the researchers also tested whether blocking prolactin entirely would cause the mice to be even more sexually active, but again, no changes occurred. 

If these theories about the connection between prolactin and the refractory period aren’t true, then what is prolactin in males even for? 

We’re still not exactly sure, though previous studies have suggested that prolactin may help establish parental behavior in men just as it does in women after childbirth. 

There’s also some evidence that prolactin does indeed play a role in sexual dysfunction, as chronically high levels of prolactin and decreased sex drive have previously been linked, and prolactin-blocking treatments have been effective in remedying it. But as for men who have no problem finishing the first round of sex and are just eager to go again for another, manipulating your prolactin levels probably won’t do anything for ya. 

You’ll just have to be patient.