No matter how high their libidos, most men simply can't have sex a second time after having an orgasm without a bit of a break, and that's long been blamed on a pesky hormone called prolactin.
There are even (non-FDA-approved) treatments to that claim shorten the so-called 'refractory period' by reducing levels of this hormones.
But a new study brings bad news for men who thought they'd found the secret to a second round: prolactin may not be the problem after all, a new study in mice suggests.
Researchers at the Champalimaud Centre for the Unknown in Portugal found that neither boosting nor cutting prolactin levels in mice of several different species changed their typical refractory periods.
Alternative theories suggest hormones and feel-good hormones like oxytocin, serotonin and dopamine are involved, scientists still don't know what causes the male refractory period or how to shorten it - and now the most promising explanation seems to be falling flat.Insurance Loans Mortgage Attorney Credit Lawyer
While women can have sex multiple times in a row and even orgasm multiple times n a row, the vast majority of men have to wait some period of time before they can be aroused enough for sex or orgasm.
It's long been assumed that a spike in the hormone prolactin causes men's post-sex refractory period - but new Portuguese study suggests that the hormone has nothing to do with the wait for round two (file)
That changes with age, as well as other factors like stress levels.
Refractory periods for 18-year-old men only last about 15 minutes on average, while a man in his 70s will likely need all day - about 20 hours - before he's ready to go again.
Why men have to wait has never been fully worked out.
But decades ago, scientists noticed a common theme among male humans and animals who had post-orgasm refractory periods.
In men and other mammals, the hormone prolactin spiked right around the time of ejaculation.
Plus, men with generally low sex drives, who struggle to orgasm or to ejaculate also have chronically high levels of prolactin.
In the absence of a better explanation, the link became cultural cannon.Insurance Loans Mortgage Attorney Credit Lawyer
'These different results all point towards a central role for prolactin in suppressing male sexual behavior,' said Dr Susana Lima, corresponding author of the new research, which was published Monday in the journal, Nature.
Like most hormones, prolactin serves a number of