My friend Zach, 25, is taking a break from porn. He says his “tolerance” is pushing him to search for edgier smut than before.

“The other day, I took an Adderall and spent 6 hours looking for more and more extreme videos,” he says with a worried expression. It started with your typical teen porn. Then, incest porn. Rough sex. Gang bangs. Rape. A few more he didn’t feel comfortable disclosing. A day devoted to an important work project — lost — because the deadly combination of his laser-focus study drugs and his porn tolerance created a never-ending appetite for newer, more perverted shit.

“It was my rock bottom,” he says.

It’s a widespread belief that we can build a tolerance to porn. I even believed it myself — used it to explain away the disturbing rise of incest porn. It’s not that we really want to fuck a family member, I thought, it’s just our incessant impulse to find edgier smut that can still make us come.

However, researchers have discovered that our ideas about porn tolerance are probably an overblown myth. In a study recently published in the journal "Sexual Medicine," deviants who enjoy watching more hardcore erotica shattered expectations. Just because they loved the kinky stuff, didn’t mean they’d grown bored with traditional smut in the slightest.

In the study, 2,035 subjects were studied for their attraction to mainstream versus non-mainstream porn. Participants were asked how arousing they found 27 different porno categories, ranging from mainstream genres like “amateur” and “vaginal sex” to non-mainstream genres like “fetish” and “bizarre or extreme.”

As it turned out, subjects who were more turned on by the filthy stuff tended to be more aroused by all categories of porn. It’s not that they couldn’t get horny from your standard vanilla “naughty teacher” narrative, and needed to upgrade to something with more pain and humiliation. All types of naked movies got them all hot and bothered.

Researchers also wanted to find out if fans of non-mainstream pornography thought their sexual interests were less healthy — or if they were any less sexually satisfied. Negative. The perverted participants didn’t feel guilty for their deviant desires, or let stigmatization get in the way of their sex lives.

At this point, it’s important to note that the porn tolerance study didn’t take place in the United States. If it had, the subjects would likely feel far guiltier about their unconventional sexual interests.

The sex-negative culture in the U.S. has fueled an American hysteria of porn addiction, in which people believe the amount of porn they’re watching is excessively unhealthy, even when they’re watching less porn than the average person.

Twelve-step programs like Sex and Love Addicts Anonymous aim to cure porn addicts of a dependence they believe is as destructive as hardcore drugs, while religious movements like Porn Kills Love place billboards along your commute to make you feel like a shitbag for jerking off.

America’s puritanical society also likely explains why Zach considered his drug-fueled day of masturbation “rock bottom” instead of “six hours of sheer ecstasy.”

Emerging science indicates it’s not possible to build up a tolerance to porn — so if study drugs ever take you down the road of relentless masturbation, don’t swerve off the road. Just enjoy the ride.