If you’re single and ready to mingle, you’re probably swiping left and right. The modern dating scene is as much entrenched in mobile apps as the rest of our lives, and these apps–Tinder, Bumble, Grindr, OKCupid–spur users to make snap judgments as they cycle through hundreds of potential matches. In this kind of fast-paced, hot-or-not environment, everything counts. Pictures have to be perfect, displaying your best assets. And of those assets, nothing gets scrutinized more than hair. Its color, its shape, its length… everything is weighed in milliseconds as fickle thumbs dangle above you.

We’re fascinated by how much hair can help or hurt you, so we’ve conducted a study of single swipers to see what gets them swiping right to say “Hey” or left to say “Nay.”

Brace yourselves: the dating world does not take kindly to redheads. Especially men. Red-haired men are the most universally reviled creatures, with 62% of people attracted to men saying they think red hair is the worst. To put that in perspective, the next most hated hair color is blonde, selected by a mere 16% of people attracted to men. On the flip side, brown hair is adored, with 56% of people attracted to men preferring brown above all else and 43% of people attracted to women feeling the same way.

When it comes to hair style, straight women and gay men both prefer crew cuts above all else. Straight women prefer them four times as much as the next most preferred style (messy) and gay men prefer them three times as much as the next most preferred style (undercut).

Our survey wouldn’t be complete without grabbing some data on facial hair, that polarizing outgrowth of so many man faces. The most important takeaway: hipster beards ain’t so hip. Of people attracted to men, 46% think long beards are the worst, while more than a quarter think a five o’clock shadow is most attractive.

We know looks aren’t the most important thing, and people are rarely looking for someone who’s fussy about their hair. But if you’re gonna throw your hat in the ring and compete in the online dating, it helps to know what the people wants. Good luck!