For decades, scientists have puzzled over the main mystery of acne: If the zit-causing bacteria known as P. acnes lives on everyone’s skin, why do some people react to it with relentless breakouts, while others get to enjoy clear, resilient complexions?

Now, a new study published in the Journal of Investigative Dermatology has discovered a possible answer. Researchers from UCLA lifted P. acnes bacteria from the pores of 49 acne-prone and 52 clear-complexioned volunteers. What they found were more than 1,000 strains of the bacteria, from which they were able to identify genes unique to each strain.And it turns out that all P. acnes was not created equal.

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“We were extremely excited to uncover a strain of P. acnes that’s common in healthy skin, yet rarely found when acne is present,” said principal investigator Huiying Li, an assistant professor of molecular and medical pharmacology at the David Geffen School of Medicine at UCLA.In other words, those with clear skin had “good” bacteria that appeared to keep the “bad” pimple-triggering bacteria at bay, and genetics seem to play a crucial role in who gets doled out the lucky hand.

“Not all bacteria is bad—we have good bacteria in our bodies that keep us in check and help us stay healthy,” explains Joshua Zeichner, M.D., director of cosmetic and clinical research at Mount Sinai’s department of dermatology.It’s a bacterial concept that many women are already familiar with, thanks to the nuisance of yeast infections. But before you slather on a Dannon Light mask the next time you spot a zit, the good news is that scientists already have a lead on potential treatment lotions that won’t have your partner and pets scurrying in the opposite direction.

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Topical creams that contain probiotics, just like the ones found in yogurt, are already commercially available—they just haven’t yet been thoroughly tested for acne treatment.“Probiotic creams have been shown to be anti-inflammatory and antibacterial, and may help rev up the skin’s natural, protective fats,” explains Zeichner. “This research is very exciting—we can learn a lot from yogurt, and further studies on probiotics may help us one day cure acne and countless diseases.”