When you’re prone to breakouts, sunscreen may seem like the ultimate Catch-22. You need it to protect your skin from damaging UV rays, but you’re worried it’s going to make zits erupt. We get it. Some sunscreen formulas can be thick and greasy—and that can’t possibly be good when your skin is already oily and your pores are easily clogged, right?

Dermatologists get it, too, but say skipping SPF is not an option. It’s possible to get adequate sunscreen protection without the pimples. We sat down with dermatologist Julie Harper, M.D., founding director of the American Acne and Rosacea Society and an Acne Store advisory board member to learn everything under the sun, about UV protection and sunscreen for acne-prone skin.

Q: First, do you really need sunscreen? Don’t you need the vitamin D?

A: I don’t want you to be a hermit; I want you to go outside to the beach or lake and have a great time. But just as you wouldn’t drive your car without a seatbelt, don’t go out in the sun without adequate sun protection. And, that doesn’t just mean sunscreen. Cover up with hats, sunglasses, and protective clothing, too.

That said, if someone asks me if they need a certain amount of UV exposure, my answer is going to be no. We wouldn’t look at a cigarette and say, “It’s okay to smoke just a little bit,” would we? No. And we know that the UV rays from the sun have a carcinogenic effect on your skin. It’s the leading cause of skin cancer. Yes, you need vitamin D for good health and disease prevention, but why go to a carcinogen to get it when you get it through food sources or a supplement?

And what many people don’t realize is that it’s only UVB rays that are going to give you vitamin D through your skin. And in many places throughout the country and world, we don’t get enough of UVB to get adequate amounts of vitamin D during the cold winter months. So, we should rely on foods and supplements anyway, not the sun.

I don’t think there’s any evidence that UV filters in sunscreen cause acne.

Q: But won’t sunscreen make acne-prone skin more likely to break out?

A: I hear this a lot, but here’s the thing: I don’t think there’s any evidence that UV filters in sunscreen cause acne. It’s more likely the base of the product that can lead to pimples. So, what do you look for? The simplest advice to avoid a sunscreen breakout is to pick an SPF for acne prone skin that is non-comedogenic. That means the formula has been tested to show that it won’t cause early acne lesions called comedones.

I don’t necessarily say to look for an oil-free formula, because not all oils are bad for acne. For example, mineral oil doesn’t have to be avoided. In fact, some prescription acne medications contain some really good oils in them. If your skin is oily on the surface, you might prefer something that has a lightweight feel versus a thicker cream. Or maybe even a spray.

Some people don’t like to use sunscreen because it makes them look shiny. Mattifying sunscreens will certainly help with shine because they absorb some of the oil on your skin’s surface.

Q: What type of sunscreen is best for acne?

A: If sunscreen gives you skin bumps or irritation, look for one that’s labeled ‘for sensitive skin.’ The most common irritants and allergens tend to be fragrance or certain preservatives, and even some of the chemical UV filters such as oxybenzone. Formulas made for sensitive types (such as acne prone or easily irritated skin) are typically made with physical blockers such as zinc oxide or titanium dioxide, which are less likely to cause a reaction. When someone has a breakout or a reaction to sunscreen, they want to throw all of them in the garbage. But when it comes to sunscreens and breakouts, not all formulas are created equal.

Q: I’ve heard sun exposure helps acne. Is that true?

A: This is an interesting question. I think for some people the sun does help their acne. But I’ve always wondered about what else is going on that might contribute to the clearing. When you’re in the sun maybe you’re less stressed. Perhaps, you’re exercising. And stress is linked to acne. So, we don’t know if it’s the sunshine alone that has the beneficial effects.

I also want to tell those people that they’re playing with fire. I don't want to cure your acne and then see you five or 10 years later with skin cancer. So, sun protection is very important even in acne prone skin. Plus, in some people, sun—and all the sweat that comes with it—can make acne worse.

Q: How much sunscreen do I need?

A: A lot. Or at least more than you probably think. Your absolute minimum SPF for acne prone skin should be SPF 30. To get the SPF level on the bottle, you need a shot glass amount, or one ounce, for your entire body. It breaks down to one teaspoon for the face and neck, one teaspoon for each arm, one teaspoon for your trunk, one for your back, and two teaspoons for each leg. So, that’s a good amount of sunscreen. Now, if you’re not in an itsy-bitsy bathing suit, maybe you don’t need to use that much. The most important thing is to cover exposed skin with the right amount.