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Which SPF Sunscreen Should I Use?

July 22, 2025

With so many sunscreen options on the shelves, picking the right one can feel overwhelming. SPF levels, ingredients, sprays versus lotions — it’s a lot to navigate.

If you’re wondering how to choose the right sunscreen, we asked an expert to break down what matters most.

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For most people, SPF 30 is just right.

SPF, or sun protection factor, measures how well a sunscreen protects against UVB rays — the kind that cause sunburns and contribute to skin cancer.

“SPF 30 blocks about 97% of the sun’s rays, and for most people, that’s sufficient,” says Dean George, MD, medical director for Harford HealthCare Cancer Institute’s cutaneous oncology program.

If you’re especially fair-skinned or at higher risk for skin cancer, you might consider SPF 50.

“But beyond that, the added protection is minimal and requires chemical blockers,” says Dr. George

Here’s how different SPFs stack up.

Not sure what those SPF numbers really mean? Here’s a quick breakdown:

  • SPF 15 blocks about 93% of UVB rays
  • SPF 30 blocks about 97%
  • SPF 50 offers around 98%
  • SPF 100 gets you to about 99%

What

“The difference sounds small, but using SPF 30 consistently and correctly makes a big impact,” says Dr. George.

> Related: 12 Dos and Don’ts You Need to Know Before Your Next Sunburn 

Mineral vs. chemical sunscreen: What’s the difference?

There are two main types of sunscreen:

  • Mineral sunscreens (also called physical blockers) contain zinc oxide or titanium dioxide. They sit on top of the skin and reflect UV rays.
  • Chemical sunscreens absorb UV rays and convert them into heat, which is then released by the body.

“Both are effective,” says Dr. George. “Mineral sunscreens tend to be better for sensitive skin and start working immediately. Chemical sunscreens may be more sheer and easier to apply, especially in sprays.”

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How – and when – to apply sunscreen.

“Most people don’t use enough sunscreen or reapply often enough,” says Dr. George.

Here’s what he recommends:

  • Apply a generous layer 15 minutes before sun exposure — about a shot glass worth for your whole body.
  • Don’t forget easy-to-miss spots like your ears, the tops of your feet, your scalp, and the back of your neck.
  • Reapply every two hours, or more often if you’re swimming or sweating.

And remember: Sunscreen isn’t just for sunny days — up to 80% of UV rays can still get through on cloudy ones.

> Related: 5 Risk Factors for Skin Cancer You Should Know

The sunscreen you’ll actually use is the best kind.

Choosing the right sunscreen doesn’t have to be complicated. Whether it’s a spray, stick or lotion, the most effective kind is the one you’ll use — and use often.

“Sunscreen only works if you use it. Find a texture and formula that works for you — and make it part of your daily routine,” he says.