What SPF sunscreen should you use?

Store shelves are lined with sunscreens touting 15, 30, 50, even 100 SPF, but the higher the number doesn’t always mean you’re getting better protection. In fact, it can even give you a false sense of security that leaves you with a nasty burn. So what number should you aim for? We’ve got the lowdown.

Sun protection factor, or SPF, is the way we measure how a sunscreen protects you from UVA and UVB rays from the sun. Specifically, it’s a measure of how long it would take your skin to burn from UV rays. Let’s say it would take you one hour for your skin to burn without any kind of protection on it. With SPF 30, it would take 30 hours if you applied it perfectly. With SPF 50, it would take 50 hours and so on. 

That’s not a real-world metric, however, because SPF protection is measured in a lab setting with perfect application and regularly reapplying the sunscreen. A bunch of factors, like sweat, water and oils on your skin, affect how long a sunscreen stays on your skin to protect it.

What SPF should you buy? 

Various health authorities have different recommendations, though all agree that SPF 15 is the minimum. For the best protection when you’ll be outside all day at the pool, park, beach, amusement park or elsewhere, SPF 30 or higher is ideal.

 Here’s what the major health authorities say:

All of those authorities agree that you should be using a broad-spectrum sunscreen, which protects your skin against both UVA and UVB rays. Make sure any sunscreen you buy clearly states that on the bottle.

What’s the deal with SPF 100?

At some point around the early 2000s, brands started to one-up each other by putting out sunscreens with higher and higher SPFs, until we reached 100. 

A study published in the Journal of the American Academy of Dermatology in late 2017 seemed to confirm that we should all be buying the highest SPF possible by concluding that SPF 100-plus was more protective against sunburn than SPF 50. 

Then, in 2019, another study published in JAAD produced similar results when tested in a beach vacation setting, showing that SPF 100 was more protective against sunburn than SPF 50.

Still, some experts argue that SPF 100 sunscreens only offer a marginally higher level of protection than SPF 50 — specifically, SPF 50 blocks 98% of UV rays, while SPF 100 blocks 99%. Not only that, but a high SPF sunscreen can give you a false sense of security, which might make you feel like you don’t have to reapply sunscreen as often as you really should.

If you are particularly prone to getting sunburn, getting a sunscreen with SPF 100 might be worth it. However, according to the major health authorities, most of us will do just fine with SPF 30 and above. 

Regardless of what SPF you use, you still need to reapply every two hours.

Sunscreen guidelines for everyone to follow:

1. Everyone should wear sunscreen, regardless of your skin color, because anyone can get skin cancer.

2. Sunscreen protects against both UVA and UVB skin damage and wrinkles.

3. Both chemical and mineral sunscreens are considered effective and safe by the FDA.

4. All sunscreens, regardless of SPF, can rub off or break down on your skin in the course of two hours — even faster if you’re swimming or sweating. That’s why no matter what SPF you use, you need to reapply sunscreen every two hours to get the full protection.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.