What Does SPF 50 Actually Mean, and Do You Know Enough About UVA?

Young freckled ginger-haired woman wearing a sunhat and looking into the distance with a smile on her face
Young strawberry-blonde freckled woman wearing a chic sun hat (Image by George Dolgikh from Pexels)

Summer’s almost here. Here’s some info on the meanings of SPF and how to choose the best sunscreen lotion for both UVB and UVA.

A version of this article was originally published on May 18, 2023 in The Road to Wellness on Medium.

I recently heard someone on the radio say that SPF 50 simply means that if you get sunburned in 10 minutes without any SPF lotion, with SPF 50 lotion, it’ll take 50 times that, so 10×50=500 minutes, which is to say about eight and a half hours. It sounded good, but it was by no means accurate, not to mention dangerously misleading: the most protection you can count on is probably about two hours (and much less in the water: 80 minutes for SPF 60).

The radio comment was part of an event meant to raise awareness about skin cancers. They needed sound bites, and this guy provided some. He also said that people who have gotten sunburned when they were young need to be even more careful with their skin.

The FDA fact sheet on SPF explains that SPF is not about the time of exposure to solar radiation but about the amount of UV radiation (in fact, only UVB radiation). Of course, ten minutes at noon is not the same as ten minutes at 10 a.m., and ten minutes at 10 a.m. on a beach in the tropics is not the same as ten minutes at 10 a.m. in New York. So then it follows that you can’t easily calculate the time of solar exposure you can count on these SPF lotions to do their magic.

Also, people have different skin tones, so they take longer or shorter to get sunburned without an SPF lotion.

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In theory, SPF 50 offers 50 times your natural sunburn protection. That sounds better than calculating minutes, but may not be correct either, as I can’t say from personal experience that SPF 15, for instance, is 15 times better than my natural protection, as I burn quite rapidly with it.

But that’s also because SPF 15 lets more UVB rays in from the get-go than SPF 30, and SPF 30 more than SPF 50, regardless of the amount of solar radiation you should be protected from by these sunblock creams and lotions.

SPF 15 blocks only 93% of UVB rays; SPF 30, 96,7%; and SPF 50, 98%.

I notice that empirically because if I use SPF 30 and go out for only an hour later in the afternoon when the sun rays are not all that strong, I return with a slight facial tan. If SPF is a measure of the amount of solar radiation, then SPF 30 should have been enough for an hour’s walking from 5:30 to 6:30 in the afternoon in May in Bucharest. But SPF is not only about x times protection over your skin’s natural defenses against sunburn; it’s also about blocking out a certain percentage of UVB rays.

This is why it’s important to wear strong sunblock even in spring. Okay, I do use lotions with SPF 20 when the sun is not too strong (which is not that great, for reasons laid out below), but for the most part, from spring onward, I rely on SPF 50 if I can help it.

Important: Make sure your SPF lotion protects against UVA rays as well

In the past, SPF sunscreen meant only protection against UVB rays, the ones that burn your skin. But you need to also watch out for UVA rays, which are more stealthy. They don’t cause sunburn, but they penetrate more deeply into the skin, into the dermis, and cause your skin to age more rapidly by affecting the collagen there. Also, just like UVB rays, UVA radiation can cause skin cancer, as it causes free radicals to form, which interact not only with collagen but also with other proteins, lipids, etc., and DNA.

So look for SPF lotions that are “broad spectrum” or have UVA mentioned on the bottle.

But seeing the UVA seal (which means that the UVA protection is at least a third of that given by the SPF number for UVB) or the words “broad spectrum” is not enough. Also, look for these two UVA-PF rating systems:

PA (Protection Grade of UVA). The more plus signs after PA, the better. Look for PA+++ or PA++++

The more Boots Stars, the better. The Boots Stars system is based on the range of UVA protection considered as a percentage of the SPF number. You can have 3, 4, or 5 stars, and 5 stars for a SPF 50 is better, of course, than 5 stars for a SPF 30.

While many of us are aware of the importance of protecting against UVA rays, few of us are aware that this type of UV radiation varies little with the hour of the day and the season and can penetrate clouds as well, which is why we should actually wear sunscreen even when the sun doesn’t seem to shine much, for instance on overcast days. Otherwise, we’ll be saddled with prematurely aging skin. There’s also the risk of cancer to consider with UVA radiation as well, although not as much as with UVB rays.

We’re used to sunblock creams and lotions these days, but unfortunately, we don’t have time to stop and ask ourselves some questions as to how to get the best protection from them: how to choose the best sunblock creams and lotions and why. I hope this article has helped you some in that endeavor so that you’re not automatically reaching for the SPF 50 lotion you’ve used in the past but take a few moments to consider if there may be better options available.

Disclosure: This blog post contains some affiliate links. If you click on (any of) them and make a purchase, they generate revenue for this blog (at no extra cost to you!). As an Amazon Associate I earn from qualifying purchases. All affiliate links on this blog are identified as such. Here’s my Full Disclosure.

Here are two brands and products (or versions of products) I have tried in the past with great results. By great results I mean no visible wrinkles by the age of 38 (see the comments above about the importance of good UVA sunscreens), when I was actually congratulated on it (!) by a classmate at our 20-year high school reunion. I also mean protection from tanning, which I didn’t want after a certain age because I have sensitive skin. A light tan is fine, I want that, but I didn’t want the kind of all-over tan (with the face the same shade as my body) I used to like in my twenties.

I also appreciated these products (or versions of them, because I’ve used only SPF 50 or SPF 50+) because the lotions are very light, non-sticky, and don’t leave a white sheen or a greasy feel on the skin.

Vichy Capital Soleil Anti-Aging Face and Body Sunscreen, Broad Spectrum SPF 60, Water Resistant, Dermatologist Recommended
Vichy Capital Soleil Anti-Aging Face & Body Sunscreen,
Broad Spectrum SPF 60, Water Resistant, Dermatological Skincare
(affiliate image link)
Broad Spectrum SPF 60 sunscreen from La Roche Posay, light fluid lotion, matte finish, non-greasy, dermatological skincare
La Roche-Posay Anthelios Light Fluid Broad Spectrum SPF 60
Face Sunscreen, Ultra Light,
Dermatological Skincare (affiliate image link)

According to La Roche-Posay, their Anthelios products offer a better SPF/PPD ratio than other products. PPD is Persistent Pigment Darkening, another way of referring to protection from UVA rays.

The Vichy Capital Soleil sunscreen also has high UVA protection.

If you decide to travel this summer, or simply enjoy more hours in the sun, I hope you’ll consider getting a really good sunscreen for both UVB and UVA rays.

That’s all for today. I hope you enjoyed this post. If you found it helpful in any way, I’d appreciate a pin/share! Thank you!

To a happier, healthier life,

Enjoy your travels,

🙂 Mira

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