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spf meaning

SPF, PPD, PA+, UVAPF: What Does Your SPF Label Actually Mean?

SPF, PPD, UVAPF, PA+, the UVA Circle…what’s behind your SPF meaning? We break it down below.

As consumers have started buying sunscreens from abroad, they’re now being confronted with a confusing choice of UV protection labels. While they’re meant to inform us about the UV protection a sunscreen provides; the different regulations, labels, and how they’re tested can be become overwhelming. Learn to decode once and for all the mystery of sunscreen ratings.
  • What it stands for: Sun Protection Factor.
  • What it does for your skin: It only deals with the UVB part of the ultraviolet energy that comes from the sun. UVB energy causes redness and sunburn on the skin. Want a trick to remember this? Repeat with us: UVB, UV-Burn!
  • How it works: SPF is tested on a panel of 10-15 people (depending on the country) and it compares how much longer it takes for UVB to cause redness on the skin. So an SPF of 30 means that, if it took 10 minutes for redness to appear in unprotected skin, it’ll take around 30 times that for the same symptoms to appear on the skin if they’re wearing the SPF 30 properly.
  • What it stands for: Ultra Violet A.
  • More on UVA: SPF was developed at a time when we didn’t fully understand how damaging other forms of ultraviolet energy was to our skin. UVA makes up the majority of the UV energy that comes from the sun, and only until relatively recently did we realize how bad it was for our skin.
  • What it does to your skin: UVA energy doesn’t cause as much redness or sunburn, but it damages our skin’s genes, which leads to mutations and in the worst cases, cancer. For our beauty, it speeds up skin aging (hello, wrinkles, lines, and saggy skin) and can also cause hyperpigmentation. UVA radiation, which accounts for most of the sun’s rays, penetrates into the deeper levels of skin and is present all through the day, even on cloudy days.
    An easy way to remember? UVA, UV-Aging.
  • How to protect your skin against UVA: Nowadays, there’s better sunscreen filters that protect against UVA energy and there are tests that have been developed to create a “protection factor” for UVA. Unfortunately, it’s not globally standardized like SPF is, so there’s a few different methods that are used around the world—and get ready, here comes more acronyms…


  • What it stands for: Persistent Pigment Darkening.
  • How it works: Used in Asia and Europe, this system is similar to what you’ve learned here already about SPF. With the main difference that here we’re talking about UVA exposure and not UVB. PPD is tested on a panel of people exposed to UVA light. They all are analyzed on the time it takes for their skin to tan and compare the results between unprotected and protected skin. So a PPD of 10 means that it’ll take around 10 times longer for your skin to tan, compared to if it was unprotected.
spf meaning
Colipa UVA Method
  • What it stands for: A testing method for UVAPF that was standardized in Europe.
  • How it works: This method for testing UVA protection used in Europe isn’t done on people like PPD. Instead, it measures the amount of UVA energy that passes through a film of the sunscreen on a transparent piece of plastic, then a UVAPF (more on that below) is determined based on a model from these results.
  • What it stands for: Ultraviolet A Protection Factor.
  • How it works: It should be the same as SPF, but because of the different test methods for UVA protection, it isn’t always. PPD is the only standardized method, like SPF, where the rating is based on results on people.
  • What it stands for: Protection Grade of UVA.
  • How it works Used in Asian countries like Japan and South Korea, the PA system simplifies and groups the ratings from a PPD test. It ranges from PA+ to PA++++, being PA+ a sunscreen with a PPD of 2 to less than 4, PA++ one with PPD of 4 to 8, PA+++ from 8 to 16 and, finally, PA++++ those with a PPD of 16 or greater.
  • Disadvantages: Because of the way PA is set up, two sunscreens with a PPD of 20 and a PPD of 50 would both be rated as PA++++ or PA+++, and there’s no way to tell which one offers the higher protection.
  • More to know: Not all countries have updated the highest rating to PA++++ yet, still using PA+++ as their limit.
Broad Spectrum
  • What it stands for: Protection Grade of UVA.
  • How it works Used in the U.S. and Canada, this is, in our opinion, the easiest rating to pass—and doesn’t actually give us a good understanding of how well it will protect our skin from UVA damages. To achieve a broad spectrum rating, 90% of the total UV absorption must fall under 370 nm. We know, these numbers are hard to get, so let us tell you: This doesn’t necessarily translate to good UVA protection—the bar is set too low. 
    A sunscreen that protects against both UVA and UVB rays qualifies as broad spectrum, though there’s some criticism from consumer advocates over the fact that the testing required by the FDA to earn that ranking is pass/fail (meaning that if a sunscreen provides any measurable protection from UVA rays, it can call itself broad spectrum, even if that protection is very low.) Other countries, however, have different regulations on sun protectants, so many sunscreens from Europe and Asia show more specific rankings for UVA protection.
So, what level of UVA protection should you be looking for?
Ideally, the SPF and UVA protection factor should be close, if not the same (this mimics the effect that shade gives from the sun). In some specific cases, like if you’re concerned about hyperpigmentation or you pigment easily, you should probably look for a high UVA protection factor. And keep in mind: Applying enough sunscreen and reapplying is just as important (if not more!) than using a good product.

We hope this has helped you make sense of the confusing, and still developing, UVA rating systems that are used around the world. And check out three of our favorite sunscreens below!

+ What have you learned about SPF meaning? Share your knowledge below!

Research and collaboration: Stephen Ko

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