PA++++, Broad Spectrum, PPD: Sunscreen's UVA Ratings Decoded

SPF answers exactly one question: will you burn? It's a useful question, but burning isn't what quietly ages skin. The rays that break down collagen, blur your jawline, and deepen pigmentation over years are UVA — and SPF doesn't measure them at all. That's the gap every other label on a sunscreen is trying, confusingly, to fill.

The problem is that the world never agreed on a single way to rate UVA. So sunscreens carry a scattered alphabet — PA, PPD, "broad spectrum," a small UVA-in-a-circle logo — that all point at the same missing half of the protection. Decoding them is less complicated than it looks once you know they're answering one question in four regional dialects.

A dermatologist's five-word summary is the whole thing: "B is for burning, A is for aging." SPF covers the B. Everything below is how the label tells you about the A.

The two kinds of UV, briefly

UVB is the shorter, higher-energy wavelength that burns the surface — that's SPF territory. UVA is longer (roughly 320–400 nm), penetrates more deeply, and drives photoaging: wrinkles, loss of firmness, and pigmentation. It also contributes to skin-cancer risk independently of UVB. A sunscreen with a high SPF and no UVA credential is guarding the front door and leaving the back one open.

"Broad spectrum" (US, and the baseline everywhere)

In the US, "broad spectrum" is a pass/fail claim backed by a specific lab test. The sunscreen is exposed to UV across wavelengths, and the critical wavelength — the point below which 90% of its UV absorbance happens — must be at least 370 nm to earn the label. In plain terms: "broad spectrum" certifies the filter absorbs across a wide enough band to count as UVA-protective. It doesn't tell you how strong that UVA protection is — only that it cleared the bar.

The UVA circle (EU)

Europe (and Australia) require that 370 nm critical wavelength plus the UVA circle — the little "UVA" inside a ring. That logo carries a specific promise: the sunscreen's UVA protection is at least one-third of its SPF. So an SPF 30 with the UVA circle guarantees a UVA protection factor of at least 10. It's a floor, not an exact figure, but it ties UVA strength to the SPF you already see.

PA and PPD (Japan, Korea, much of Asia)

The Asian system is the most granular. PA ("Protection Grade of UVA") was developed in Japan and shows up as plus signs — PA+ to PA++++ — with more pluses meaning more UVA protection. It's built on a test called PPD (Persistent Pigment Darkening), which measures how much more UVA it takes to make skin tan through the sunscreen versus bare skin. Roughly:

The honest caveat: PPD scoring isn't precisely standardised, so a PA++++ tells you the protection is at least very high — you can't tell whether its true PPD is 16 or 40. And because the US FDA doesn't recognise the PPD method, US sunscreens rarely print a PA rating even when they'd earn one.

Putting it together

The practical read: a bare SPF number is half a sunscreen. Wherever your product comes from, look for the matching UVA signal — "broad spectrum" in the US, broad spectrum plus the UVA circle in the EU, or PA+++/PA++++ on Asian labels — alongside an SPF of 30 or more. The number and the letters are answering two different questions, and you want both answered.

In the Registry

• Vitamin C — a daytime antioxidant that mops up the free radicals UV generates; a complement to sunscreen, never a substitute
• How to use sunscreen — amount, timing, and reapplication
• Chemical vs mineral sunscreen — the filters doing the UVA/UVB work
• Sunscreen for deeper skin tones — finish and formulation beyond the ratings
• The anti-sunscreen claims, examined — separating real nuance from myth
• What does the SPF number actually mean? — the UVB half of the label, and why 50 is barely stronger than 30

Frequently asked questions

What's the difference between SPF and PA? SPF rates UVB (sunburn) protection; PA rates UVA (aging) protection. They measure two different types of ultraviolet radiation, which is why a good sunscreen needs both a solid SPF and a UVA indicator.

What does PA++++ mean? It's the highest UVA grade in the Asian PA system, corresponding to a Persistent Pigment Darkening (PPD) value of 16 or above. More plus signs mean more UVA protection; PA++++ has no upper cap.

What does "broad spectrum" actually guarantee? In the US, it's a pass/fail lab result: the sunscreen absorbs UV to a "critical wavelength" of at least 370 nm, certifying meaningful UVA coverage. It doesn't grade how strong that coverage is.

What is the UVA circle on European sunscreens? The UVA-in-a-circle logo means the product's UVA protection is at least one-third of its SPF. An SPF 30 with the circle has a UVA protection factor of at least 10.

Why don't US sunscreens show a PA rating? Because the US FDA doesn't recognise the PPD test that the PA system is based on. US products use "broad spectrum" to signal UVA protection instead.

Is a high SPF enough on its own? No. SPF only addresses UVB. Without a UVA credential — broad spectrum, a UVA circle, or a PA rating — a high-SPF product leaves you exposed to the rays most responsible for aging and part of skin-cancer risk.

This article is educational and explains how sun-protection labels are tested and defined; it isn't medical advice. For concerns about sun damage or skin-cancer risk, consult a dermatologist.

Related reading: Hyaluronic acid · how we grade.