- UVA-PF, PPD, and PA all rate how well a sunscreen blocks UVA, the deeper rays behind aging and long-term damage, which SPF doesn't measure.
- UVA-PF and PPD give you a number; PA uses plus signs (PA+ to PA++++). UVA-PF is mostly European, PPD spans Europe and Asia, and PA is used in Asia.
- The U.S. only requires a 'broad-spectrum' label, which doesn't tell you how strong the UVA protection actually is.
- For stronger UVA coverage, look for a high UVA-PF, PA++++, or the UVA-in-a-circle symbol on E.U. packaging.
- One layer you don't have to decode: UPF 50+ clothing is broad-spectrum by default, blocking both UVA and UVB on the skin it covers, so only the exposed areas need sunscreen.
If you pay attention to skincare labels, you already know SPF only tells part of the story. It measures how well a sunscreen blocks UVB, the rays behind sunburn. But the deeper, quieter damage comes from UVA, the rays that drive premature aging and add to long-term risk, and that reach you every day of the year, even when it's cloudy or you're sitting by a window.
That's why so many people now look to European and Asian sunscreens, which often hold UVA protection to a higher standard and label it more clearly. If you've seen UVA-PF, PPD, or PA++++ and wondered what they mean, here's a straightforward guide so you can read any sunscreen label with confidence.
Why UVA Protection Matters for Your Skin
UVA makes up about 95% of the UV that reaches the Earth's surface, and it's around all day, every day, rain or shine. The two rays do different damage: where UVB burns the skin's surface, UVA reaches deeper into the skin and works quietly, so you won't feel it. Over time it can cause:
- Fine lines and wrinkles, by weakening the skin's structure
- Dark spots and uneven tone
- Long-term DNA damage that raises skin cancer risk
UVA also passes through windows and clouds, so you're exposed while driving, sitting near indoor light, or out on an overcast day, which is why UVA protection matters every day, not just on beach days.
What Is UVA-PF?
UVA-PF (Ultraviolet A Protection Factor) tells you how well a sunscreen blocks UVA. Unlike SPF, which measures only UVB, UVA-PF focuses on the deeper, aging rays. It isn't a test itself but a score, usually derived from the PPD test or ISO 24443, a lab method used in Europe.
In the E.U., a sunscreen's UVA-PF must be at least one-third of its labeled SPF to qualify as broad-spectrum. So an SPF 50 product needs a UVA-PF of at least 16.7. If you see the letters 'UVA' printed inside a circle on the packaging (the EU's UVA seal), the product meets this standard, and the higher the UVA-PF, the stronger the defense against sun damage.
How UVA-PF Is Measured
Two methods are used:
- In vivo (on real skin), the PPD test, which applies sunscreen to a test subject's skin and times how long the skin takes to start darkening from UVA, versus bare skin.
- In vitro (in the lab), where sunscreen goes on a textured plate that mimics skin (usually roughened PMMA, a clear plastic) and equipment measures how much UVA passes through. ISO 24443 is the common method here.
Both are considered reliable, and regions use one or the other depending on their standards.
UVA Star Rating (U.K.)
In the U.K., you may see the UVA Star Rating developed by Boots. It doesn't measure absolute UVA strength; it rates the ratio of UVA to UVB protection (in vitro) from 0 to 5 stars, where 5 stars means a very balanced ratio of 0.90 or higher.
| Star Rating | UVA/UVB Ratio | Interpretation |
|---|---|---|
| ★ | Below 0.40 | Very low UVA protection relative to UVB |
| ★★ | 0.40 – 0.59 | Low balance |
| ★★★ | 0.60 – 0.79 | Moderate UVA protection relative to UVB |
| ★★★★ | 0.80 – 0.89 | Good balance |
| ★★★★★ | 0.90 and above | Excellent balance |
A sunscreen can meet the E.U.'s UVA-PF rule and still earn fewer stars if the balance isn't as close, which is why the British Association of Dermatologists recommends 4 or 5 stars alongside SPF 30 or higher.
What Is PPD?
PPD (Persistent Pigment Darkening) is a test done on skin that measures how much longer protected skin takes to start tanning or darkening from UVA, compared to bare skin. It's one of the main ways UVA protection is measured, and it's also the basis for Asia's PA system.
PPD values generally fall into these bands:
- PPD 2–4: low UVA protection
- PPD 4–8: moderate
- PPD 8–16: high
- PPD 16+: very high
PPD isn't always printed on packaging, but when it is, it's a reliable indicator of UVA performance.
What Is the PA System?
PA (Protection Grade of UVA) was developed in Japan to make UVA ratings easy to read. Instead of a technical number, it uses one to four plus signs. Used mainly in Japan and South Korea, it's based on PPD results:
| PA Rating | PPD Value | UVA Protection Level |
|---|---|---|
| PA+ | PPD 2–4 | Low protection |
| PA++ | PPD 4–8 | Moderate protection |
| PA+++ | PPD 8–16 | High protection |
| PA++++ | PPD 16+ | Very high protection |
A PA++++ sunscreen gives Very High UVA protection, though it says nothing about UVB (SPF), so both values matter.
How Is UVA Protection Labeled in the U.S.?
In the U.S., the term broad-spectrum is regulated by the FDA, but it doesn't tell you how much UVA protection you're getting. Rather than requiring a UVA-PF or PPD score, U.S. sunscreens only have to pass the critical wavelength test, which checks that the sunscreen absorbs UVA out to at least 370 nanometers. In practice:
- A U.S. sunscreen can read 'broad-spectrum' even if it doesn't block much UVA.
- Brands don't have to list UVA-PF or PPD, so it's harder to know what you're actually getting.
The FDA has proposed stronger rules, including requiring UVA protection to be at least 70% as strong as the SPF (a UVA/UVB ratio of 0.7) for SPF 15 and up, but they haven't taken effect.
Photostability: Protection That Lasts in the Sun
Photostability is how well a sunscreen holds up after sun exposure. Some filters, like avobenzone, break down in sunlight, so the product loses UVA protection even while the SPF number still looks fine. To get protection that lasts, look for sunscreens that:
- Say they're photostable or offer long-lasting UVA protection
- Lean on stable filters; in the U.S., zinc oxide is the steadiest broadly available one, while avobenzone gives UVA coverage but breaks down in the sun
The bigger news: in June 2026 the FDA approved bemotrizinol (sold abroad as Tinosorb S or Parsol Shield), the first new UV filter in over 25 years and a strong, stable, non-mineral UVA blocker used in Europe and Asia since 1999. It directly closes the long-standing U.S. UVA gap, though products are still reaching shelves. Other effective filters, like Mexoryl and Tinosorb M, still aren't broadly approved here.
How These UVA Ratings Compare
| System | Region | What it measures | How it's determined |
|---|---|---|---|
| UVA-PF | Europe | Level of UVA protection | Derived via PPD or ISO 24443 |
| UVA Star Rating | U.K. | UVA/UVB balance (not absolute UVA-PF) | In vitro UVA-to-UVB absorbance ratio |
| PPD | Europe, Asia | UVA protection on real skin | Human skin pigmentation testing |
| PA System | Asia | Consumer-facing label | Based on PPD value |
| Broad-Spectrum | U.S. | Absorption across the UVA/UVB range | Critical wavelength test ≥370 nm |
How to Choose a Sunscreen with Strong UVA Protection
If you want a sunscreen that guards against wrinkles and dark spots, not just sunburn:
- In Europe, look for the UVA-in-a-circle symbol (UVA protection at least one-third of the SPF).
- In the U.K., check the UVA star rating and aim for 4 or 5 stars.
- In Asia, look for PA++++; more plus signs means stronger UVA protection.
- In the U.S., since UVA isn't always shown, choose brands that share test results, lean on zinc oxide, or look for the newly approved bemotrizinol (Tinosorb S).
- Anywhere, make sure it's photostable, so it holds up instead of breaking down in the sun.
Frequently Asked Questions About UVA Protection
Here are answers to some of the most common questions about UVA protection.
What does UVA-PF mean?
UVA-PF (Ultraviolet A Protection Factor) measures how well a sunscreen blocks UVA, the rays behind premature aging, dark spots, and long-term damage. Unlike SPF, which measures only UVB, UVA-PF focuses on the deeper rays that cause cumulative damage.
What's the difference between PA+ and PA++++?
The PA system rates UVA protection with plus signs based on PPD results: PA+ is low (PPD 2–4), PA++ moderate (PPD 4–8), PA+++ high (PPD 8–16), and PA++++ Very High (PPD 16+). More plus signs means longer protection against UVA damage.
How does PPD differ from SPF?
They measure different rays. SPF rates protection from UVB (the burning rays). PPD rates protection from UVA (the deeper, aging rays). A sunscreen can have a high SPF and still offer weak UVA protection, which is why both numbers matter.
What is photostability in sunscreen?
It's how well a sunscreen holds up in sunlight. Some filters, like avobenzone, break down over time, lowering UVA protection even when the SPF still looks strong. Steadier filters hold up better: zinc oxide, or bemotrizinol (Tinosorb S), which the FDA approved in June 2026 as the first new UV filter in over 25 years. A few effective options, like Mexoryl, still aren't broadly approved in the U.S.
Why does UVA protection matter year-round?
UVA is about 95% of the UV that reaches you, present every day regardless of weather or season. It passes through clouds and windows, so your skin is exposed even indoors or on a cloudy drive. Because the damage accumulates, daily UVA protection matters as much as protection during peak sun.
The Essential Takeaway: UVA Protection Matters for Healthy Skin
SPF is only part of the story. UVA drives premature aging and cumulative damage, and it reaches you even indoors or on cloudy days, so it deserves attention every day. Understanding UVA-PF, PPD, and PA helps you read a label and choose well.
The simplest way to need less of this decoding is to let your clothing carry more of the load. UPF 50+ clothing is broad-spectrum by default, blocking both UVA and UVB on the skin it covers, so that skin is protected no matter which rating system you're standing in, leaving just your exposed areas for sunscreen. The best sun protection is the kind you can live in.
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