When it comes to sun protection, most people focus on sunscreen with SPF—but SPF only measures protection against UVB rays, which cause sunburn. However, up to 90% of visible skin aging—like wrinkles, fine lines, and dark spots—is caused by UVA exposure. These rays penetrate deeper into the skin, leading to premature aging, hyperpigmentation, and an increased risk of skin cancer. That’s why understanding UVA protection ratings is just as important as checking SPF when choosing a sunscreen.
If you’ve ever come across terms like UVA-PF, PPD, and the PA system, you might wonder what they mean and how they relate to each other. In this guide, we’ll review these UVA protection terms, explain how they differ, and help you make more informed decisions about shielding your skin from long-term damage.
Why UVA Protection Matters
UVA rays make up about 95% of the UV radiation that reaches the Earth’s surface, meaning you’re exposed to them all year round, even on cloudy days. The remaining 5% consists of UVB rays, which are responsible for sunburn. Unlike UVB rays, which cause immediate sunburn, UVA rays penetrate deeper into the skin, leading to:
- Wrinkles and fine lines (by breaking down collagen and elastin)
- Hyperpigmentation and dark spots
- Increased skin cancer risk, as they cause DNA damage over time
While SPF ratings measure UVB protection, they don’t indicate how well a sunscreen protects against UVA rays—which is where UVA-PF, PPD, and the PA system come in.
What Is UVA-PF?
Ultraviolet A Protection Factor (UVA-PF) is the European standard for UVA protection.
UVA-PF measures how effectively a sunscreen blocks UVA radiation, which is responsible for skin aging and long-term damage. In Europe, a sunscreen must have a UVA-PF of at least one-third of its SPF to be labeled broad-spectrum, ensuring balanced protection against both UVA and UVB rays. A higher UVA-PF indicates stronger defense against UVA-induced photoaging and skin cancer risks, making it an important factor in choosing an effective sunscreen.
For example:
- SPF 50 sunscreen in Europe must have at least a UVA-PF of 16-20 to be broad-spectrum.
- This ensures a balance between UVB and UVA protection.
The UVA-PF rating is often determined using PPD testing, which leads us to the next key term.
What Is PPD?
Persistent Pigment Darkening (PPD) is a test used to measure UVA protection in sunscreens.
PPD measures how much longer skin can tolerate UVA exposure compared to unprotected skin. Its values correlate directly with UVA-PF, meaning a higher PPD indicates stronger UVA defense. For example, a PPD of 10 means your skin can endure 10 times more UVA exposure than without sunscreen.
PPD Scale:
- PPD 2-4: Low UVA protection
- PPD 4-8: Moderate UVA protection
- PPD 8-16: High UVA protection
- PPD 16+: Very high UVA protection
Where Is PPD Used?
- Europe: PPD testing ensures UVA-PF is at least 1/3 of SPF (or a ratio of 1:3), a requirement for broad-spectrum labeling.
- Asia: The PA system (PA+, PA++, PA+++, PA++++) is based on PPD values, providing a consumer-friendly way to gauge UVA protection.
- Other Regions: Some brands voluntarily disclose PPD values, even when not required, to provide transparency on UVA defense.
Since PPD is a test method rather than a consumer-facing label, it’s primarily referenced in regulatory standards and sunscreen formulation rather than on packaging.
What Is the PA System?
The PA system (Protection Grade of UVA) is an Asian UVA protection rating system based on PPD values.
Since PPD values are not always consumer-friendly, the PA system was developed based on the PPD test to simplify UVA protection ratings. It has since been widely adopted across Asia, including Japan, China, and South Korea, providing an easier way for consumers to understand UVA protection levels in sunscreens.
The PA scale converts PPD values into four easy-to-read categories:
| PA Rating | PPD Value | UVA Protection Level |
|---|---|---|
| PA+ | PPD 2-4 | Low UVA protection |
| PA++ | PPD 4-8 | Moderate UVA protection |
| PA+++ | PPD 8-16 | High UVA protection |
| PA++++ | PPD 16+ | Very high UVA protection |
For example, a sunscreen labeled PA++++ has a PPD of 16 or higher, meaning it offers strong UVA protection.
Does the PA System Guarantee UVB Protection?
No—a high PA rating does not automatically mean a sunscreen is broad-spectrum. A sunscreen could have PA++++ but a low SPF, meaning it still leaves skin vulnerable to sunburn. Always check for both high SPF and PA++++ for full broad-spectrum UV protection.
How Do These UVA Ratings Compare?
| UVA Protection System | Region Used | How It Works | How It Relates to Others |
|---|---|---|---|
| UVA-PF | Europe | Measures UVA protection (must be 1/3 of SPF, a ratio of 1:3) | Derived from PPD test |
| PPD | Global (mainly Europe, Asia) | Test method that calculates UVA protection based on tanning response | Used to determine UVA-PF and PA rating |
| PA System | Asia (Japan, Korea, China) | Consumer-friendly UVA rating based on PPD | PA++++ = PPD 16+ |
Key Takeaways:
- European sunscreens must meet a minimum UVA-PF to be labeled broad-spectrum, ensuring a strong balance of UVA and UVB protection.
- PPD testing is the foundation for both UVA-PF and PA ratings—a higher PPD means better UVA defense.
- Asian sunscreens often highlight PA ratings, but they don’t necessarily guarantee broad-spectrum UVB protection.
For the best sun protection, choose a broad-spectrum sunscreen with high SPF and UVA-PF, PA++++, or disclosed PPD values.
How Understanding These Ratings Helps You Choose the Best Sunscreen
UVA protection is just as important as SPF when selecting a sunscreen. While SPF measures UVB protection, it doesn’t indicate how well a sunscreen shields against UVA rays, which contribute to skin aging and long-term damage.
To ensure balanced protection, check for:
- Broad-Spectrum Labeling: In the U.S., broad-spectrum sunscreen currently only requires some UVA protection, but in Europe, it must meet a standard where UVA-PF is at least 1/3 of SPF (or a ratio of 1:3). In Asia, PA ratings (PA++++ is best) indicate stronger UVA defense.
- UVA Protection Matching SPF: A well-balanced sunscreen should have a UVA-PF or PPD value of at least 1/3 of its SPF (a ratio of 1:3). If not listed, look for European regulations or PA++++ for better UVA defense.
- Regional UVA Standards: European sunscreens follow strict UVA-PF requirements, while Asian sunscreens indicate UVA protection with PA ratings. U.S. sunscreens can be labeled broad-spectrum without a set UVA-PF minimum, so additional UVA details are important.
By understanding these ratings, you can choose a sunscreen that provides both UVB and UVA protection. For full coverage, pair broad-spectrum sunscreen with UPF clothing to shield exposed areas, reducing the need for frequent sunscreen reapplication.
The Bottom Line: Understanding UVA Ratings = Better Sun Protection
While SPF is essential for blocking sunburn-causing UVB rays, UVA protection is just as important for preventing long-term skin damage and premature aging.
- UVA-PF (Europe) ensures a minimum UVA protection level relative to SPF.
- PPD testing measures how much UVA radiation a sunscreen blocks.
- The PA system (Asia) simplifies UVA ratings for consumers.
By understanding these UVA protection terms, you can make more informed choices when selecting sunscreen—whether you want stronger anti-aging benefits, protection against hyperpigmentation, or defense against long-term UV damage.
For consistent protection, pair broad-spectrum sunscreen with UPF 50+ clothing, ensuring your skin stays shielded from both UVB burns and deep UVA damage.
Live well under the sun!
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