PA stands for Protection Grade of UVA. It’s a rating system, developed by the Japanese Cosmetic Industry Association, that tells you how well a sunscreen shields your skin from UVA rays. You’ll see it written as PA followed by plus signs, from PA+ (some protection) up to PA++++ (extremely high protection). While SPF measures protection against the rays that cause sunburn, PA measures protection against the deeper-penetrating rays that cause premature aging and contribute to skin cancer.
What the Plus Signs Mean
The PA rating is based on a lab measurement called PPD, or Persistent Pigment Darkening. In simple terms, testers apply sunscreen to a patch of skin, expose it to UVA light, and measure how much longer it takes for the protected skin to darken compared to unprotected skin. A PPD of 8, for example, means the sunscreen lets you withstand eight times more UVA exposure before your skin visibly darkens.
Those PPD numbers get translated into a plus-sign scale:
- PA+ = PPD of 2 to 4 (some UVA protection)
- PA++ = PPD of 4 to 8 (moderate UVA protection)
- PA+++ = PPD of 8 to 16 (high UVA protection)
- PA++++ = PPD of 16 or higher (extremely high UVA protection)
PA++++ is the highest rating the system allows. A sunscreen at this level blocks a significant amount of UVA radiation, though no sunscreen blocks 100% of UV light.
Why UVA Protection Matters
UVA rays account for roughly 95 percent of the ultraviolet radiation that reaches the earth’s surface, and they maintain the same intensity throughout daylight hours, year-round. Unlike UVB rays, which peak midday and cause obvious sunburn, UVA exposure is constant and largely invisible in its immediate effects.
That doesn’t mean UVA is harmless. These longer wavelengths (320 to 400 nanometers) penetrate deeper into your skin than UVB rays do, reaching the innermost part of the top skin layer where most skin cancers develop. Over time, this deeper penetration damages collagen and elastin, leading to wrinkles, sagging, and dark spots. UVA radiation is a proven contributor to skin cancer development. Because you can’t feel UVA damage happening the way you feel a sunburn, it’s easy to accumulate years of exposure without realizing it.
How PA Differs From SPF
SPF and PA measure protection against two different types of ultraviolet light. SPF, or Sun Protection Factor, tells you how well a sunscreen blocks UVB rays, the shorter wavelengths (280 to 320 nanometers) responsible for sunburn. PA tells you how well it blocks UVA rays. A sunscreen with SPF 50 but only PA+ offers strong burn protection with minimal aging protection.
For well-rounded sun protection, you want both numbers to be high. A good rule of thumb: look for at least PA+++ alongside your preferred SPF level. PA++++ is ideal for extended outdoor time or if preventing photoaging is a priority.
PA vs. “Broad Spectrum” Labels
If you buy sunscreen in the United States, you won’t typically see a PA rating. Instead, the FDA uses a “Broad Spectrum” label, which means the product provides UVA protection proportional to its UVB protection. The catch is that “Broad Spectrum” is a pass/fail designation. It tells you UVA protection exists but doesn’t tell you how much.
European sunscreens take a middle approach. Products carrying the UVA logo inside a circle must have a PPD value of at least one-third of their SPF. So a European SPF 50 sunscreen with the UVA circle has a PPD of at least about 17, which is equivalent to PA++++. This makes European labeling more informative than the U.S. system, though still less granular than the four-tier PA scale common in Japanese and Korean products.
The PA system gives you the most specific information at a glance, which is one reason it’s popular among people who pay close attention to sun protection.
UVA Filters Can Break Down Faster
One practical detail worth knowing: some UVA-blocking ingredients lose their effectiveness faster than UVB filters when exposed to sunlight. Research on common UVA-absorbing compounds has shown rapid decreases in UVA absorption after UV exposure, while UVB filters held up better under the same conditions. This means your PA protection may degrade more quickly than your SPF protection over a day in the sun.
Reapplying every two hours, or sooner after swimming or sweating, helps maintain both UVA and UVA coverage. This is especially important if you’re relying on your sunscreen’s PA rating for anti-aging benefits during prolonged outdoor activity. Newer sunscreen formulations often include stabilizing ingredients that help UVA filters last longer, but regular reapplication remains the most reliable strategy.
Choosing the Right PA Rating
For daily commuting and incidental sun exposure, PA+++ is generally sufficient. If you spend extended time outdoors, live in a high-UV-index area, or are specifically concerned about photoaging and hyperpigmentation, PA++++ is worth seeking out. Many Japanese and Korean sunscreens prominently display their PA rating on the front label, making comparison straightforward.
When shopping for sunscreen from U.S. or European brands that don’t use the PA system, look for the term “Broad Spectrum” at minimum. European products with the UVA circle logo offer a stronger guarantee of meaningful UVA protection. If a product lists its PPD value (some do, especially in enthusiast-oriented brands), you can convert it yourself: a PPD of 16 or above equals PA++++.