Q&A Series #70

A: The PA grading system was established in Japan, and is meant to inform users of the level of protection from #UVA rays.

The PA rating system was adapted from the Persistent Pigment Darkening (PPD) method. This test uses UVA radiation to cause a persistent darkening—tanning—of the skin. PPD is tested on a variety of people, all exposed to UVA light. Every test subject is analyzed on how long it takes for their skin to tan. Researchers then compare the results between unprotected and protected skin.

In theory, a sunscreen with a PPD rating of 10 should allow an individual to handle 10 times as much UVA exposure. However, PPD values can’t be measured precisely; because there’s no standardized system for evaluating PPD score, various rating systems are used to signal a product’s UVA protection strength.

PPD doesn’t indicate the exact amount of UVA protection a product provides; instead, this test is converted into a country or region’s scoring system.

Currently, only five countries utilize UVA testing: Japan, the United Kingdom, Germany, the United States, and Australia. In Japan, PPD results are grouped and simplified into PA measurements.

These conversions go as follow:

If a product’s PPD = 2 to 4, PA = PA+

If a product’s PPD = 4 to 8, PA = PA++

If a product’s PPD = 8 to 16, PA = PA+++

If a product’s PPD = 16 or higher, PA = PA++++

PA+ means your sunscreen or cosmetic provides some protection against UVA rays, PA++ provides moderate protection, and PA+++ offers the best protection of the three. Recent advancements have seen the introduction of PA++++ products in certain countries; this grade offers PPD protection of 16 or more. However, the latter rating is rare, as this level of protection is found in few products.

In recent years, Japan was the first country to increase its PA ratings to include PA++++, but not all countries have updated, and still use PA+++ as their limit. According to The Klog, because of the way PA sunscreens are categorized, it can be difficult to determine the difference in sun protection; for example, a sunscreen with a PPD of 20 and a sunscreen with a PPD of 40 could both be rated as PA+++ or PA++++, but there’s no way to tell which one offers superior protection.

Here’s an easy guide when shopping for sunscreens and cosmetics that utilize the PA+++ rating: , .

Article taken from Colorescience’s Blog.