Glossary

PA Rating

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PA Rating — a labeling system, common in Asian sunscreens, that indicates the level of UVA protection using plus signs from PA+ to PA++++. It is based on the persistent pigment darkening method and complements SPF, which mainly reflects UVB protection.

Key points

  • The PA rating measures UVA protection and is derived from the PPD (persistent pigment darkening) test method.
  • More plus signs indicate greater UVA protection, ranging from PA+ for some protection up to PA++++ for the highest level.
  • The PA system is widely used in Japan, Korea, and other markets, while other regions may use different UVA labeling such as a circled UVA seal.
  • PA rating works alongside SPF, together signaling protection across both UVA and UVB wavelengths.

Frequently asked

What does PA++++ mean?

It indicates the highest level of UVA protection on the PA scale, based on the persistent pigment darkening test, and pairs with SPF to convey overall coverage.

How is PA rating different from SPF?

SPF mainly measures protection against UVB rays that cause sunburn, while the PA rating specifically communicates the level of UVA protection.

Related topics

This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.

Encyclopedia

Further reading

This entry was written and checked against the sources below. They are published by clinical and scientific bodies, they are listed most readable first, and each one opens in a new tab. They are background for the whole entry rather than footnotes to individual sentences.

  1. Sunscreens and Photoprotection StatPearls (NCBI Bookshelf) Reference text ncbi.nlm.nih.gov
  2. Labeling and Effectiveness Testing: Sunscreen Drug Products for Over-The-Counter Human Use — Small Entity Compliance Guide U.S. FDA Regulatory and safety fda.gov
  3. Questions and Answers: FDA announces new requirements for over-the-counter (OTC) sunscreen products marketed in the U.S. U.S. FDA Regulatory and safety fda.gov
  4. Ultraviolet Filters: Dissecting Current Facts and Myths PubMed Central Peer-reviewed, open access pmc.ncbi.nlm.nih.gov
  5. In vitro assessment of the broad-spectrum ultraviolet protection of sunscreen products PubMed Peer-reviewed (abstract) pubmed.ncbi.nlm.nih.gov
  6. Overview of proficiency testing results for the in vivo determination of sun protection factor PubMed Peer-reviewed (abstract) pubmed.ncbi.nlm.nih.gov

SYNC does not publish medical advice. Nothing here replaces a consultation with a doctor or a pharmacist about your own skin.