Sun Protection

UVA vs UVB: What's the Difference?

Sunlight reaches skin as a mix of wavelengths, and two — UVA and UVB — are the primary focus of sunscreen formulation. They behave differently, and broad-spectrum protection is designed to address both.

UVB: the burn ray

UVB rays are more associated with surface-level effects like sunburn and are the primary focus of the SPF rating. Their intensity varies more by season, time of day and geography.

UVA: the aging ray

UVA rays penetrate deeper into the skin, are more consistent throughout the day and year, and can pass through window glass. PA ratings (such as PA++++) are used in many regions to indicate a product's UVA protection level.

Why broad-spectrum matters

A sunscreen labeled broad-spectrum, or one showing both an SPF and a PA rating, is formulated to address both UVA and UVB — which is why DERMISCIA's Solerix formulations carry both an SPF and a PA rating rather than SPF alone.

FAQ

Both are relevant to skin health in different ways; dermatological guidance generally recommends protecting against both, which is what broad-spectrum, PA-rated sunscreens are designed to do.