PureSPF provides evidence-based sunscreen guides, UV protection tools, ingredient analysis, and practical skin-protection advice.
Powerful tools to help you make smarter sun protection choices.
Calculate how often you should reapply sunscreen based on your skin type, UV index and activity level.
Open Calculator →Check the current UV index anywhere in the world and get personalized protection recommendations.
Check UV Index →Paste any sunscreen ingredient list and analyze safety, benefits, and potential irritants.
Analyze Ingredients →Compare mineral and chemical sunscreens in detail to find what's best for your skin and lifestyle.
Compare Guide →Test your knowledge and discover the truth behind common sunscreen myths.
Explore Myths →Stay informed with our latest sunscreen guides and skin health tips.
All content is backed by peer-reviewed photobiology research and published scientific evidence.
Independently verified against peer-reviewed journals, published formulation studies, and photoprotection standards.
We accept no direct brand sponsorships, guaranteeing unbiased product and ingredient safety evaluations.
We continuously update our UV Index databases and ingredient safety rating metrics.
Understanding photoprotection requires a clear grasp of how solar ultraviolet radiation interacts with human skin. Ultraviolet Light is categorized into two key biological spectrums: UVB (290–320 nm) and UVA (320–400 nm). While UVB radiation directly damages epidermal DNA structures causing erythema (sunburns), UVA radiation penetrates deep into the dermal matrix, generating reactive oxygen species (ROS), accelerating photoaging, and breaking down structural collagen and elastin fibers.
The Sun Protection Factor (SPF) measures how much solar radiation is required to produce sunburn on protected skin relative to unprotected skin. Contrary to popular belief, SPF does not scale linearly:
A sunscreen labelled "Broad Spectrum" passes critical wavelength testing indicating it protects against both UVA and UVB rays. In Asian markets, the PA Rating System specifically grades UVA protection based on Persistent Pigment Darkening (PPD):
