There’s been quite a bit of media attention about sunscreen SPF ratings after a recent Choice report.  To help you understand what the SPF and UPF ratings mean, and how they are measured, we’ve produced this quick summary.  At Crazy Arms Clothing, we use and sell both sun protective clothing and sunscreens, and we’re not here to knock either.  Just help people understand the facts.

How are SPF and UPF ratings tested?

While both ratings sound similar, with ratings like 30+ or 50+, the way they work and the testing methodologies are quite different.

Sunscreen SPF is tested on human volunteers—a group of people apply the sunscreen and then their skin is exposed to a UV light to see how long it takes for it to redden. This approach accounts for individual skin differences, but it can be less consistent. 

Clothing UPF is tested using a lab-based, instrument-controlled method, which is very precise. A special device called a spectrophotometer measures the exact amount of UV radiation that passes through a fabric sample. This ensures a consistent and objective rating for every garment, regardless of who is wearing it.

Image source - ARPANSA video

How do sunscreen and clothing work to protect from UV rays?

Sunscreen’s SPF, or Sun Protection Factor, is a measure of how long it takes for your skin to burn when wearing the product, compared to when it's bare. So, a sunscreen with SPF 30 could theoretically let you stay in the sun 30 times longer before you get a sunburn. The key thing to remember is that sunscreen works by creating a chemical or mineral barrier on your skin, but this barrier isn't permanent. It needs to be reapplied every two hours, and more often if you’re swimming or sweating.  Not applying enough sunscreen, sunscreen getting washed off, or failure to reapply regularly are reasons why sunscreen can be a less reliable barrier.

Clothing, on the other hand, is a physical barrier that offers a more reliable and lasting form of protection. When a fabric is rated, it’s given a UPF, or Ultraviolet Protection Factor. This rating is determined in a laboratory.. A garment with a UPF 50+ rating, for example, allows less than 2% of UV rays to reach your skin. UPF-rated apparel is engineered to block both UVA and UVB rays, giving you comprehensive protection without the need for constant reapplication.  It's a consistent, dependable level of protection woven directly into the fabric itself.

Why clothing is king

This reliability of UPF50+ clothing is why, as a NSW Cancer Council executive remarked at a school sun safety session, "When it comes to sun protection, clothing is king."

While sunscreen is fantastic for all the skin that remains exposed, clothing provides a constant defence that you don't have to think about throughout the day. When you're planning your next day out, remember that while sunscreen is essential for some parts of the body, UPF clothing provides the ultimate, hassle-free sun safety.

Our blog articles are based on our own experience and research. For expert advice, please contact a medical professional.

Read more of our blogs

Will a pair of Sun Sleeves Save You Money - we've done the maths

Shop Crazy Arms UPF 50+ Sun Sleeves

Key article Sources: 

ARPANSA

Sydney Morning Herald

BBC