What’s The Difference Between UVA And UVB?

When it comes to sun protection, we take no prisoners here at HintMD.

That being said, we know it can be confusing – it’s taken us years to get our heads around the ins and outs of the sun and its devillish, yet oh-so-desirable ways.

And we know one thing is still puzzling to the global community of both sun-worshippers and sun-avoiders – the different between UVA and UVB radiation and whether you should even care.

Well, it’s a big fat ‘yes’ to the latter, and for the former? Buckle down for a quick science lesson because its going to be a very informative ride. Albeit a very swift one – cue sighs of relief all round.

The Sun: Sunlight is split into various forms of radiation with UV (ultraviolet) being just a small portion of that electromagnetic spectrum. The reason we care so much about UV radiation is because, even though it’s invisible to the naked eye it damages the DNA of our skin cells. And we don’t like that.

UV Radiation: UV rays are split into three wavelengths – UVA, UVB and a third, much-less-talked-about UVC. We don’t really care so much about C, because although it contains more energy than the As and Bs of this world, UVC rays are so short, they don’t penetrate the Earth’s ozone layer. That’ll be one less to worry about, thanks ozone. 

UVA Rays: UVA rays have the longest wavelength and count for about 90 percent of the UV radiation reaching the Earth’s surface. Present all-year round, (not just on sunny days), these are the ones that can penetrate glass and go deeper into the skin’s surface, releasing free radicals and causing DNA changes. This means they’re the biggest culprits when it comes to premature aging and skin cancer. How to remember this one? Think ‘A’ for aging. 

UVB Rays: These bad boys are shorter in wavelength than UVA rays, so aren’t able to penetrate the skin as deeply. But don’t let that fool you as they are no innocent party. UVB plays a big part in tanning and is the primary cause of sunburn. Bad UVB. Its intensity varies throughout the year and, as you know, is most powerful in the middle of the day. How to remember this one? Think ‘B’ for burn.

So, what does all this mean for you? Good question. And the answer comes in the form of medical-grade sunscreen and asking your skincare expert to prescribe you one that protects you equally from both UVA and UVB. The SPF (sun protection factor) on your bottle of sun cream only protects your skin from UVB – annoying, right? – so, always choose a broad-spectrum formula (this means it protects against both) with an SPF of 15 or above. And look out for ingredients like zinc oxide, titanium dioxide, oxybenzone and Mexoryl which all offer UVA protection.

Lesson over. Now go safely enjoy the sunshine.

Written by: Georgia Gould