What’s the difference between UVA and UVB rays?

by Gio
difference between uva and UVB rays

Can you believe that for decades sunscreen protected only from UVB rays?

No one gave a crap about UVA rays. They don’t cause sunburns, so who cares if they give you wrinkles (and that’s not even the worst thing they do…)?

I do. Cos UVA rays are even worse than UVB rays. Yep, not all UV rays are created equal. UVA and UVB rays do different things to your skin and you want to be protected from both.

Here’s the difference between UVA and UVB rays (and why your sunscreen should cover both):

What are UVA rays?

UVA rays represent about 95% of the UV radiation that reaches the earth! These long wave UV rays are present every single day, from the moment the sun comes up to the moment it goes away. 

They easily penetrate the darkest of clouds and shiny windows and even get reflected on snow. It doesn’t matter if you’re in the middle of the desert, in a chaotic city or on top of a snow-covered mountain. Those pesky UVA rays will get you EVERYWHERE (including your own home, if you sit near the windows) until the sun sets!

That’s why they are way more damaging than UVB rays – even though they’re weaker! The damage UVA rays do to your skin is continuous and severe, but it doesn’t show up straight away.

With UVA rays, there’s no tell-tale warning. You know, that darkening of the skin that tells you, “get out of the sun, now!” (yep, a tan is your body’s way of telling you you’ve overstayed your welcome in the sun).

UVA rays generate an endless stream of free radicals, the nasty buggers that give you wrinkles. They also reduce elastin, the protein that keeps your skin elastic and bouncy (that’s why tanners get deeper wrinkles, by the way).

UVA rays don’t just make you age faster. They also cause abnormal cell production. Translation: they can lead to cancer. Don’t risk it!

UVA is for aging and UVB is for burning. Make sure your sunscreen protects you from both!Click to Tweet

What are UVB rays?

UVB rays emit medium wave ultraviolet radiation, so only about 5% reaches our planet. The rest is absorbed by the clouds and ozone layer (which we humans are stupidly destroying).

UVB rays are stronger between 10 a.m and 4 p.m. (that’s why your mom told you to stay out of the sun during those hours) but can’t pass through clouds or windows. If you’re inside, you’re safe. Phew!

They’re not as numerous as UVA rays, but they’re more powerful so they can still do a lot of damage. Some of this damage is visible as it happens. I’m talking about sunburns. As soon as you see your face turning red, you know UVB rays have got you.

That’s not all they do. Like UVA rays, UVB rays can cause abnormal cell mutation and give you cancer. Five serious sunburns are enough to increase your risk of skin cancer by 80%! Stay safe!

The Bottom Line

These days, (almost) all sunscreens give you both UVA and UVB coverage. But, it’s still possible to find a dud that slacks on UVA protection. Make sure to leave it on the shelf!

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Trisha June 29, 2010 - 9:30 pm

You’re so smart. 😉

beautifulwithbrains June 30, 2010 - 6:41 am

You’re too kind, Trisha, thanks.

Nikki June 30, 2010 - 12:48 am

Thanks for sharing this information, I remember going on a seminar about UVB and UVA and its really informative to know! thanks for the reminder!

beautifulwithbrains June 30, 2010 - 6:42 am

Nikki, you’re welcome. That seminar must have been very interesting. 🙂

Tammy June 30, 2010 - 12:53 am

Very informative! I use a zinc oxide and titanium oxide based sunscreen because they are the most stable and long lasting (on me, at least). It feels heavier, but it works better for me. What do you use?

beautifulwithbrains June 30, 2010 - 6:49 am

Tammy, I prefer to use sunscreens that contain Zinc Oxide and Titanium Dioxide as these ingredient offer protection from both UVA and UVB rays and are less likely to cause negative reactions than chemical filters. I may sometimes switch and try something with Mexoryl if it’s a product that particularly interests me but usually I stick with Zinc Oxide and Titanium Dioxide. Sure, they may feel a bit heavier and sometimes leave a white cast, but I think that’s a very small price to pay for the good protection they offer. 🙂

Celina Lee June 30, 2010 - 2:12 am

This is a great post, it clearly lays everything out, no confusion at all 🙂

beautifulwithbrains June 30, 2010 - 7:05 am

Celina Lee, thanks. I’m glad you find this helpful. 🙂

Dee June 30, 2010 - 2:25 am

Thanks for this Gio. I had no idea there were UVC rays.

beautifulwithbrains June 30, 2010 - 7:06 am

Dee, you’re welcome. I only recently found out about UVC rays too but I’m glad we don’t have to worry about them as they never reach the earth. 🙂

Dao June 30, 2010 - 3:14 am

I have this trick: A is for aging, B is for burn 🙂 That’s how I differentiate UVA and UVB. This year, the weather is so brutal that I need a back up for my sunscreen. It is a mineral finishing powder from EDM that has both zinc oxide and titanium dioxide. I love it!

beautifulwithbrains June 30, 2010 - 1:11 pm

Dao, that’s a great and simple way to remember the difference between UVA and UVB rays. 🙂 That sounds like a good powder. The weather is very hot here too so it’s nice to retouch makeup with a finishing powder with SPF for some added protection. 🙂

louise October 2, 2012 - 3:00 pm

Hi there – my website will be live in a weeks time..
I am setting up a skincare business and will be raising skin cancer awareness too. The UVA UVA diagram you have is brilliant. Could I please ask your permission to use this?
I look forward to hearing from you.
Best Regards,

beautifulwithbrains October 2, 2012 - 8:43 pm

Louise, hi. I think it’s great that you wanna raise skin cancer awereness and I wish you all the best with your skincare business.

The diagram isn’t mine, but it’s from the Make Me Heal website, so you should ask them. You can find the link to the site at the end of the post.


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