BIODERMA photo, Kid with sun care, sun screen, outdoor, beach
Summer with Bioderma

Sun protection: UVA / UVB untangle fact from fiction

It’s already late July, and the sun is out to play! Whether it be online or in stores, we are constantly provided with recommendations for finding the perfect sunscreen: texture, composition, formula. How can we choose the best option? Do we even know what high quality protective sunscreen is? Not sure what UV radiation is? Don’t worry, Bioderma is here to shed some light on the world of sun protection.

Different types of ultraviolet rays

Let’s start at the center of our solar system. UV stands for “ultraviolet.” Ultraviolet rays are emitted by the sun and they make their way to our planet.

The sun radiates 3 different types of UV rays: UVA, UVB, and UVC: which are characterized by different wavelengths. Usually, when dealing with UV rays, we are only talking about the first two as the third type of UV rays, UVC, can’t pass through the earth’s ozone layer and reach its surface!

On the World Health Organization website, it states that UV rays can possess different qualities, penetrating the skin differently.

We already know that UVC. can’t reach earth’s surface. When choosing a sunscreen, we must pay attention to both the UVA and UVB protection index. Often, a common mistake is thinking that we only have to look at the UVB index. However, it is essential to understand UVA rays, too, as they can still penetrate the skin and damage it!



UVA radiation: A is for Allergy

UVA rays can be found all year long, no matter the weather! They make up about 95% of the total UV rays here on earth.

With relatively long wavelengths, 320 to 400 nm, UVA rays are intense and can penetrate through clouds, glass, and skin. However, unlike UVB rays, UVA rays show no visible trace on the skin; no redness, no burns … Even though they are often not visible on the skin, they are far from being harmless! In reality, they can actually penetrate the skin beyond the epidermis and can lead to damage.

UVA rays can, in some cases, cause:

– Skin aging

– Sun intolerance (or sun allergies)

– Hyperpigmentation

– The development of skin cancer


 UVB radiations: B for Burn

UVB radiation, on the other hand, has an average wavelength between 280 and 320 nm. According to WHO, and unlike UVA, they can’t penetrate more than the outermost layer of our skin.

UVB rays can be responsible for:

– delayed tanning

– sunburns

– skin aging

– the development of skin cancer


How to be sure you’re making the right choice?

Be sure to look at the SPF, A.K.A. sun protection factor. SPF is always followed by a number: 15, 25, 30, 50, etc. This number is the ratio of time required for U.V. rays to create a sunburn without sun protection. According to the Health Canada website, SPF is a relative measure of the time it would take for unprotected skin to burn in the sun compared to the time it would take for it to burn after applying the recommended amount of sunscreen.


The SPF is also used as a reference to understand the UVB intensity that is blocked by sun protection. For example:

– SPF 15: can block up to 93% of UVB radiation

– SPF 30:: can block up to 96.7% of UVB radiation

Another clue is to see if the “UVA” is circled on the front of the product: this means that the UVA protection is equal to at least 1/3 of the UVB protection (SPF).

Overall, you must be sure to protect your skin from U.V. rays all year round, no matter the weather, as 80% of the sun’s rays can still make their way through clouds, haze, and fog onto our skin and create lasting problems!


With these tips in mind and your skin protected, you are now ready to play with the sun!

BIODERMA photo, Kid with sun care, sun screen, outdoor, beach
Summer with Bioderma

It's already late July, and the sun is out to play! Whether it be online or in stores, we are…

Read more

Receive our latest news!