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UVA et UVB : quelle est la différence ? Comprendre les indices de protection solaire pour protéger sa peau
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UVA and UVB: what is the difference?

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UVA, UVB… What is the difference between these ultraviolet rays? And what are the effects of UV light on our skin? To prevent the consequences of free radicals (wrinkles, brown spots, skin cancers, etc.), it is essential to protect your skin from UV radiation with a suitable sunscreen. Nooance-Paris helps you see things more clearly.

The difference between UVA and UVB

The sun emits electromagnetic waves or UV light that can be classified into different categories depending on their wavelength. In the class of ultraviolet rays, there are three subcategories:

  • UVC
  • UVB
  • And UVA rays , themselves classified into two subcategories: UVA2 called short UVA and UVA1 called long UVA ; some filters only protect against UVA2 and not UVA1.

UVC is filtered by the ozone layer. But this is not the case for UVA and UVB, which reach our skin and which can have several harmful consequences in the event of sun exposure.

The consequences of UVB

Of all the ultraviolet rays that reach us directly, only 5% are UVB rays. They are responsible for sunburn , which results from prolonged sunbathing. This is called oxidative stress: the formation of free radicals due to solar radiation leads to the appearance of sunburn and skin wrinkles.



UVB rays have the ability to penetrate the epidermis, that is to say in the first layer of the skin, where they play a filter role and activate the synthesis of melanin, the skin pigment, to protect us from UV light from the sun. Tanning is thus a defense mechanism of the skin against UV radiation.

The amount of UVB received depends on several factors:

  • Seasonality: there are more UVB rays in summer than in winter.
  • Time: there is more UVB when the sun is highest in the sky, between 11 a.m. and 4 p.m.
  • Other factors may come into play such as latitude, altitude, cloud cover or even reverberation.

The consequences of UVA

UVA represents 95% of UV rays that reach us and they can penetrate the skin more easily than UVB and reach the dermis, i.e. the second layer of the skin. UVA light can cause significant damage to our skin by directly altering compounds present like collagen and elastin fibers , which are two proteins responsible for skin firmness and elasticity.

UVA rays have the same level of intensity during daylight hours throughout the year, summer and winter. Additionally, they can also pass through windows and clouds.

So what are the differences between UVB and UVA?

Solar exposure to UVB rays thus leads to sunburn and the appearance of brown spots while UVA rays are more associated with premature aging of the skin . However, both types of UV are now found to play an important role in the development of skin cancer. This is why it is essential to avoid overexposure to the sun and to apply sun protection as soon as the UV index is greater than 2, or every day for anti-aging prevention purposes.



Understanding sun protection indices

SPF is the abbreviation of: Sun Protection Factor which means sun protection factor in French (SPF). We explain everything about their degree of protection.

An SPF15 product protects against 93% of UVB, that is to say it absorbs 93% of UVB, while the remaining 7% penetrates our epidermis. An SPF30 protects against nearly 97% of UVB and an SPF50 product protects against 98% of UV.

The European Commission has decided to group all indices above 50 into a single 50+ index . Indeed, an index higher than 60, for example an SPF index of 100, could be misleading and lead consumers to think that it would be twice as effective as SPF50, which is in reality not the case.

Regarding UVA protection, today it is not obligatory to mention it on the packaging. However, this must be equivalent to at least 1/3 of the SPF , that is to say that an SPF50+ product must have at least UVA protection of 20.

Sunglasses protect your eyes from the effects of UV radiation. But for your skin, only sunscreens can limit the effects of UV light, the appearance of brown spots and skin cancers.

How to effectively protect your skin from the sun?

There are many sunscreens with SPF50+ protection. Here we present to you the urban sunscreen developed by Nooānce to offer optimal protection of the skin against the effects of the sun.

Nooānce's Élégance UVA50 treatment has been designed to benefit from an anti-aging action, thanks to high protection against UVA 50, while protecting your skin from sunburn and UVB 30 thanks to use 4 organic sun filters. This sunscreen has a cream texture that is easy to apply and provides a mattifying finish, without white marks or sticky effect.

Thus, with its high UVA protection, this sun care is ideal for protecting the skin in summer and winter, or during bad weather. Even when UVB is less present and there is no risk of sunburn, it is important to protect your face from UVA to avoid premature aging of the skin.