What is the difference between UVA and UVB?
When should you start protecting your skin from the sun?
Even when temperatures remain cool in spring, ultraviolet radiation can already be strong enough to affect the skin. Understanding the role of UV rays and learning to gradually expose the skin to the sun helps preserve skin balance.
Dermatologists generally recommend applying sunscreen when the UV index reaches 3, especially if sun exposure exceeds 15 to 20 minutes in full sun. This level of intensity is often reached in spring, even when temperatures remain cool.
It’s 18°C. The light feels soft. And yet, your skin is already being exposed.
The skin, it is already working.
After several months of winter, she has been little exposed to the sun. When the first rays appear, the sensation is pleasant, almost trivial. Yet, even when the warmth remains light, the ultraviolet rays are already affecting the skin.
The tan that we look forward to with the arrival of sunny days is actually a defensive response. In the face of UV rays, the skin produces melanin in an attempt to limit the damage caused by solar radiation.
The skin has its own protective mechanisms.
Our role is mainly to preserve them.
What are the different types of UV: UVA, UVB, and UVC?
We often talk about the sun as a unique phenomenon. In reality, several types of ultraviolet radiation reach the skin and act differently.
UVB rays primarily act at the level of the epidermis. They are responsible for sunburn and stimulate the production of melanin, which leads to the gradual tanning of the skin.
The UVA rays are present more consistently throughout the year. They penetrate deeper into the skin and gradually alter its supportive fibres (collagen and elastin). Their effect is less immediately visible, but they actively contribute to skin ageing. They can also contribute to tanning by oxidising the melanin already present in the skin, which results in a more immediate but temporary tan.
The UVC rays are the most energetic. Fortunately, they are almost entirely filtered by the ozone layer and do not reach the Earth's surface under natural conditions.
Even when the sun seems gentle, the skin can already be exposed to radiation capable of causing invisible skin damage.
At what UV index should you apply sunscreen?
The sensation of heat is not a good indicator of the intensity of the sun. It is the UV index that measures the actual strength of ultraviolet radiation.
UV index 1 to 2: low intensity
UV index 3 to 5: moderate intensity
UV index 6 to 7: high intensity
UV index 8 and above: very high intensity
Dermatologists generally consider that the risk to the skin becomes significant from a UV index of 3.
In spring, the UV index can already reach 3 or 4 in the middle of the day, even when the temperature remains cool.
For most skin types, brief exposure is generally well tolerated. However, beyond about fifteen to twenty minutes in direct sunlight, the application of sun protection is recommended, especially for fair skin.
💡Small tip: the daily UV index is usually shown in your smartphone’s weather app.
Why are the first sun exposures important for the skin?
After winter, the skin is not used to sun exposure.
Exposing oneself for long periods with the sole aim of tanning can therefore represent significant stress for the skin.
The key is progressiveness.
Short exposures allow the skin to gradually activate its adaptation mechanisms, particularly the production of melanin and a slight thickening of the epidermis.
This adaptation allows the skin to better tolerate sun exposure. However, even when skin begins to tan, natural protection remains limited and never replaces appropriate sun protection.
Sun and skin: what really happens
A sunburn is not just a temporary redness. It is an inflammatory reaction caused by cellular damage related to UV exposure.
Over time, repeated exposure accelerates skin ageing and increases the risk of skin cancers.
These effects are largely related to the damage that UV rays cause to the DNA of skin cells.
The sun can also change the appearance of the skin:
scars or imperfections can darken
some pigmented spots become more visible
photosensitivity reactions may occur
acne may seem to improve temporarily before reappearing more intensely
When exposure is excessive, the skin's barrier function can be weakened. The skin then becomes drier, more sensitive, and recovers less easily.
The skin barrier: the first system of protection for the skin
The skin has its own defence mechanisms.
At the heart of these mechanisms lies the skin barrier, made up of a precise organisation of cells and lipids in the upper layer of the epidermis.
When this structure is intact, it helps the skin to maintain its hydration and preserve its balance.
UV radiation can gradually alter this lipid organisation. The skin then retains less water and becomes more sensitive.
A skin with a properly functioning barrier is better at resisting external aggressions and recovers more easily after exposure.
Preserve rather than correct
At Siprès, we believe that the skin functions best when its natural balance is respected.
Rather than trying to correct the effects of the sun afterwards, we focus on what allows the skin to remain resilient over time: the quality of its skin barrier.
Our products are formulated from fresh, cold-pressed vegetable oils sourced directly from Belgian and French farmers. These oils contain lipids that are naturally compatible with those that make up the skin.
When preserved, these lipids help to maintain skin that is supple, comfortable, and more resilient against external aggressions.
The sun is part of life.
It influences our energy, our rhythm, and our skin.
The challenge is not to avoid the sun, but to learn to expose oneself to it with precision.