Sunscreen: truths, myths, and good habits

Sunscreen: truths, myths, and good habits

Summer has arrived, bringing with it more opportunities to spend time in the sun. As every year, common doubts and questions arise: “If I apply sunscreen, will I still tan?”, “Does sunscreen block vitamin D absorption?”, “If I stay under a beach umbrella wearing a hat, can I skip sunscreen?”

Sunscreen is a daily ally, useful in every season. UV radiation causes what is known as skin ageing, but it’s also responsible for sunburns, precancerous and cancerous lesions, and can compromise the skin’s immune defenses, leading to a higher risk of skin cancer.

Solar radiation is divided into three types: UVA, UVB, and UVC. The ozone layer completely filters UVC, about 90% of UVB, and only a small portion of UVA. As this layer thins, the skin becomes increasingly exposed to harmful radiation. UVA rays contribute to ageing and pigmentation, while UVB rays are associated with sunburns and the development of skin cancers.

Blue light and daily protection

Blue light, now widely discussed, is an electromagnetic radiation within the visible light spectrum, with a wavelength between 380 and 500 nanometers. It’s emitted by natural sources like the sun and artificial ones such as electronic devices and LED lighting.

It can negatively affect the skin, eye health, and the body’s circadian rhythm.Sunscreens work thanks to active ingredients that absorb, reflect, or scatter UV rays. Applying sunscreen should be the final step in your daily skincare routine, all year round.

It’s important to choose formulas specifically designed for the face and the body, as skin characteristics differ. For instance, a product formulated for the body, where the skin is thicker, might be too rich for the face and cause clogged pores.

How and when to apply sunscreen

Sunscreen should be generously applied to all exposed areas about 30 minutes before sun exposure, to ensure proper absorption. How often it should be reapplied depends on the season, your activities, and the SPF level.

In summer, it’s strongly recommended to reapply it every two hours and after swimming or heavy sweating. During winter, it’s possible to be more flexible, but if you work near windows or glass surfaces without curtains, the skin still remains exposed to UVA rays, which can lead to long-term effects such as photoaging and cellular damage.

A good sunscreen should have an SPF (Sun Protection Factor) of at least 30, which filters about 97% of UVB rays. SPF 50 provides protection up to 98%.

So why choose an SPF 50?

The SPF number indicates how long a person can stay in the sun without burning. For example, if fair skin begins to burn after 10 minutes without protection, using SPF 30 would allow up to 300 minutes of exposure, and SPF 50 would allow up to 500 minutes—assuming regular reapplication.There’s also SPF 100, which filters about 99% of UVB rays and is ideal for prolonged exposure or very sensitive skin.

Vitamin D and sunscreen safety

A common belief is that sunscreen interferes with vitamin D production. In reality, although it reduces UVB exposure, it doesn’t block it completely, allowing the skin to still synthesize the vitamin.

Scientific evidence shows that it’s possible to maintain adequate levels of vitamin D even with regular sunscreen use.

Another frequent concern is the alleged risk that sunscreens may contribute to cancer. This belief is unfounded. Sunscreens from trusted brands are essential tools for prevention.

Ultraviolet radiation from the sun and tanning beds is among the main recognized causes of skin cancer. International clinical studies have also shown that sunburns during childhood significantly increase the risk of developing skin cancer, including melanoma, even many years later.

For personalized advice on choosing the right sunscreen for your skin, feel free to contact my clinic.