Prof. Dr. Katerina Damevska

Prof. Dr. Katerina Damevska
Spec. in Dermatovenerology
PHI University Clinic for Dermatology, Cyril and Methodius University, Skopje

When to use products with SPF?

Sun protection products should be used whenever there is UV index above 3. If you are in an environment that reflects light (snow, water surface), use sun protection, even if the UV index is below 3.

Does glass protect against sun rays?

Commercial glass used in buildings and cars blocks almost 100% of UVB rays, but lets through almost 50% of UVA rays. Glass with additional UVA protection is expensive and rarely used. This means that if you work by a window or if you are in a car or even on an airplane by a window, you are exposed to the harmful effects of UVA rays (they penetrate deep into the skin and cause premature aging and various cancers).

If you work in a building with glass walls, make sure the glass blocks UVA rays. If possible, use a glass film labeled as providing UVA + UVB protection to ensure additional protection. If this is not possible, apply a UVA protection product every 3-4 hours.

Some newer cars have UVA-protected windshields, but side and rear windows almost never have UVA protection.

Does clothing protect against UV rays?

Only tightly woven fabrics provide complete protection from UV rays. Transparent thin fabrics do not provide sufficient protection. Special clothing (UV protective fabric UPF) is recommended for people who are sensitive to the sun or have skin diseases that worsen after sun exposure. It can be replaced by combining clothes with applying sun protection products.

UV ray exposure on mountains

You are not protected from UV rays while on a mountain. On the contrary, UV radiation increases the higher you are from sea level. This is especially important in winter or when staying near mountain lakes, which reflect light.

Cloudy and rainy days

It is false to believe that photo protection is not necessary on cloudy or rainy days. While it is true that UVB rays are less intense on cloudy days, UVA rays are unaffected by clouds, rain, and fog.

How to correctly use sun protection products?

You should apply a sufficient amount of the sun protection product on all areas that are not protected by clothing, 20 minutes before sun exposure.

A sufficient amount must be applied for the protection to be effective. The recommended amount is 2 milligrams of cream per square centimeter of skin. In practice, this means that covering the body of an adult requires about 25-35 grams of cream or at least 2 tablespoons. When on the beach, you should reapply every 2 hours because the cream is easily wiped off and washed off when bathing or sweating. In other circumstance, you should reapply every 3-4 hours.


Keep babies in the shade. The use of protective creams is not advised under the age of 6 months. In older children, limit the time of direct exposure to the sun, make sure the skin is covered with clothing and apply a protective cream with SPF of at least 30. At the beach, apply a new layer after swimming because no cream is waterproof.

Кај поголемите деца ограничете го времето на директа експозиција на сонце, погрижете се кожата да е покриена со облека и нанесувајте заштитен крем со заштитен фактор најмалку 30 (SPF 30). На плажа нанесувајте нов слој по капењето затоа што не постои водоотпорен крем.


Our body produces vitamin D when the skin is exposed to UVB rays. The transformation of inert to active vitamin D takes place in the liver and kidney. This process is necessary for calcium absorption and bone health.

There is a dilemma on whether sun protection products prevent the synthesis of vitamin D. Studies show that sun exposure of 10 minutes a day is sufficient for the above physiological processes to occur.