Many sunscreen manufacturers use zinc oxide as a UV blocker. The substance is repeatedly discredited for being harmful to health. With us, you will learn how questionable the use of zinc oxide in sunscreen is.

The compound of zinc and oxygen (ZnO) is one of the most commonly used UV blockers – many companies use zinc oxide in their sunscreen products, such as sun creams. Here’s what makes the fabric so effective as a UV blocker:

• Zinc oxide protects the skin from both Sun – UV-B rays and UV-A rays from the sun by reflecting the light on the skin.

The UV blocker is photostable, so it does not break down under UV radiation. It can maintain its protective effect over a longer period than many other blockers. The sun protection factor also tells you how long you are protected from the sun by sunscreen.

Like titanium oxide, zinc oxide is a mineral UV blocker. There is a risk of allergic reactions with chemical blockers, which is very low with zinc oxide.

How serious is zinc oxide in sunscreen is

Zinc oxide acts as a UV blocker in sunscreens. However, many scientists criticise the form in which it is found in sunscreens. Initially, the blocker has high opacity and would turn the skin completely white when applying sunscreen. To counteract this, zinc oxide is used in sunscreens as nanoparticles. These nanoparticles are suspected of being harmful to health:

• When nanoparticles enter the body, they are deposited in the organism and can cause damage to health. It is unclear whether nanoparticles can penetrate the upper layers of the skin.

Most studies and scientists deny this point, but there are also opposing opinions. According to a survey, the following is likely:

• The smaller the particles, the higher the probability they can get into the organism. Injured and vulnerable skin supports this risk.

Particle size of 330 nm (nanometers) is used as a guideline. Sunscreens with smaller particles should be avoided as they may penetrate the skin. In most cases, you have to inquire directly with the manufacturer about the exact sizes.

Also worrying is that zinc oxide can form free radicals in connection with sunlight. These can attack DNA, but many manufacturers specially coat the particles, so there is little danger. Manufacturers of nanoparticle cosmetic products are forced to label these ingredients based on the INCI (International Nomenclature of Cosmetic Ingredients) guideline. Consequently, you can recognise these products. “(nano)” is added after the substance name.

Sun sprays with nanoparticles are considered to be significantly more harmful than Skincare creams. Inhalation of particles may cause respiratory or lung irritation. In this case, it is advisable to refrain from using it. Scientists disagree about the danger of zinc oxide. There is always a small residual risk. It is not advisable to use it on irritated or “weak” skin. According to most studies, there is no risk to healthy skin, but the risk cannot be completely ruled out. However, it would help if you always avoided sun sprays with nanoparticles.