Because of such mistakes, sunscreens often lose their protective effect

The wrong application of sun creams has dangerous consequences

Sunscreens should protect the skin from the harmful effects of sunlight, especially in summer. Researchers have now discovered that most people benefit from less than half of the expected protection from harmful ultraviolet rays. The fault is a wrong application.

The researchers at King's College London found in their recent research that the typical way in which most people use sunscreen is to prevent our skin from being effectively protected from ultraviolet rays. The experts published the results of their study in the English language journal "Acta Dermato-Venereologica".

Adequate sun protection can be achieved by applying the correct thickness of sunscreen and the correct sun protection factor. (Image: Markomarcello / fotolia.com)

In which thickness sunscreen must be applied?

Most people misuse sunscreen. As a result, the protective effect reaches only 40 percent of the protection that would be expected from the sun protection factor. The current study found that protecting the skin from the harmful UV-induced DNA damage that underlies cancers was significant only when the sunscreen was applied at a thickness between 1.3 and 2.0 milligrams per square centimeter. However, most people only apply 0.75 milligrams, the scientists explain.

Higher sun protection factor can compensate for too thin application

Most skin cancers are caused by DNA damage from sunlight due to UV radiation. People can increase their sunscreen by using sunscreen with a higher sun protection factor. This could compensate for a too thin application of the cream, explain the experts. Given that most people do not use sunscreen as stated by the manufacturers, people should simply use a much higher sun protection factor than they think necessary, study author Professor Antony Young of King's College London is told by the English-language newspaper Quoted "The Guardian".

As a rule, too little sunscreen is applied

The sun protection factors given are based on the assumption that sunscreen is applied to a thickness of two milligrams per square centimeter. This would be the recommendation of the manufacturer. But the average user usually uses much less sunscreen.

From SPF 20 can quickly become SPF factor four

For example, if people use sun protection factor 20 and apply the cream at just 0.75 milligrams per square centimeter, their actual level of protection is about four, which is the sun protection factor of four. To investigate the protective effect of sunscreens in both normal and inadequate use, researchers measured the amount of DNA damage in the skin of 16 volunteers.

How was the investigation done??

The study participants were divided into two groups of eight. One group received only a single dose of UV radiation to mimic normal sunlight. The second group received multiple doses of UV radiation over a period of five days to mimic a continuous vacation exposure. During the experiment, the scientists varied the amount of UV radiation in order to reproduce the conditions in classic holiday destinations such as Tenerife.

Sunscreen used complied with EU regulations

Volunteers received their UV radiation dose within 15 minutes of applying their sunscreen, and the skin biopsies were taken immediately after UV irradiation, the physicians explain. The sunscreen used in the study was in line with EU legislation.

Effective protection through proper application

The skin biopsies carried out showed that the participants from the holiday group who applied the sunscreen in the higher thickness recommended by the manufacturer had significant protection against damage even after a high UV dose for several days compared to subjects who only had a thin skin Had applied layer of sunscreen. It is undisputed that sunscreens provide important protection against the carcinogenic effects of the sun's ultraviolet rays, says Young. The study shows, however, that the way the sunscreen is applied plays an important role in determining its effectiveness, the expert adds. (As)