It's been known for some time that too much exposure to the sun can damage the skin, but new research carried out in Switzerland suggests that creams applied to the skin - supposedly to protect it from the sun's rays - could also be harmful.
Scientists at the University of Zurich have identified chemicals in sun creams, which although filtering out harmful ultra violet (UV) rays actually speed up the growth of cancer cells.
Twenty-six different chemicals are used in sun creams to filter out UV rays. By absorbing light, the substances form a protective layer on the skin.
Margret Schlumpf's team at the university Institute of Pharmacology and Toxicology tested six of these chemicals on human breast cancer cells and five on rats. They discovered that five substances caused growth in human cancer cells while three other substances caused an expansion of the uterus of pre-pubescent rats.
Tests found that the rats reacted most strongly to the commonly used chemical 4-MBC, which according to Schlumpf was a cause for concern. "We used concentrations within the dosages allowed for sun creams," she said.
Schlumpf said that although the finding was worrying, it was too early to say that the substances actually caused cancer. And she said there was no need for sun-worshippers to panic.
"No one covers themselves from head to toe with sun cream every day," the scientist said. Nevertheless, she advised caution during the summer months and urged people to avoid exposure to the sun during the hottest part of the day.
swissinfo with agencies