A new study by British scientists has found that sunscreen does not prevent the sun’s ultraviolet rays from reaching the skin, breaking with the conventional wisdom that “sunscreen is a reliable way to prevent skin cancer”. The study shows that although sunscreen can prevent sunburn and short-term sunbathing effects, over a long period of time, it cannot prevent UV rays from penetrating the skin and causing potentially fatal diseases. Experts warned, “Anyone in the sun for even a short period of time should make sure they cover themselves up and should not rely on sunscreen alone.” The University of Manchester and the Institute of Cancer Research in London carried out the world’s first molecular study of malignant melanoma, the deadliest form of skin cancer. Their paper, published in the journal Nature, tells how even the highest-rated SPF50 sunscreen cannot stop large amounts of UV radiation from passing through the skin and thus damaging the DNA in the skin’s pigmented cells. Richard Marais from the University of Manchester found that “UV rays can damage the genes that protect us from it, and this shows how dangerous such carcinogens can be.” Although sunscreen does not eliminate skin cancer, Prof. Marais advises that people should stick to sunscreen because, although it does not offer complete protection, it can slow down the cancer-causing effects of UV rays. But he said no one should rely solely on sunscreen to protect them from skin cancer. He says: “The point of this work is to combine the application of sunscreen with other strategies to protect our skin, including wearing hats and loose-fitting clothing and seeking shade when the sun is at its hottest.” One key discovery that Prof. Marey says he has made is the “gene guardian” P53, a protein that is activated when we are exposed to the sun to protect our skin from UV radiation. But solar radiation knocks out the skin’s guardian, P53, and it is impossible for sunscreen to block UV rays and thus provide protection. In conclusion, to minimize the risk of skin cancer, we need to change the old concept of “one bottle of sunscreen for everything” and stick to sun protection measures, the first choice is to avoid the sun, the second is to wear sun hats, T-shirts and pants, and the third step is to use sunscreen.