evidence: Too much sun exposure can also raise your risk for skin cancer, the most common type of cancer in the United States. When UV light enters skin cells, it can harm the genetic material (called DNA) within. [...] The best way to protect skin health and prevent skin cancer is to limit sun exposure. Avoid prolonged time in the sun, and choose to be in the shade rather than in direct sunlight. Wear protective clothing and sunglasses, and use sunscreen between 10 a.m. and 4 p.m. Sunscreen is especially important at that time, when the sun’s rays are most intense. [...] Several factors—like cloudy days or having dark-colored skin—can reduce the amount of vitamin D your skin makes. But you can also get vitamin D from foods or dietary supplements. Check with your health care provider about whether you should be taking vitamin D supplements.