Large corporate advertising budgets have convinced most people to apply sunscreens when outdoors to protect against sunburn and the development of skin cancer. Unfortunately, studies have never shown that application of sunscreen prevents skin cancers. Most sunscreens have an SPF or ‘sun protection factor' that supposedly denotes the length of time a user can remain in the sun without sustaining a sunburn. This number gives a false sense of security because it refers only to the sunburn-prevention ability of the product to block ultraviolet B rays. The sun’s energy also includes ultraviolet A rays which also cause skin cancer, damage to collagen and blood vessels in the skin, as well as tanning. SPF sunscreens do NOT block ultraviolet A rays! In fact, no sunscreen on the market today blocks all ultraviolet A rays. Only clothing and a wide-brimmed hat will block all the ultraviolet rays from overhead. But reflected rays bouncing off water, concrete or shiny surfaces can still damage the skin. For all these reasons, it’s best to limit your time outdoors based on your skin type. Darker individuals can safely remain in the sun longer than those with fair skin. In fact, a fair skinned person with green eyes may start to notice reddening of their skin in less than five minutes. Any sunburn or tan puts one at risk of skin cancer and premature aging, and so should be avoided. Topical Vitamin C serum and Vitamin E lotion are effective at blocking some of the ultraviolet A light but hat and clothing are the best insurance against skin cancer development.