Most sunscreens available over the counter are packed full of chemical UV Filters (such as Oxybenzone and Retinyl Palmitate) which, when heated by the suns UV rays, causes a chemical reaction on the skin. There are concerns that these chemical UV filters may be absorbed into the body through the skin and this reaction could cause more skin problems than it prevents. Research suggests it could possibly be the cause of an escalating rise in skin cancers.
Covering up with sunblock before you even venture outside into the sun will prevents your body from absorbing Vitamin D, and a Vitamin D deficiency can cause infections, depression, osteoporosis and hormonal imbalances.
Common Sense approach: Sunbathe, without sunscreen, in the early or late part of the day for around 20 minutes to get your quota of Vitamin D. If you are going to be in the sun in the middle of the day, cover-up with cotton clothing and a wide brim hat or use a natural sunscreen that you know is chemical free.