It doesn't take much to get the proper amount of vitamin D exposure for the day. As little as 15 minutes can give you the amount of vitamin D your body needs. Sunlight can also penetrate clothing. So yes, sunscreen does block the rays, but as long as you aren't covered in head to toe sunscreen 100 percent of the time (chances are you aren't), it is more than likely you are getting the sunlight you need. So don't use this as an excuse to skimp on the sunscreen!