How much sunscreen should be applied? How often should it be reapplied?

Warn your patients that most people apply too little sunscreen. To cover the face, arms, legs, and upper torso of an average-sized adult requires 1 ounce of sunscreen, which is generally a handful. A smaller person or child needs proportionally less. Sunscreen should be applied evenly and rubbed into all exposed skin. It should be applied 30 to 60 minutes before sun exposure. Then a second layer should be applied at the beginning of sun exposure and, under normal conditions, reapplied every 2 hours. Sunscreen should be reapplied more often if swimming, sweating, or rubbing has removed some of the product. Warn patients that reapplication does not double the SPF and to not rely on redness as a signal to reapply sunscreen. Skin damage occurs before sunburn appears.