Sunscreen Reapplication

Sunscreen reapplication is the practice of applying sunscreen again during the day, rather than relying on a single morning application, to maintain protection against ultraviolet light. The protection a sunscreen provides does not last the whole day, so a single morning layer gradually becomes less effective.

Several factors reduce a film of sunscreen over time: it can be rubbed off by contact with clothing or hands, sweated away, removed by towelling, and broken down by exposure to light. Because of this, reapplication is generally advised roughly every two hours during ongoing sun exposure, and sooner after swimming, sweating heavily or towel-drying. Indoors and away from windows, the need is lower.

• Reapply approximately every two hours when spending time outdoors.
• Reapply after swimming, heavy sweating or drying the skin with a towel.
• Use enough product for even coverage; thin application reduces the protection achieved.

Reapplying over makeup can be practical using formats such as powders, sprays or cushions, though these are only useful when applied in sufficient quantity. Sunscreen is one component of sun protection, alongside shade, protective clothing and avoiding peak-intensity hours. Consistent use, together with reapplication, supports the goal of limiting cumulative sun damage over time.