Every person has their own MED, minimal erythemal dose, which means how much times passes without the skin turning red from irritation. Having a sunscreen is essential if you want to keep your skin healthy, therefore you should choose carefully the correct SPF for your skin. We cannot avoid being exposed to the and we need the for vitamins, therefore protecting your skin daily is the best alternative. Everyone has different skin and different tolerance to the exposure and the results will vary from person to person.

The age of the skin is not the same as the age of a person, which will depend on how the person takes care of the skin, and the best treatment is protection. For instance, SPF 4 means four times as long, and that period of time will vary from person to person.

The SPF stands for " protection factor" and that represents how long a person can stay out in the without burning while using the product. However, SPF 15 will provide a fairly high amount of protection, it blocks about 94% of UVB light, however, it does not guarantee the skin to be free from any damage.

Exposure can cause both short and long term effects on the skin.