Sunscreens

What are Sunscreens?
Sunscreens are products used to protect the skin from the damaging ultraviolet rays of the sun.

What are the ingredients of a sunscreen?
Most sunscreen products contain combinations of ingredients.
They work by absorbing, reflecting, or scattering some or all of the sun's rays.
Many combinations of synthetic and natural ingredients may go into the formulation of a single sunscreen.
Several types of chemicals are used as sunscreens. They vary by the degree of protection they can provide and the types of ultraviolet light they can block:
• Cinnamates, give low levels of protection, and are only effective against UVB light.
• Para-amino benzoic acid (PABA) compounds, are effective only against UVB light.
• Salicylates, octylsalicylate, and homosalate offer moderate levels of protection against both UVA and UVB light, but the range of light waves against which they protect is relatively narrow.
• Benzophenones, protect against a broader range of ultraviolet light than the salicylates and are more useful for broad spectrum protection.
• Physical sunscreens are really sun blockers and include titanium dioxide, red petrolatum, and zinc oxide. Preparations containing these blockers are thick ointments and are usually reserved for skin areas at high risk of burn, such as the nose.
In addition to the chemical used as a sunscreen, the vehicle can be important in determining how well a product works. Unfortunately, thick, greasy ointments seem to work better than vanishing creams, lotions, or liquids.

What is SPF?
Sun Protection Factor
A number telling how well the sunscreen protects against burning. The higher the number, the longer a person can stay in the sun without burning.