Skin cancer (melanoma)

What's in your sunscreen?

Sunscreen protects you against ultraviolet (UV) light from the sun. This light may make skin cells (called melanocytes) grow out of control, causing a melanoma.

There are two kinds of UV light: UV-A and UV-B. Some ingredients in sunscreen protect you against one type of UV light and not the other. Some ingredients protect against both. And some are specialized. They give you protection against specific types of UV-A light, known as UV-A I and UV-A II. All of these types of light may cause melanomas.

Source:
Moloney FJ, Collins S, Murphy GM.
Sunscreens: safety, efficacy and appropriate use.
American Journal of Clinical Dermatology. 2002; 3: 185-191.

How does sunscreen work?

Sunscreen protects your skin from UV light in two main ways:

Source:
Moloney FJ, Collins S, Murphy GM.
Sunscreens: safety, efficacy and appropriate use.
American Journal of Clinical Dermatology. 2002; 3: 185-191.

It soaks up certain types of UV light before they can damage your skin (often the ingredients will soak up UV-A or UV-B but not both)
It reflects UV light away from your skin.

You can use the list below to find out how well your sunscreen protects you.

Source:
Levy SB.
Sunscreens and photoprotection.
August 2006. Available at http://www.emedicine.com (accessed on 27 September 2007).

For example, Coppertone Sunblock Lotion SPF 15 UVA/UVB Protection has octyl methoxycinnamate and oxybenzone. So it protects you against UV-B and UV-A II, but not UV-A I.

Ingredient	Type of UV light that it prot ects you against
Aminobenzoic acid (also called PABA)	UVB
Avobenzone (often called Parsol 1789)	UVA I
Cinoxate	UVB
Dioxybenzone	UVB, UVA II
Homosalate	UVB
Menthyl anthranilate (Meradimate)	UVA II
Octocrylene	UVB
Octyl methoxycinnamate	UVB
Octyl salicylate (Octisalate)	UVB
Oxybenzone	UVB, UVA II
Padimate O	UVB
Phenylbenzimidazole sulfonic acid (Ensulizole)	UVB
Sulisobenzone	UVB, UVA II
Titanium dioxide	All types
Trolamine salicylate	UVB
Zinc oxide	All types

Sources for the information on this page:

Moloney FJ, Collins S, Murphy GM.Sunscreens: safety, efficacy and appropriate use.American Journal of Clinical Dermatology. 2002; 3: 185-191.

Levy SB.Sunscreens and photoprotection.August 2006. Available at http://www.emedicine.com (accessed on 27 September 2007).

This information was last updated on Sep 01, 2008

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment.
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