1. Antiaging Tips & Secrets Slideshow Pictures
2. Take the Sun Safety Quiz!
3. Take the Skin Quiz

Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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In this Article

• What is sun protection?
• How is sunburn best prevented?
• What is sunscreen?
• What is meant by SPF?
• Are all sunscreens equally effective against UV radiation?
• How do sunscreens work, and which sunscreen ingredients protect against both types of UV radiation?
• How should skin sunscreens be applied?
• Do water or perspiration wash off sunscreen?
• Can sunscreens cause a skin reaction?
• Should everyone use sunscreen protection?
• Can the labels on sunscreen products be trusted in the U.S.?
• Do all tanning products contain sunscreens?
• What kind of sunglasses should be worn?
• Is sunscreen protection necessary in the winter?
• Are a good sunscreen and sunglasses enough?
• Sun Safety FAQs
• Find a local Dermatologist in your town
• Sun Protection and Sunscreens Index

Yes. Therefore, sunscreen should be reapplied at least every two hours when staying outdoors for a prolonged period and after swimming, bathing, perspiring heavily, or drying off with a towel or handkerchief. Water- and perspiration-resistant sunscreens are available. However, even their protection will not last indefinitely.

PABA (para-aminobenzoic acid) was one of the original UVB-blocking products in sunscreens. Some people developed a skin reaction to this chemical, and it was also found to stain clothing. Over the years, PABA has been refined and modified into newer ingredients known as glycerol PABA, padimate A and padimate O, all of which are UVB-blocking sunscreen ingredients. Other ingredients in sunscreens may also increase the risk of a skin reaction in certain people. Anyone can determine the suitability of a particular sunscreen without risk of serious harm by

1. clothing his or her body fully except for a small patch of skin; and then
2. applying the sunscreen to the skin patch and exposing it to sunlight.
3. If a reaction occurs, the user should not use that product. He or she should try another product.

As a general rule, babies 6 months of age or younger should not have sunscreen applied to their skin because their bodies may not be capable of tolerating the chemicals in sunscreens. Instead, they should be kept away from sun exposure.

Everyone over 6 months of age should use a sunscreen regularly unless they and their doctors decide it would be better to protect the skin in other ways.