- With Mayo Clinic dermatologist
Lawrence E. Gibson, M.D.
read biographyclose windowBiography of
Lawrence E. Gibson, M.D.
Lawrence E. Gibson, M.D.
Dr. Lawrence Gibson likens bad health information on the Internet to food poisoning.
Consumers, he says, need to be aware and will find reliable information at MayoClinic.com.
Dr. Gibson, a Covington, Ky., native, has been with Mayo Clinic since 1986 and is board certified in dermatology, dermatopathology and immunodermatology. He is a professor of dermatology at Mayo Medical School and a consultant in the Department of Dermatology.
Dr. Gibson has served as the fellowship director for dermatopathology and as chair of the Laboratory Division in the Department of Dermatology. He is especially interested in inflammatory disorders of the skin, including vasculitis, and in lymphoma affecting the skin.
"Electronic information has become a staple in the diet of a health conscious society," he says. "It's important to avoid misinformation and provide a credible source for health information. Using this analogy, it's critical to avoid 'indigestion' or, worse yet, 'food poisoning' by the ingestion of tainted information."
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Dental care (7)
- When to brush your teeth
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Skin care (9)
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Nail care (4)
- Acrylic nails: Can they harm natural nails?
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Eye care (2)
- Choosing sunglasses: Is UV protection important?
- Eye exam: Is a laser retina scan worthwhile?
Sleep (7)
- How many hours of sleep are enough?
- Sleep aids: Could antihistamines help me sleep?
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Mental health (2)
- Stop multitasking and learn how to focus
- Passive-aggressive behavior: What are the red flags?
Healthy at work (4)
- Shift work: Improving daytime sleep
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Question
Does sunscreen expire?
Is sunscreen from last year still good? When does sunscreen expire?
Answer
from Lawrence E. Gibson, M.D.
Sunscreens are designed to remain stable and at original strength for up to three years. This means that you can use leftover sunscreen from one year to the next.
Some sunscreens include an expiration date, or an indication of when the sunscreen is no longer effective. Discard sunscreen that's past the expiration date, is more than three years old or has been exposed to high temperatures.
Keep in mind, however, that if you use sunscreen generously and frequently, a bottle of sunscreen shouldn't last from one year to the next. Generally, a liberal application is 1 ounce (30 milliliters) — the amount in a shot glass — to cover all exposed parts of the body. If you have a 4-ounce (118-milliliter) bottle, you'll use about one-fourth of it during one application.
To maximize protection, use a broad-spectrum sunscreen with a sun protection factor (SPF) of at least 15. The American Academy of Dermatology recommends using a broad-spectrum sunscreen with an SPF of 30 or more. Apply sunscreen generously 20 to 30 minutes before going outdoors and reapply about every two hours — or more often if you're swimming or sweating. Be sure to rub the sunscreen in well.
Next questionTanning beds: Safer than the sun?
- Prevention. Centers for Disease Control and Prevention. http://www.cdc.gov/cancer/skin/basic_info/prevention.htm. Accessed Dec. 29, 2010.
- The burning facts. Environmental Protection Agency. http://www.epa.gov/sunwise/doc/sunscreen.pdf. Accessed Dec. 29, 2010.
- Facts about sunscreens. American Academy of Dermatology. http://www.aad.org/media/background/factsheets/fact_sunscreen.htm. Accessed Dec. 29, 2010.
- Gibson LE (expert opinion). Mayo Clinic, Rochester, Minn. Accessed Jan. 6, 2011.
- Sun safety: Save your skin! U.S. Food and Drug Administration. http://www.fda.gov/downloads/ForConsumers/ConsumerUpdates/UCM143731.pdf. Accessed March 7, 2011.
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