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Get the Facts: Maximize Your Sunscreen

May 2009

by Adelina Espat

When purchasing sunscreen, do you ever wonder which SPF is best? Most people want to get the best protection    possible from their sunscreen. Because of the wide selection of sunscreens available today, sometimes making the right choice can be a confusing task.

Choose SPF 30 or higher

hands applying sunscreen

A sunscreen with an SPF (Sun Protection Factor) of at least 30 is a good choice for most people. It’s important to remember that the protection an SPF offers does not increase proportionately with the designated SPF number. SPF 15 absorbs 93% of the sun’s burning rays, while SPF 30 absorbs 97%.

One ounce of sunscreen (about the size of a ping pong ball) is considered sufficient to properly cover sun-exposed areas of the body for most adults. Sunscreen protects the skin from ultraviolet (UV) rays produced by the sun.

The sun’s two harmful rays are:

  • Ultraviolet A (UVA) – rays remain intense throughout the year and all day long
  • Ultraviolet B (UVB) – ray intensity varies throughout the year

UVA and UVB exposure may cause:

  • Skin cancer
  • Premature aging of the skin
  • Harm to the eyes and immune system

To get the most out of your sunscreen, generously reapply throughout the day. This is especially important because factors such as humidity, perspiration and uneven product application can cause sunscreen to lose its effectiveness.

Preparing your skin for a day in the sunBeach Bag

Before leaving your home for a day of outdoor activity, take appropriate precautions to ensure that your skin is well-protected. Susan Chon, M.D., assistant professor in MD Anderson’s Department of Dermatology recommends gathering the following items before heading outdoors.

Sun protection checklist

  • Sunscreen with SPF 30 or higher
  • Lip balm with SPF 30 or higher
  • Hat with a brim or cap
  • Long-sleeved shirt (preferably sun-protective clothing)
  • Sunglasses with UV protection

“These are great items to keep handy in your bag to prepare for the sun as it intensifies through out the day,” Chon says.

Application time line

Chon suggests the following guidelines on when to best use these items.

Morning: 8 – 11 a.m.

Apply Sunscreen with SPF 30 or higher

  • Apply generously and evenly, at least 30 minutes before sun exposure
  • Don’t forget sunscreen needs to be reapplied every two hours
  • Wear a hat, sunglasses and lip balm

Midday: 11 a.m. – 2 p.m. (hottest time of the day)

Seek Shade and Wear Protective Clothing

  • Sit under an umbrella for extra protection
  • Wear a long-sleeved shirt with your hat and sunglasses
  • Don’t forget to reapply sunscreen and lip balm every two hours

Afternoon: 2 – 5 p.m.

Reapply Sunscreen with SPF 30 or higher

  • Keep wearing your hat and sunglasses
  • Don’t forget to reapply sunscreen and lip balm every two hours

“Remember, if you are sweating or swimming, you may need to reapply more often,” Chon says. Avoid reflective surfaces such as water, sand, snow and concrete. “You can burn from indirect exposure to the sun, too,” Chon says.

Sun-protective gear provides added defense

While many people usually carry sunscreen and sunglasses when spending time in the sun, few are aware of the availability of sun-protective clothing that can offer even greater protection from the sun’s harmful rays.

According to Chon, a long-sleeved shirt may offer sun protection; however, most light-weight cotton shirts used in the summer don’t offer more than UPF (Ultraviolet Protection Factor) 10. “Some companies offer an extensive line of sun protective clothing, which can provide as much as UPF 50,” Chon says.

UPF indicates how much UV radiation can penetrate the fabric in clothing. For example, shirt with UPF 30 means that just 1/30th of the sun’s UV radiation can reach the skin.

Choosing the right sunglasses also can provide added UV protection. Choose wrap-around sunglasses that absorb at least 99% of UV rays. “These sunglasses help protect your eyes and the skin around your eyes,” Chon says. 

Chon recommends speaking with a dermatologist to get more information on sun-protective gear.

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© 2014 The University of Texas MD Anderson Cancer Center