Sunscreen mistakes and how to avoid them

Kevin Choong, MD

Surgical Oncology

You know sunscreen is important in protecting your skin against cancer and aging, but are you using it correctly? Surgical oncologist Kevin Choong, MD, explained some common sunscreen mistakes, why sunscreen is important and how to make sure your skin is protected.

Why is it important to use sunscreen?

“Melanoma is caused by UV radiation, and this is most commonly due to sun exposure,” Dr. Choong said. “The UV radiation causes damage to the cells and their DNA, ultimately causing a cancer. The best way to prevent a melanoma is to prevent exposure to UV radiation by limiting sun exposure, wearing protective clothing and applying sunscreen.”

How does sunscreen protect you?

Although there are many different brands of sunscreens, generally their active components fall into two major categories: UV blockers and UV absorbers, meaning the sunscreen can either block or absorb the radiation to prevent the damage to your cells.

UV blockers are the thicker creams that contain zinc oxide or titanium oxide. These are known as physical sunscreens that act as a shield and sit on top of your skin in a white layer.

Absorbers are chemical sunscreens that become clear as you rub them in. They contain a variety of compounds that absorb the radiation.

What type of sunscreen is most effective?

“While there are two types of sunscreens, one is not necessarily more effective than the other,” Dr. Choong said.

He said make sure you’re using a sunscreen with an appropriate SPF, or sun protection factor. Typically, an SPF of at least 30 is recommended.

“In a laboratory setting, the higher the SPF, the longer it would take for the same amount of sun to cause a sunburn. However, oftentimes from a practical standpoint, how you use it is more important than what is contained within it,” he said.

What common sunscreen mistakes do people make?

Dr. Choong said the biggest mistake people make is missing spots when they apply their sunscreen.

“To avoid missing those hard-to-reach areas, particularly on your back, have someone else help you when applying the sunscreen,” Dr. Choong said.  

The second most common mistake is not reapplying the sunscreen as directed. In general, you want to reapply the sunscreen every two hours. However, certain activities such as swimming, sweating or toweling off can increase the rate at which the sunblock comes off of the skin, so you’ll need to reapply more frequently to allow for ongoing protection.

Also, be sure you’re following the application instructions, which typically advise waiting about 20 minutes after application before going out in the sun to make sure the sunscreen has adhered to your skin.

Is it okay to use expired sunscreen? Can sunscreen be bad for you?

Using expired sunscreen is not recommended as some of the active ingredients may have degraded and no longer be as effective.

As to whether sunscreen can be harmful, Dr. Choong said there have been some anecdotal descriptions of potential toxicities from the components of sunscreen, such as neurotoxicity, vitamin D deficiency or endocrine dysfunction. However, there is no strong evidence to suggest significant toxicity with the routine use of sunscreen for anyone older than six months.

Is it better to wear sun protection clothing than sunscreen?

“When worn correctly, UV protective clothing can provide more benefit than sunscreen, mainly because you don’t have to worry about reapplying the sunscreen,” Dr. Choong said.

A common mistake, however, is assuming that regular clothing will provide the same amount of protection as specially designed UV-protective clothing. Generally, clothing made of natural materials like cotton, or loosely woven fabric, doesn’t provide much benefit.

Do you even need sun protection if you have dark skin?

“Although high amounts of melanin, which is the protein produced by the melanocytes, is protective against ultraviolet radiation, people with dark skin can get skin cancer,” Dr. Choong said. “This is particularly in areas like the palms of the hands or soles of the feet and under the nails, which lack pigmentation.”

The bottom line when it comes to preventing sunscreen mistakes

Properly using sunscreen is super important in preventing skin cancer, so make sure you’re applying it on all sun exposed skin and reapplying every two hours. You can also use sun protection clothing for even more protection.