5 common sunscreen mistakes — and how to avoid them

Skin cancer is the most common cancer in the United States, affecting one in five Americans in their lifetime. Yet most cases of skin cancer can be prevented by protecting your skin from the sun’s harmful ultraviolet rays. The best way to do this is by seeking shade, wearing protective clothing, and applying a broad-spectrum, water-resistant sunscreen with an SPF of 30 or higher.

However, in a survey, the American Academy of Dermatology found that 65% of people say they often forget to reapply their sunscreen — leaving people vulnerable to dangerous ultraviolet radiation from the sun. For example, the AAD found that only about a third of Americans reapply their sunscreen every two hours while outside. Since sunscreen wears off, incorrect usage can leave you unprotected and susceptible to skin cancer.

To protect your skin and reduce your risk of skin cancer, below are five common sunscreen mistakes — and how to avoid them:

1. Ignoring the label. There are a variety of sunscreens on the market. To effectively protect yourself from the sun, the AAD recommends looking for sunscreens that are broad-spectrum, water-resistant, and have an SPF of 30 or higher.

2. Using too little. Most people only apply 25-50% of the recommended amount of sunscreen. However, to fully cover their body, most adults need about one ounce of sunscreen – or enough to fill a shot glass. Apply enough sunscreen to cover all skin that isn’t covered by clothing. Apply the sunscreen 15 minutes before going outdoors, and reapply every two hours while outdoors or after swimming or sweating.

3. Applying only in sunny weather. Alarmingly, the AAD found that only about 20% of Americans use sunscreen on cloudy days. However, the sun emits harmful UV rays all year long. Even on cloudy days, up to 80% of UV rays can penetrate your skin. To protect your skin and reduce your risk of skin cancer, apply sunscreen every time you are outside, even on cloudy days.

4. Using an old bottle. The FDA requires that all sunscreens retain their original strength for at least three years. Throw out your sunscreen if it’s expired or you’re unsure how long you’ve had it. In the future, if you buy a sunscreen that lacks an expiration date, write the purchase date directly on the bottle so that you know when to toss it out.

5. Relying solely on sunscreen. Since no sunscreen can block 100% of the sun’s UV rays, it’s also important to seek shade and wear sun-protective clothing, including a lightweight, long-sleeved shirt, pants, a wide-brimmed hat, and sunglasses with UV protection, when possible. For more effective sun protection, select clothing with an ultraviolet protection factor (UPF) label.

Sunscreen plays an important role in everyone's skin care. It helps prevent sunburn, skin cancer, and premature skin aging, including wrinkles and age spots. To ensure the best protection for you and your family, it’s important to follow the manufacturer’s directions when using sunscreen.

If you have questions about sunscreen, including how to select one for you and your family, talk to a board-certified dermatologist.