(NEXSTAR) — We’re all familiar with the reminders to wear sunscreen when the summer months come around. And you may also find yourself, begrudgingly at times, lathering on the sunscreen before heading out to the waterpark, beach or other summer-time events.
But properly applying sunscreen is more than just spraying a quick layer on the arms or rubbing around a white glob of lotion. You may be, inadvertently, making some mistakes when it comes to sun protection.
Here are five things you may be doing wrong with sunscreen.
1. Not using sunscreen at all
Unsurprisingly, not using sunscreen at all when you’re in the sun can be a big misstep. Despite recent claims on social media that wearing sunscreen causes cancer, health officials say using it actually prevents cancer.
“As far as we know, the sunscreen ingredients sold in the U.S. are FDA-approved and none of them have been linked to cause cancer,” Dr. Shilpi Khetarpal, a dermatologist with Cleveland Clinic, explained to Nexstar, adding that “by not wearing sunscreen, [you] are increasing their risk of developing skin cancer, specifically basal cell and squamous cell.”
Research has shown sunscreen can protect against common skin cancers, though the degree of protection will vary based on the UV radiation associated with the formation of the skin cancer.
2. Not using enough sunscreen
If No. 1 doesn’t apply to you (because you are applying sunscreen), this might: not wearing enough sunscreen.
According to Khetarpal, an adult, full-body application of sunscreen is one ounce — or, the equivalent of a shot glass. If you’re using a spray-on sunscreen, she recommends spraying until your skin glistens.
“The bottom line is apply more than you should, or just make sure you’re applying liberally and generously,” Khetarpal said.
3. Putting sunscreen on at the wrong time
You can put on as much sunscreen as you want, but if you wait until the end of your day at the beach to apply, you likely won’t fare well.
When you should put on the sunscreen will depend on what you’re doing outside. For example, if you’re going to sit on your patio, you’ll want to put on the sunscreen before stepping outside — it will start working “relatively quickly,” according to Khetarpal.
If you’re going to be sweating, swimming, or otherwise interacting with water, you’ll want to apply the sunscreen 30 minutes ahead of time. This will allow the water-resistant effect to kick in.
4. Forgetting to reapply sunscreen
In addition to putting on the correct amount of sunscreen with enough time for it to take effect, you’ll most likely need to reapply.
If you aren’t sweating or getting wet, you’ll want to reapply every two hours, Khetarpal said. If you are getting wet, she recommended reapplying after you’ve come out of the water — be sure to pat yourself dry first. You may choose to reapply before the two hour mark, especially if you’re sweating.
5. Using the leftover sunscreen bottle from last year
Maybe you found a partially-used bottle of sunscreen from last summer in your closet. Before you use it, Khetarpal recommends checking the expiration date.
Like food, after the expiration date has passed, the quality of the sunscreen has likely decreased. According to Khetarpal, sunscreen does lose efficacy past the expiration date. At that point, you’ll want to buy a new bottle.
When it comes to picking the best sunscreen, experts recommend looking for one that is broad spectrum with an SPF of at least 30. If you’re going to be swimming or sweating, you may also want to opt for a sunscreen that is water-resistant.
You may also want to check the ingredients. Sunscreens with zinc oxide and titanium dioxide work like a shield, reflecting the rays off your skin. Those with chemicals like oxybenzone and octinoxate work more like a sponge, absorbing the sun and breaking it down.
It’s worth noting that oxybenzone and octinoxate are among a group of chemicals commonly used in sunscreen that are not considered GRASE, or “generally recognized as safe and effective” by the Food and Drug Administration. Instead, the agency says “additional data is needed to show” sunscreens containing the chemicals “are GRASE.”
The FDA notes, however, that this does not mean oxybenzone and octinoxate are unsafe to use in sunscreens. More information is necessary to determine whether they are GRASE. The Centers for Disease Control and Prevention advises using sunscreens with less than 5% of either.
Zinc oxide and titanium dioxide are considered GRASE ingredients because the FDA “has found sufficient safety data … to support a proposal that sunscreen products containing these ingredients (at concentrations of up to 25%) are GRASE.”