Ultraviolet rays from the sun damage the DNA of skin cells, which can lead to cancer. These same rays are also responsible for the synthesis of vitamin D, which plays an important role in immune and bone health. Whether or not a person should apply sunscreen before going outside depends on several factors, including skin color, location, and time of day, reports Health.com
By now, you’re probably aware of the importance of wearing sunscreen if you’re spending a day at the pool or beach. But when it comes to brief exposure to the sun, the rules can seem a little more blurred.
While the American Academy of Dermatology (AAD) instructs people to “apply sunscreen daily to uncovered skin if you’re going to be outside,” a growing online conversation has made it clear that not everyone agrees with this strict approach.
Some people, like reality star Kristin Cavallari, have floated the idea that we shouldn’t be using sunscreen at all. Then there are others, like reporter Rowan Jacobsen, who have argued that some people may not need to use it as often as US guidelines suggest.
His May 10 article in The Atlantic, titled “Against sunscreen absolutism,” focuses largely on Australia’s sun safety guidelines, which were recently updated to align with the premise that a certain amount of time spent in the sun without sunscreen has benefits, primarily in terms of vitamin D exposure.
In light of all the conflicting advice, you might be wondering if it’s always necessary to apply sunscreen every time you venture outside, as US guidelines suggest, or if it’s ever okay—or even beneficial—to spend time in the sun without protection.
Here’s what the dermatologists had to say
Before looking into whether it’s ever healthy to skip sun protection, it’s important to understand how sun protection affects your health to begin with.
Sunscreen works by forming a layer that absorbs ultraviolet B (UVB) radiation from the sun before it penetrates the skin. This radiation can permanently damage the DNA of skin cells, stimulating the formation of a mutation that can become a cancerous cell.
By blocking UVB rays, sunscreen has another effect: When applied correctly, it can limit the body’s ability to produce vitamin D, which plays an important role in immune and bone health.3 You can get some of the vitamin D through diet – and a supplement can fill the gap – but the main natural source of vitamin D is the sun.
In general, fair-skinned people only need about 10 to 15 minutes of sun exposure on their face, arms, and legs a few times a week to get all the vitamin D they need, he told Health. 3 Jonathan Ungar, MD, assistant professor of dermatology and medical director of the Waldman Melanoma and Skin Cancer Center at Mount Sinai.
People with darker skin may need up to 30 minutes longer. This is because darker skin has more pigment, or melanin, which works to protect against UV rays.
However, Ungar said these estimates are “extremely simplistic” and could change based on several factors. For example, UV rays are strongest in spring and summer, in locations closer to the equator and between 10:00 a.m. and 4:00 p.m.
Is it always necessary to wear sunscreen outdoors?
Australia’s new guidelines are largely based on the idea that for some people with darker skin, it may be worth giving up some sun protection to get some vitamin D.
The AAD disagrees with this approach, according to The Atlantic article. A spokesperson told Jacobsen that “because ultraviolet rays from the sun can cause skin cancer, the Academy does not recommend obtaining vitamin D through sun exposure.”
However, Diya Mutasim, MD, a professor in the Department of Dermatology at the University of Cincinnati College of Medicine, told Health that “there is some benefit to getting some sunlight both for vitamin D synthesis and for your mood”.
While he doesn’t think it’s necessary to apply sunscreen before exposure to very short bursts of sun, such as a brisk walk to the car, if you should go outside without sunscreen for longer periods is a more complicated question.
“Ultimately, it’s about finding a balance between risks and benefits, ideally one where the benefits outweigh the risks,” Ungar said. “As I tell my patients, there are two main ways to get vitamin D, sun exposure vs. supplementation. Only one of these is known to increase the risk of skin cancer, but you have to choose for yourself.”
The idea is to reap the benefits of the sun without causing changes in the skin’s appearance, Mutasim said. Slight redness and even tanning indicate sun damage.2
Several factors, including cloud cover, time of day, and season, can influence how quickly you might experience sun damage. Also, people with darker skin are less likely to be affected by the sun (although they can and do develop skin cancer).4
“A person with very fair skin may not tolerate more than five minutes without some protection, while a person with darker skin may tolerate 40 minutes,” Murasim said.
What is clear, Murasim stressed, is that anyone who plans to stay in the sun for an extended period should plan to protect their exposed skin. According to the AAD, this means applying a water-resistant, broad-spectrum sunscreen with an SPF of at least 30.1
