This summer, a growing number of social media users, particularly on TikTok and Instagram, have started tracking the daily UV index. Many are using this information not to avoid sun exposure but to seek out times when the sun’s rays are strongest in hopes of achieving a tan. At the same time, some influencers have questioned the safety and necessity of sunscreen use, prompting concerns among dermatologists.
Y. Linda Liou, DO, an assistant clinical professor in the Department of Dermatology at UC San Diego School of Medicine, addressed these trends and explained their potential risks.
“I actually love that people are paying attention to the UV index — it means they’re thinking about sun exposure. But what worries me is how it’s being used: instead of avoiding high UV times, people are chasing them to tan faster. A tan may look like a glow, but it’s really your skin’s SOS signal that DNA damage has already happened. You don’t see it right away, but the harm is happening underneath,” said Dr. Liou.
She described the UV index as “basically a weather report for how strong the sun’s radiation is.” The scale runs from 1 to 11+, with higher numbers indicating increased risk for skin damage. “At a UV index of 11, for example, some lighter skin tones can burn in under 5 minutes. But even if you are darker skinned and you don’t burn easily, your skin cells are still getting hit with invisible radiation damage.”
Dr. Liou noted that both short- and long-term consequences can result from deliberate tanning during peak UV hours. These range from immediate effects like sunburns and cold sore outbreaks to longer-term problems such as wrinkles, uneven pigmentation, and heightened risk for life-threatening skin cancers like melanoma.
“And just to be clear — no skin tone is immune,” she said. “Darker skin tones don’t burn as easily, but UV damage still builds up and can lead to hyperpigmentation or skin cancers that are often diagnosed later because people don’t expect them.”
The idea that a “base tan” provides protection is another misconception Dr. Liou addressed: “One of the biggest myths is that a ‘base tan’ protects you. The truth is, a tan is your skin’s response to damage — it translates to your cells pumping out melanin…to shield the rest of your skin cell from more injury. That tiny bit of protection is nowhere near as strong as sunscreen…Even the darkest natural skin tones don’t block UV completely.”
On recent claims circulating online about sunscreen being harmful or unnecessary, Dr. Liou said: “It’s easy to feel overwhelmed by all the mixed messages online. But here’s the fact: sunscreen is safe, effective, and one of the simplest ways to prevent skin cancer and premature aging.”
She responded directly to common myths:
“Sunscreen is toxic and harmful: Some studies in mice found signs of malignant transformation when animals were exposed to very high doses of certain ingredients in chemical sunscreens under conditions that don’t reflect typical human use. Those results don’t translate to everyday, real-world applications on people. If you want to minimize any of those risks, mineral sunscreens (zinc oxide, titanium dioxide) are great alternatives.
Sunscreen is bad for the environment: Not all sunscreens have a negative impact on coral reefs. Only certain chemical blockers such as oxybenzone and octinoxate have been found to be associated with coral bleaching. If you want to be more conscientious about the environment but still stay protected, look for mineral sunscreens or ‘reef-safe’ options.
Sunscreen will cause vitamin D deficiency: The truth is, the sun is a really unreliable way to get vitamin D because it varies by season, skin tone and geography — and the UV damage outweighs the benefits. A vitamin D supplement is a safer, more consistent choice.”
Dr. Liou added advice for those who want protection while enjoying sunny days:
“You don’t have to avoid the sun completely, just be smart about it:
Stay in shaded areas when possible and try to do outdoor activities before 9 a.m. or after 4 p.m., when the UV index is lower.
Check the UV index on your phone. If the UV index is greater than 3, you should have some form of sun protection…Don’t let clouds fool you: UV radiation is still present on overcast days…
The bread and butter of ‘wear sunscreen and a hat’ is still important…Go for broad-spectrum SPF 30 or higher…Reapply every 90 minutes…
There are many fun stylish options for photo-protective clothing…If you don’t want to buy new clothes there’s even a laundry additive called SunGuard that adds UV protection…
There is a fern-derived dietary supplement polypodium leucotomos that offers some added protection but it’s only a backup never a replacement for sunscreen and shade.”
