Dermatologists Explain When to Wear Sunscreen Indoors

Experts share advice on protecting your skin from UV rays, even when you're not outside.

Apr. 1, 2026 at 2:19am

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Dermatologists unanimously agree that wearing sunscreen daily, even when indoors, is crucial for protecting skin from UV damage and preventing issues like premature aging, sunspots, and skin cancer. They explain that UVA rays can still penetrate through windows, and certain medications and skincare products can increase sun sensitivity. The experts recommend using a mineral-based sunscreen with an SPF of 30 or higher every day, reapplying as needed.

Why it matters

Many people are unaware that UV exposure can occur indoors, leading to long-term skin damage. This guidance from dermatologists is important for raising awareness and encouraging consistent sunscreen use to maintain skin health, especially for those with a history of sun sensitivity or skin cancer.

The details

According to the experts, even though UVB rays that cause sunburns are mostly blocked by window glass, UVA rays that contribute to photoaging and pigmentation can still penetrate. This is particularly relevant for people prone to issues like melasma, post-inflammatory hyperpigmentation, or lupus, where low levels of light exposure can worsen discoloration. The dermatologists stress that sunscreen should be worn daily, no matter the weather or if you're indoors, and reapplied as directed on the product label, especially if you'll be near sunny windows or doing errands outside.

  • UVA rays remain present year-round, even in the winter.

The players

Tracy Evans, M.D., M.P.H.

A board-certified dermatologist and medical director of Pacific Skin and Cosmetic Dermatology.

Kseniya Kobets, M.D.

Director of Cosmetic Dermatology at Montefiore Einstein Advanced Care.

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What they’re saying

“The most important anti-aging step you can make is wearing sunscreen daily. It is also protective for sun damage, pre-cancers, and skin cancer. It needs to be applied every day and reapplied if you're out in the sun, otherwise it is not as effective.”

— Tracy Evans, M.D., M.P.H., Board-certified dermatologist

“Standard window glass blocks most UVB radiation, but it can allow a significant portion of UVA radiation to pass through, which can contribute to photoaging and hyperpigmentation.”

— Kseniya Kobets, M.D., Director of Cosmetic Dermatology

What’s next

Experts recommend speaking with a dermatologist to determine the best sunscreen and application routine for your individual skin type and needs.

The takeaway

Wearing sunscreen daily, even when indoors, is crucial for protecting skin from the long-term effects of UV exposure, which can occur through windows. This guidance is especially important for those with sun-sensitive skin conditions or a history of skin cancer.