Friend and foe: The dual role of sunlight on overall health | AAD 2026

Sunlight often gets a bad reputation, especially at a dermatology conference, but as experts emphasized during this morning’s session at the 2026 American Academy of Dermatology (AAD) Annual Meeting, its role in human health is far more nuanced.

The session, titled Sunlight: Friend or Foe, featured Henry W. Lim, M.D., senior vice president of academic programs at Henry Ford Health in Detroit, and Yolanda Gilaberte, M.D., head of the dermatology department at Miguel Servet University Hospital in Spain. Lim, who was awarded the AAD Gold Medal at the meeting’s opening ceremony on March 27, joined Gilaberte in exploring both the risks and benefits of sunlight exposure. Their central message: effective sun protection advice must be individualized.

A patient’s risk for sun-related damage depends on several factors, including skin tone, geographic location and time of day. Lim began by outlining the composition of sunlight and its relevance to dermatologic health.

“Ultraviolet (UV) light is the one that is most well-known, but UV is actually only 2% of the sunlight reaching the surface of the earth,” Lim said.

In contrast, visible light accounts for approximately 47% and infrared light approximately 51%. While UV radiation has long been associated with skin cancer and photoaging, visible light is increasingly recognized for its own photobiologic effects.

Visible light can contribute to tanning and sunburn, also known as solar erythema, though its impact varies by skin tone. In individuals with darker skin, visible light tends to cause immediate pigment darkening, but with less intense inflammation. In lighter skin tones, visible light exposure is more likely to trigger rapid sunburn, which may resolve more quickly but can still contribute to cumulative damage.

Lim also noted that darker skin provides a degree of natural protection due to higher melanin content. Melanocytes create a denser barrier against radiation, reducing susceptibility to sun damage and slowing visible signs of aging such as wrinkles. However, he cautioned that this does not eliminate risk entirely.

Gilaberte then shifted the discussion to the benefits of sunlight, emphasizing its essential role in overall health. Moderate exposure supports vitamin D synthesis, helps regulate circadian rhythms, and may enhance immune function.

“It’s very well known, the effect of sunlight on the immune system and also on infections, especially respiratory infections,” Gilaberte said. “Sunlight also contributes to the production of melatonin, and there are many organs in our body that contain receptors for melatonin.”

She also highlighted the psychological effects of sunlight, particularly in the context of seasonal affective disorder, which is more common during darker winter months.

“Light therapy is recognized as a first-line treatment for seasonal affective disorder,” she said. “Patients can be exposed either to a lamp that mimics natural daylight or to natural daylight itself, such as going out for a morning walk.”

Despite these benefits, both speakers stressed the importance of comprehensive photoprotection. Lim described a “photoprotection package” that goes beyond sunscreen to include protective clothing, wide-brimmed hats and sunglasses.

Sunscreen recommendations should also be tailored to the individual. Those with lighter skin tones are generally advised to use a daily sunscreen with an SPF of at least 50, while individuals with darker skin tones may opt for SPF 30, depending on their risk profile.

“In the United States, one of the best sunscreens to protect against both UV and visible light is tinted sunscreen,” Lim said, noting that these products often contain iron oxides that enhance protection.