Why Does Skin Smell After Sun/UV Exposure?

We’ve all experienced that sun-kissed sensation after a beautiful day outdoors, but have you ever noticed a distinctive smell on your skin after exposure to the sun? It’s a unique scent that is neither bad nor sweaty – a smell that seems to be as much a part of summer as blooming flowers and ripening fruit. But what causes this peculiar phenomenon? Why does our skin develop a particular scent after basking in the sunshine? There isn’t a precise answer to this question yet.

First, it’s crucial to understand that our skin hosts a diverse range of bacteria, collectively known as the skin microbiome. These bacteria metabolize compounds in our sweat and sebum (the oil our skin produces), releasing byproducts that can have a distinct smell. The heat from the sun intensifies this process by increasing sweat production, providing more “food” for the bacteria and thereby enhancing their activity. This combination of factors can contribute to the unique “sun-exposed” smell many of us experience.

The distinctive aroma you may perceive after spending time under the sun is probably a result of an intriguing combination of factors such as bacteria, sweat, sebum, UV radiation, and potentially the synthesis of Vitamin D. UV radiation plays a vital role in stimulating our bodies to generate Vitamin D, an essential substance for preserving robust bones and a well-functioning immune system. Although it’s unclear if the production of Vitamin D has a specific scent, it’s plausible that this process might add to the overall fragrance of skin that’s been exposed to the sun.

This spring, I noticed that the specific smell of my body after being in the sun became more intense. Even after spending just ten minutes in the sun with my arms exposed, they start to smell like a suntan. I wondered what could be causing this increase in smell? This year, I started taking 5000 IU of vitamin D3 per day. Could the increased level of vitamin D3 in my body be intensifying the suntan smell?

People who frequent tanning beds also report a distinctive “after tan odor,” or ATO. This smell isn’t due to burnt skin, as some might think, but can be linked back to the bacteria on the skin’s surface reacting to the intense UV light exposure. Many tanning lotions contain antibacterial agents designed to eliminate this after tan odor. But for sunbathers, a simple rinse in the shower and a good moisturizer can also help manage the smell.

In addition, some sun sensitizers can cause side effects when exposed to the sun and can potentially contribute to ATOs.