Forget everything you think you know about setting the mood, and get ready to trade in flickering candlelight for broad daylight. It’s free, it’s warm, and according to new research, it’s a pretty reliable aphrodisiac. A new study shows that exposure to sunlight increases feelings of passionate love (and levels of sexually stimulating hormones) in both men and women.
As with so much good science, this discovery, published in the journal Cell Reports, was an unexpected offshoot of a much bigger body of research. A team at Dr. Carmit Levy’s lab at Tel Aviv University was studying the cancerous effects of skin exposure to UVB light — one of the three wavelengths present in sunlight — when they discovered a heap of proteins related to sexual behavior hiding among skin cells. Roma Parikh, a PhD student in the lab, found initial evidence of UV exposure’s effects on testosterone levels in a paper from 1939, but couldn’t find any more research that had come after that. “And we really wanted to continue,” she says.
The new research adds to these eighty-year-old findings by confirming the existence of a similar effect in females. It also identifies the first player in the chain of biological processes that causes the phenomenon, a DNA-repair protein in the skin known as p53. Though it’s unknown yet whether p53 stimulates the release of fun and flirty hormones by communicating directly with the body’s hormone storage centers or if it has to send messages to the brain first, identifying this protein confirms that a sun-to-hormones mechanism exists.
To prove the effect for both sexes, Parikh observed mice after exposing them to low-intensity UVB. The animals were all over each other. When her team measured the levels of sexual hormones in the mice, they came back much higher than before their sunbath for males and females, with the females sent into heat.
When the team recreated the experiment with a small group of 19 humans, Parikh found evidence of the same hormonal trends. A questionnaire given to the group also showed higher passion across the board after time in the sun. The authors reported that women scored higher on questions about physical arousal, while men scored higher in the “cognitive dimension of passion,” including feeling a deep desire to get to know their partner better.
So, does this mean that sunbathing is the new foreplay? Yes! But don’t skip the sunscreen. Although sunshine might make you horny, it can also still give you skin cancer, which is decidedly unsexy. The hormonal boost happens quickly, after just 15 to 20 minutes of sunlight, but sunburn can happen even faster than that. Thankfully, Parikh promises that sunscreen won’t block any of the arousing benefits of a midday stroll with your partner.
This sun-passion connection calls to mind a whole host of earlier findings that could be tied to the phenomenon. Could it be one of the reasons why so many studies seem to find that people have more sex during the summer months? Aside from being able to see your partner, might sunlight add a little something extra to the hormonal alignment that seems to favor afternoon sex?
Parikh is hopeful that, looking forward, her research could lead to a possible future of UV treatments as hormonal therapy. “With infertility going up and young people having less sex, I think it could be really amazing,” she says.
Developments like that could be pretty far down the road, and there’s still so much that researchers have to learn about the exact mechanisms and limits of sunlight’s effects on human hormones. Until then, at least we’ve got a new meaning to “fun in the sun.”
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