If you've been noticing larger clumps of hair stuck to your comb when you get out of the shower over the past few months, don't freak out. It's actually common for people to lose more hair in the summer and fall than in the winter and spring, according to a study in the British Journal of Dermatology.
The researchers analyzed search data on Google Trends from eight countries between 2004 and 2016 to determine when people were typing in "hair loss." The most hair loss-related searches were in the summer and fall, then winter, then spring. Supporting these results, one 1991 study in the British Journal of Dermatology that measured 14 men's hair follicles found that they lost the most in August and September.
The new study's co-author Dr. Shawn Kwatra, a dermatology resident at Johns Hopkins Hospital, told Medical News Today that the data matched his experience with patients. "What is also interesting is that seasonal variations in hair loss also occurs in animals and has been noted in studies with rhesus monkeys, cats, and dogs. In particular, seasonal flank alopecia has been described in dogs," he said.
One might expect that we'd lose the most hair in the spring and summer, when we need it the least for warmth. The authors aren't sure why they instead found the pattern they found. However, one possibility is that we lose more hair when the days get shorter because we don't need it as much to protect us from the sun, according to Medical Daily. Another is that ultraviolet rays influence our hair loss.
Along with seasonal changes, losing more hair than usual can result from a major change your body's undergoing, like recent childbirth, weight loss, or going on or off birth control. However, it's normal to lose between 100 and 150 hairs each day, so it's not generally anything to worry about.