Hair Barrier

Short answer: The best-known experiment on this idea didn't use mosquitoes. In 2011, Isabelle Dean and Michael Siva-Jothy at the University of Sheffield published a study in Biology Letters using 29 volunteers, each with one arm shaved and one unshaved.

They released bed bugs (Cimex lectularius) onto each arm. On unshaved arms, the bugs took longer to find a place to feed, and volunteers noticed them more often. People with more hair were better at detecting the bugs. The authors suggested that fine body hair may persist partly because it helps people sense parasites. Mosquitoes are different, because they fly in and land rather than crawl across the skin. They find people mainly through exhaled carbon dioxide, body heat and skin odor; a 2022 study in Cell linked 'mosquito magnet' status to higher levels of carboxylic acids on the skin. A 1976 laboratory study of Anopheles gambiae landings on volunteers' forearms found that forearm hair density, along with skin temperature, humidity and color, explained very little of the variation in which person mosquitoes chose. So the idea that hair helps you feel a crawling insect has experimental support, but only for bed bugs. That it makes mosquitoes land less or bite less hasn't been shown. The footage shows a mosquito walking through dense arm hair.