 Mosquitoes are not just a nuisance, but the carriers of disease, like Zika dengue fever. Deet has been the go-to repellent for decades now. So what does research say about its safety and effectiveness? And are there better natural alternatives? I'll answer these questions in this video and the next. The most dangerous animal in the world isn't the great white or the king cobra or lions and tigers and bears. In fact, only about 10 people die in shark attacks every year. Coming in number two is most dangerous, fellow human beings. But the worst? Mosquitoes. Literally billions of people are at risk of contracting dengue fever for mosquitoes and hundreds of thousands die from mosquito-borne malaria every year. New threats like Zika continue to pose a global public health threat, such as the World Health Organization suggested delaying pregnancy in Zika-affected areas around the world. What's the best mosquito repellent to wear? There are products like permethrin, a product originally derived from chrysanthemums, interestingly, that can be applied to clothes. But what about repellents you actually put on your skin? Deet is the repellent to beat, considered the gold standard of protection when it's crucial not to get bitten. It was developed back in the 1940s for use by the military. It's long been considered the first line mosquito repellent, affecting this wise, 20 to 50% deet repellents provide up to several hours of protection. That's rubbed on the skin, though. Deet impregnated wrist bands don't work, repelling mosquitoes only from areas covered by the band, which I guess you could say about non-deet impregnated wrist bands. Deet or citronella wrist bands have been clocked at working more broadly for only 12 to 18 seconds. Safety-wise, deet is considered safe, even in the second and third trimesters of pregnancy and in children, as long as they're older than two months. Now, it should be noted that deet can damage plastics and synthetic materials. Therefore, care should be taken when it's used around plastic watches, eyeglasses, and synthetic fabrics. Nylon is okay, but it's been found to damage spandex, rayon, acetate, and pigmented leather, in addition to plastic and vinyl. Deet is absorbed through your skin into your bloodstream, but it's cleared from your system within a few hours. Does it have any adverse effects? Deet is probably far less toxic than many people believe. Deet has a remarkable safety profile, after now more than a half century of use and billions of applications. Fewer than 50 cases of serious toxic effects have been documented in the medical literature since 1960, and most of them resolved. Most reported cases of adverse or lethal events involve overuse or incorrect use of the product, incorrect use as in chugging it to commit suicide. What's a correct usage? Read and follow all directions on the product label. Only apply to intact, non-irritated skin. Do not apply near eyes and mouth and only sparingly around ears. That's to avoid accidental eye exposure or ingestion. It can be applied to the face, but don't spray it in your face. Spray it on your hands, and then you can dab on, but still avoid the eyes and mouth. Apply it to children so they don't swallow any. G.C.s use enough to cover exposed skin or on the outside of clothing, not underneath. And then once you're back inside, wash it off with soap and water and wash any treated clothing. If you do have a reaction, stop using it, wash it off, call your local Poison Control Center, and if you go to your doctor, bring the bottle. So, which mosquito repellent works best? Well, an head-to-head test deep crushed it, but this was in reference to a study published about 20 years ago. Anything new on the market that won't melt your eyeglasses? We'll find out next.