Mosquito repellent is one of the most tested categories in consumer pest control, and the research is fairly clear on what works. The confusion mostly comes from marketing language and from confusing personal protection with yard control. Here is what the science actually says about the main active ingredients and how to use them correctly.
Quick answer
EPA-registered repellents containing DEET, picaridin, IR3535, or oil of lemon eucalyptus (OLE) do work at keeping mosquitoes from landing on treated skin. The protection time depends on the concentration and product. What repellent cannot do is reduce the mosquito population in your yard. You are still surrounded by the same number of mosquitoes; you are just harder for them to land on. For a yard with a real mosquito problem, repellent is a personal shield, not a solution.
Want this handled for you?
Personal repellent protects you. Barrier treatment protects your yard. Schedule a mosquito treatment with Mosquito Guard Pro and reduce the number you are dealing with in the first place.
How Repellents Work
Mosquitoes find hosts through a combination of carbon dioxide, body heat, and skin odor compounds. Most effective repellents do not work by creating a smell mosquitoes hate. They work by interfering with the receptors mosquitoes use to detect those attraction signals, making treated skin effectively invisible as a landing target.
This distinction matters because it explains the limits of repellent. The mosquitoes are still there, still flying, still looking. You are just harder for them to detect. The moment the repellent wears off, or you miss a patch of skin, the full attraction signal returns.
DEET
DEET (N,N-Diethyl-meta-toluamide) has been registered with the EPA since 1957 and is the most extensively tested mosquito repellent active ingredient available. Higher concentrations provide longer protection time, not stronger protection. A product with 25 to 30 percent DEET provides about five hours of protection. A product with 10 percent provides about two hours.
DEET is effective against a wide range of biting insects and ticks, not just mosquitoes. It is safe for use on adults and children over two months old according to the EPA and CDC, though it should not be applied to hands, around eyes, or over cuts. It can damage plastics and synthetic fabrics, which is worth knowing before you spray it near gear.
Picaridin
Picaridin is the most commonly recommended alternative to DEET. A 20 percent picaridin product provides roughly eight hours of protection against mosquitoes, comparable to a mid-to-high concentration DEET product. It does not damage plastics or synthetics, has no noticeable odor, and most people find the feel on skin more comfortable than DEET.
The CDC lists picaridin as an effective repellent alongside DEET. For people who dislike the DEET experience, picaridin at 20 percent is a genuine equivalent, not a compromise.
Oil of Lemon Eucalyptus and IR3535
Oil of lemon eucalyptus (OLE) is a plant-derived active ingredient with solid EPA data behind it. Products with OLE at 30 percent provide about six hours of protection and are the only plant-based repellent the CDC lists alongside DEET and picaridin for tick prevention as well as mosquitoes. Note that OLE is not the same as lemon eucalyptus essential oil; the distinction matters because the essential oil has no meaningful registered efficacy data.
IR3535 is another EPA-registered option found in some sunscreen-repellent combination products. It provides moderate protection and is safe for children but tends to provide shorter protection windows than DEET or picaridin at equivalent concentrations.
What Repellent Cannot Do
Repellent protects the person wearing it. It does not reduce the mosquito population in your yard, clear standing water where larvae develop, or treat the resting spots where adults hide. In a yard with active breeding sources and high adult pressure, you can still be surrounded by hundreds of mosquitoes while wearing repellent. You just will not be bitten as much.
For events, camping, or short outdoor activities, repellent is practical and effective. For living comfortably in your own backyard through a San Antonio summer, it is one piece of the picture. Barrier treatment of the yard handles the population; repellent handles the gaps.