No-See-Um Repellent: How to Pick One That Actually Lists Them
The CDC's advice for no-see-ums is specific: use an EPA-registered repellent whose label lists flies, biting flies, or Culicoides. Most repellent labels only state mosquito and tick claims, so check the label itself. Of 631 EPA-registered skin repellents, 47 carry a stated no-see-um protection time.
Most repellent shopping advice is written for mosquitoes. No-see-ums, the biting midges that ruin beach evenings and lakeside porches, are a different insect with their own line on a repellent label, and most products never mention them. This is how to pick one that does, and what to do alongside it, using only what the CDC, EPA, and state health departments actually say.
What does the CDC say to look for?
One sentence does most of the work. The CDC, writing about preventing bites from the midges that spread Oropouche virus, says: "Look for EPA-registered repellents labeled for flies, biting flies, or Culicoides (biting midges, punkies, granny nippers, and no-see-ums)." Culicoides is the genus of biting midge, and it is the word a label uses when the manufacturer has registered a claim against them.
The same guidance carries the reassurance that matters when you are comparing bottles: "When used as directed, EPA-registered insect repellents are proven safe and effective." Registration is the floor. The label text is where products differ.
There is also a reason beyond comfort to take midges seriously. Biting midges are the primary spreaders of Oropouche virus, and the CDC states plainly that there are no vaccines to prevent it and no medicines to treat it: “The best way to protect yourself from Oropouche is to prevent bug bites.” For this insect, prevention is not one option on a menu. It is the menu.
Why isn't "repels mosquitoes" enough?
Because a repellent label is a registered document, and claims on it are pest by pest. A product registered for mosquitoes and ticks has told EPA nothing about biting midges. Even EPA's own consumer search tool reflects this: it lets you filter by mosquitoes, ticks or both, protection time, and active ingredient, and midges are not one of the filters. EPA's standing instruction covers the gap: "always read the product label before using the product." For no-see-ums, the label is the only place the answer lives.
Because EPA's tool cannot answer the midge question, we built something that can. The Repellent Index holds every EPA-registered skin-applied repellent, 631 products, with the pest claims we could read off each product's federal label. Of those 631, 47 carry a stated no-see-um protection time. The full statistics are free, and so is the dataset.
Which active ingredients are recommended?
For biting flies as a group, the Illinois Department of Public Health names two: repellents "containing the active ingredient DEET (N,N-diethyl-meta-toluamide) or picaridin are best." On picaridin specifically, the National Pesticide Information Center notes it "can be used on human skin or clothing to repel mosquitoes, biting flies, ticks, fleas, and chiggers," and that it is a synthetic compound made to resemble piperine, found in the group of plants used to produce black pepper.
Illinois DPH also says the honest thing most marketing leaves out: repellents, while effective against mosquitoes, "have been found to be less effective against some types of biting flies," and should be supplemented with other preventive methods, like avoiding the areas the flies inhabit and their peak biting times. A repellent with a midge claim on its label is the right tool. It is still one tool.
How do you apply repellent so it actually works?
EPA's application rules, from its guidance on using repellents safely and effectively:
- Read and follow the label directions, and be sure you understand how much to apply.
- Apply only to exposed skin and/or clothing. Do not use under clothing.
- Keep it away from eyes and mouth, apply sparingly around ears, and with sprays, apply to hands first and then to the face.
- Never apply over cuts, wounds, or irritated skin.
- For children: do not apply to children's hands. Apply to your own hands first, then put it on the child.
- Afterward: wash treated skin and clothes with soap and water once you are back indoors.
What works alongside repellent?
Three things, all from the CDC's midge guidance:
- Clothing. Wear loose-fitting, long-sleeved shirts and pants.
- Better screens. Many common window and door screens do not have holes small enough to stop biting midges. The CDC's recommendation is 20x20 mesh.
- A fan. The CDC suggests using fans outdoors to help blow biting midges away. Illinois DPH agrees: fans can keep small areas free of the smaller flies, whose flight is affected by air currents.
Timing is harder to game than it is for mosquitoes. A CDC entomologist notes there is no single biting hour: biting midges can be out at different times of day, and the time varies among species. And if you are hoping the county will handle it, the CDC is frank that less is known about controlling biting midges in the community than about controlling mosquitoes. The tools you control, label-checked repellent, clothing, screens, and moving air, are most of the game.
Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients.
Short answers
What is the best repellent for no-see-ums?
The CDC does not rank products. Its guidance is to use an EPA-registered repellent whose label lists flies, biting flies, or Culicoides. Illinois DPH points to DEET and picaridin as the actives to look for against biting flies. From there, compare the labels: 47 of the 631 registered skin repellents state a no-see-um protection time.
Does DEET work on no-see-ums?
Illinois DPH names DEET, along with picaridin, as the actives to look for against biting flies, while cautioning that repellents can be less effective against some biting flies than against mosquitoes. Check the individual product label for a midge or biting-fly claim.
Why do no-see-ums get through my window screens?
Standard mesh is too coarse. The CDC says many commonly used window and door screens do not have holes small enough to stop biting midges, and recommends 20x20 mesh screens.
Do fans really keep no-see-ums away?
The CDC recommends using fans outdoors to help blow biting midges away, and Illinois DPH notes fans can keep small areas free of smaller flies because their flight is affected by air currents. Weak fliers, moving air. It is the cheapest tool on this page.
What time of day do no-see-ums bite?
There is no single answer. Per a CDC entomologist, biting midges can be active at different times of day, and the timing varies among species. Assume any calm hour near water can be a biting hour.
Sources
- CDC, Preventing Oropouche. https://www.cdc.gov/oropouche/prevention/index.html
- CDC, Oropouche Puts Biting Midges Under the Microscope. https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html
- EPA, Find the Repellent that is Right for You. https://www.epa.gov/insect-repellents/find-repellent-right-you
- EPA, Using Insect Repellents Safely and Effectively. https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively
- NPIC, Picaridin General Fact Sheet. https://npic.orst.edu/factsheets/PicaridinGen.html
- Illinois Department of Public Health, Biting Flies. https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html
Last reviewed 2026-08-26 · every claim on this page is sourced above