Study summary
Comparative Efficacy of Insect Repellents against Mosquito Bites
Fradin MS, Day JF
Read the original paper- Study type
- Rct
- Year
- 2002
- Published in
- New England Journal of Medicine (2002), 347(1):13-18
- Evidence strength
- Definitive evidence
Summary
This widely cited New England Journal of Medicine study compared many different mosquito repellents head to head to see how long each one actually kept mosquitoes from biting. Volunteers put their treated arms into a cage of hungry mosquitoes, and the researchers recorded the time until the first bite for each product. Alongside skin-applied repellents such as DEET at various concentrations, the study included repellent-impregnated wristbands, which is the format sold as a hands-off, wear-it-and-forget-it alternative to putting repellent on your skin.
Key findings
The skin-applied DEET products provided the longest protection, with higher concentrations lasting several hours before the first bite. The repellent-impregnated wristbands, by contrast, offered essentially no protection, with volunteers bitten almost immediately whether the band contained a repellent chemical or a plant oil. The lesson for a buyer is direct and format-based: repellent that surrounds and clings to your skin works, while the same or similar repellent confined to a band on the wrist does not stop bites on the rest of the body.
Limitations
This was a controlled cage assay measuring time to first bite on a treated arm, which is a rigorous way to rank repellents but is not the same as a full evening in a backyard. The wristbands tested were the versions available at the time, and the finding is about the band format rather than a claim that the oils themselves are inert in every use. The result nonetheless lines up with later work: a scented band cannot protect skin it does not reach.