Most mosquito repellents on the market are the same 4–5 active ingredients in different packaging and concentrations. Understanding what each active ingredient does — and what it doesn't do — is more valuable than any brand name. CDC currently recommends DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), and 2-undecanone as effective mosquito repellents.
Best Mosquito Repellents — Ranked by Effectiveness
Permethrin is not a repellent — it is a contact insecticide applied to clothing and gear that kills mosquitoes and ticks on contact. It is the single most effective mosquito and tick protection tool available, and the U.S. military issues permethrin-treated uniforms to troops in vector-endemic zones. A tick that contacts permethrin-treated fabric experiences knockdown in 10–20 seconds and dies within minutes.
Critical rule: Never apply permethrin directly to skin — apply only to clothing, footwear, socks, hats, and gear. It binds to fabric fibers and remains effective through 6 washings when applied correctly (hang dry after washing to preserve treated fibers).
The combination strategy: Permethrin on clothing + DEET 20–30% on skin = the maximum available protection against both mosquitoes and ticks. This is what the CDC recommends for travel to malaria, dengue, or Zika risk areas.
Picaridin (also called icaridin, Bayrepel) has displaced DEET as the preferred skin-applied repellent in Europe and Australia, and is increasingly preferred in the U.S. by those who dislike DEET's feel and smell. At 20% concentration, picaridin provides 8–14 hours of mosquito protection and 8+ hours of tick protection — equivalent to DEET 25–30%.
Advantages over DEET: No damage to plastics, synthetic fabrics, or finishes (DEET dissolves watch crystals, fishing line, and synthetic fabric). Odorless (to humans). Less greasy feel. Considered safer for children over 2 months of age. Does not absorb through skin as readily as DEET.
CDC-recommended as a full equivalent to DEET for disease prevention. Effective against Aedes aegypti and Aedes albopictus mosquitoes (Zika, dengue, chikungunya vectors).
DEET (N,N-diethyl-meta-toluamide) has been the gold standard insect repellent since 1946 — and remains the most extensively tested repellent in existence. At 98%, Repel 100 provides up to 10 hours of mosquito protection and is appropriate for extreme exposure situations (backcountry, high-density mosquito environments, travel to high-risk disease areas). For most everyday outdoor use, 20–30% DEET is equivalent in protection with fewer skin absorption concerns.
DEET safety: DEET is safe as directed — decades of research and billions of applications have not demonstrated systemic toxicity at recommended application rates. The EPA completed a comprehensive re-evaluation in 1998 and concluded DEET poses no health concerns. Do not apply to children under 2 months. Do not apply under clothing.
Oil of lemon eucalyptus (OLE) and its refined form para-menthane-diol (PMD) are the only plant-derived repellents CDC-approved for mosquito-borne disease prevention. PMD-based products provide 6+ hours of protection at 30% concentration — comparable to DEET 20% in duration. Important distinction: OLE (from lemon eucalyptus) is not the same as straight lemon eucalyptus essential oil, which has not been demonstrated effective.
Not for children under 3 years old — this is a CDC restriction specific to OLE, even though it is plant-based. Picaridin is the better choice for families with young children.
Active Ingredient Quick Guide
| Active Ingredient | Max Duration | Tick Protection | Kids Safe | Damages Plastic | Application |
|---|---|---|---|---|---|
| Permethrin 0.5% | 6 washes | Kills on contact | Yes (on clothing) | No | Clothing only — never skin |
| Picaridin 20% | 8–14 hours | Yes | 2 months+ | No | Skin and clothing |
| DEET 30% | 6–8 hours | Yes | 2 months+ | Yes | Skin (avoid synthetic fabrics) |
| DEET 98% | 10+ hours | Yes | Adults only | Yes | Skin (extreme use) |
| OLE/PMD 30% | 6+ hours | Limited | 3 years+ | No | Skin and clothing |
| IR3535 20% | 4–8 hours | Limited | Yes | Damages some plastics | Skin |
For high-risk environments (Lyme disease territory, mosquito-borne disease travel, dense tick habitat): Permethrin on all clothing + Picaridin 20% on all exposed skin. This combination is used by U.S. military deployed in vector-endemic regions and provides the highest level of commercially available protection. Neither product alone matches the combination.