Concentration doesn't tell you how strong a repellent is — it tells you how long it lasts. Pick your product below and we'll estimate your protection window against ticks and mosquitoes, then build a re-apply schedule for your day outside.
Protection time isn't a single number. It shifts with heat, sweat, swimming, and how much you apply, so every estimate here is a range, not a promise. Our figures are built from the EPA's repellent guidance, CDC prevention data, the National Pesticide Information Center, and the landmark Fradin & Day duration study — cross-checked against our own field testing in Connecticut.
More active ingredient buys more hours of protection — up to a ceiling. DEET plateaus around 50%; beyond that you gain almost nothing. That's why we cap the estimates instead of scaling them forever.
Most published durations come from mosquito studies; solid tick-specific numbers are thinner. Where the data is weaker for ticks, we lean conservative and flag it — for ticks, 20% picaridin plus permethrin-treated clothing is the best-supported combination.
It bonds to fabric and kills ticks on contact, so we report its lifespan in laundry cycles: about 6 washes for DIY sprays, up to ~70 for factory-treated gear. It's never applied to skin.
A "4–5 hour" answer reflects real-world variation. If anything, treat the low end as your planning number and re-apply before you hit it — especially on hot, sweaty days.
| Active ingredient | Concentration | Mosquitoes | Ticks | Notes |
|---|---|---|---|---|
| DEET | ~5–7% | ~1.5–2 hrs | ~1.5–2 hrs | Quick errands only |
| DEET | ~10% | ~2–3 hrs | ~2–3 hrs | Short outings |
| DEET | ~20–25% | ~4–6 hrs | ~3–5 hrs | CDC everyday range |
| DEET | ~30% | ~5–8 hrs | ~4–6 hrs | Controlled-release reaches the top end |
| DEET | ~50%+ | ~6–8 hrs | ~6–8 hrs | Plateau — no gain above ~50% |
| Picaridin | ~10% | ~5–8 hrs | ~3–5 hrs | Step up to 20% for ticks |
| Picaridin | ~20% | ~8–12 hrs | ~8–12 hrs | Full trail day, gear-safe |
| Oil of Lemon Eucalyptus (PMD) | ~30% | ~4–6 hrs | ~4–6 hrs | Not for children under 3 |
| IR3535 | ~10–20% | ~4–6 hrs | ~4–6 hrs | Varies by product formulation |
| Permethrin (clothing) | 0.5% spray | Kills & repels on contact · lasts ~6 washes (DIY) to ~70 washes (factory-treated) | Never on skin; keep from cats until dry | |
Ranges are directional estimates for planning, not guarantees, and are not medical advice. Manufacturer label claims often run higher than independent field results; we lean toward the conservative end. For tick-borne illness concerns, talk to a doctor.
Not stronger — longer. A higher concentration of DEET mainly extends how many hours you're protected, not how well it repels in the first place. The effect plateaus around 50%: above that, extra DEET adds essentially no additional protection time, which is why the CDC and EPA don't push the highest concentrations for everyday use.
Re-apply when your protection window runs out — or sooner if you've been sweating heavily, swimming, or toweling off. 20% picaridin and 30%+ DEET last most of a day; 10% formulas fade in 2–5 hours; oil of lemon eucalyptus needs topping up every 4–6 hours. Enter your trip length above and we'll lay out the schedule.
A DIY permethrin spray like Sawyer lasts about 6 weeks or 6 washes; factory-treated garments (e.g. Insect Shield) last roughly 70 washes — effectively the life of the garment. It kills and repels ticks on contact with the treated fabric, which is why the CDC recommends it for tick country. Apply it to gear, never skin, and keep it away from cats until fully dry.
Both work. Picaridin at 20% protects for a full trail day, is odorless, feels dry, and won't harm plastics or synthetic gear the way DEET can — it's our best overall pick. DEET at 20–30% is also effective. For the strongest defense, layer either skin repellent over permethrin-treated clothing.