Before you head into a dengue, zika or malaria zone: the % on the bottle isn't a strength rating — it's a clock. Pick your repellent below and we'll estimate your protection window against mosquitoes (and ticks), then schedule your re-applications for the day.
No repellent gives you a guaranteed number of hours. Tropical heat, humidity, sweat and a swim in the sea all eat into it, which is why we quote a range instead of a single figure. The numbers lean on EPA repellent guidance, CDC travel-health notices, the National Pesticide Information Center, and the well-known Fradin & Day field study.
A bigger number means more hours, not a stronger shield — and it tops out. DEET stops improving around 50%, so our estimates level off there rather than climbing without limit.
Dengue and zika come from day-biting Aedes mosquitoes; malaria from night-biting Anopheles. Coverage duration matters most when you're exposed all day — reapply on schedule and treat clothing for the night.
It bonds to fabric and kills mosquitoes on contact, so we report its lifespan in laundry cycles: ~5–6 washes for DIY sprays, up to ~70 for factory-treated gear. Treat your wardrobe before you fly — never your skin.
A "5–8 hour" window is honest about how much conditions vary. Plan around the low end and top up before you reach it — sweat and tropical heat burn through it faster than you'd think.
| Active ingredient | Concentration | Mosquitoes | Ticks | Notes |
|---|---|---|---|---|
| Picaridin | ~10% | ~5–8 hrs | ~3–5 hrs | Great for a half-day |
| Picaridin | ~20% | ~8–12 hrs | ~8–12 hrs | Travel-clinic favorite; gear-safe |
| DEET | ~10% | ~2–3 hrs | ~2–3 hrs | Travel minis |
| DEET | ~20–25% | ~4–6 hrs | ~3–5 hrs | Standard everyday strength |
| DEET | ~30% | ~5–8 hrs | ~4–6 hrs | Slow-release formulas hit the high figure |
| DEET | ~50%+ | ~6–8 hrs | ~6–8 hrs | Tops out — no benefit past 50% |
| Oil of Lemon Eucalyptus (PMD) | ~30% | ~4–6 hrs | ~4–6 hrs | Off-limits for under-3s |
| IR3535 | ~10–20% | ~4–6 hrs | ~4–6 hrs | Depends heavily on the brand |
| Permethrin (clothing) | 0.5% spray | Kills mosquitoes on contact · holds up ~5–6 washes (DIY) to ~70 washes (factory-treated) | Fabric only; let it dry away from cats | |
Treat these as planning figures, not guarantees — and not medical advice. For malaria prevention, vaccines, and destination-specific risk, see a travel medicine clinic before you go.
Picaridin at 20% protects for roughly 8–12 hours — a full day of sightseeing — while 10% formulas last about 5–8 hours. It's the concentration most travel clinics recommend for dengue and zika zones: odorless, dry to the touch, and safe on sunglasses and synthetic gear.
Re-apply when your window runs out, and always after swimming, sweating, or toweling off. 20% picaridin and 30% DEET cover most of a day; 10% travel minis fade in a few hours; plant-based sprays need topping up every 4–6 hours. Enter your day length above for an exact schedule.
Yes — the CDC advises pregnant travelers to Zika-risk areas to use an EPA-registered repellent, and both DEET and picaridin are considered safe when used as directed. Apply it over sunscreen, cover exposed skin, and see a travel medicine clinic before you go.
A DIY permethrin spray lasts about 6 weeks or 5–6 washes; factory-treated garments last around 70 washes. Treat your wardrobe at home ~48 hours before departure. It repels and kills mosquitoes on contact with the fabric — clothing only, never skin, and keep it from cats until dry. Staying stateside instead? Our sister site TickWise runs the same numbers for tick country.