DEET, Picaridin, or Citronella? The Truth About Insect Repellents for Travelers

Mosquitoes Kill More People Than Any Other Animal on Earth

It's not sharks. It's not snakes. Mosquitoes are the deadliest animal on the planet, responsible for transmitting diseases that kill hundreds of thousands of people every year. For travelers, the list of mosquito-borne threats is staggering: malaria, dengue, Zika, chikungunya, Japanese encephalitis, yellow fever, and more.

But mosquitoes aren't the only concern. Ticks transmit Lyme disease, tickborne encephalitis, and Rocky Mountain spotted fever. Sandflies carry leishmaniasis. Tsetse flies transmit sleeping sickness. For travelers to tropical and subtropical destinations, insect bite prevention isn't a minor detail — it's a critical layer of health protection alongside vaccines and medications.

Unfortunately, the insect repellent market is full of products that don't work, and many travelers make choices based on marketing rather than science. Let's sort fact from fiction.

What Actually Attracts Mosquitoes to You

Understanding what draws mosquitoes helps explain why some people seem to get bitten more than others:

• Carbon dioxide — from your breath and skin, detectable by mosquitoes from up to 36 metres away
• Body heat and sweat — lactic acid, moisture, and warmth on your skin are powerful close-range attractants
• Skin bacteria — the microbiome on your skin produces volatile compounds that vary between individuals
• Dark clothing — daytime-biting mosquitoes orient visually toward dark colours and movement
• Fragrances — perfumes, scented lotions, and floral-scented soaps can attract biting insects
• Body size — larger individuals produce more CO2 and heat, attracting more mosquitoes. Men tend to be bitten more than women, and adults more than children.

This means some people genuinely are more attractive to mosquitoes than others — it's not imagination. But no one is immune, and a single bite from an infected mosquito is all it takes to transmit malaria or dengue.

The Proven Repellents: What Science Backs Up

DEET: Still the Gold Standard After 60+ Years

DEET (N,N-diethyl-meta-toluamide) has been used by the general public since 1957, and over 200 million people worldwide use it annually. Despite decades of scrutiny, it remains the benchmark against which all other repellents are measured.

What it protects against: Mosquitoes, biting flies, midges, chiggers, fleas, and ticks — the broadest spectrum of any repellent available.

How to choose a concentration:

• 10% to 30% DEET is adequate for most travel situations
• Higher concentrations provide longer-lasting protection, not stronger protection — 30% DEET lasts longer than 10%, but doesn't repel more effectively at any given moment
• In Canada, Health Canada has capped DEET products at 30% maximum concentration
• Extended-release formulations (like 35% Ultrathon, developed for the US military) can provide up to 12 hours of protection

Is DEET safe? Yes. This is one of the most persistent myths in travel health. After 50+ years of use by hundreds of millions of people:

• Fewer than 50 cases of significant toxicity have ever been reported — most involving misuse or excessive application
• The US EPA, Health Canada, and CDC all confirm DEET is safe for anyone over 2 months of age
• Safe in pregnancy — a controlled study of 450 pregnant women using DEET daily showed no adverse effects on mothers or babies. The CDC recommends DEET for pregnant and breastfeeding women.
• Children over 2 months can safely use up to 30% DEET (American Academy of Pediatrics recommendation)

Practical tips:

• Apply to exposed skin and clothing — but not under clothing
• Don't apply to cuts, wounds, or irritated skin
• Avoid eyes and mouth
• DEET can damage plastics (watch faces, sunglasses, some synthetic fabrics like rayon and spandex) — keep it away from these
• DEET reduces sunscreen effectiveness by about 33%. Apply sunscreen first, then repellent on top. Avoid combination sunscreen/repellent products.

Picaridin: The Modern Alternative

Picaridin (also called icaridin) has been available in Europe since 1998 and in North America since 2005. At 20% concentration, studies show it provides protection comparable to DEET against mosquitoes, biting flies, and ticks.

Advantages over DEET:

• Nearly odourless and feels pleasant on the skin — no greasy residue
• Does not damage plastics, fabrics, or finishes
• Does not reduce sunscreen effectiveness
• Excellent safety profile with no significant toxicity concerns

The CDC has approved 20% picaridin as an effective option for preventing mosquito-borne diseases. Products like Natrapel (20% picaridin) are widely available in Canada. If you dislike the feel or smell of DEET, picaridin is a legitimate, science-backed alternative.

Oil of Lemon Eucalyptus (PMD)

Oil of lemon eucalyptus (the refined extract p-menthane-3,8-diol, or PMD) is the only plant-derived repellent endorsed by the CDC. At 30% concentration, it provides reasonable protection against mosquitoes, though typically for shorter duration than DEET or picaridin. It should not be used on children under 3 years old.

Important: this is the refined chemical extract (PMD), not raw lemon eucalyptus essential oil — the two are not the same product and have very different effectiveness.

IR3535

IR3535 (ethyl butylacetylaminopropionate) is another CDC-approved repellent with a strong safety profile. It's effective against mosquitoes and ticks, non-greasy, nearly odourless, and won't damage plastics. It's found in some Avon Skin-So-Soft products. Protection times vary widely by formulation, so check the concentration.

What Doesn't Work: Save Your Money

The market is flooded with "natural" and "alternative" insect repellent products. Here's what the research actually shows:

Citronella

The most popular "natural" repellent ingredient, citronella evaporates rapidly from the skin, providing protection for under 2 hours at best. The EPA requires citronella-based products to state that they need to be reapplied every hour. In high-risk disease environments, this is not reliable protection.

Citronella candles? A study found they reduced mosquito bites by 42% — but plain, unscented candles reduced bites by 23%, mostly just from the heat and CO2 of the flame. The citronella itself added marginal benefit.

Proven Ineffective

• Repellent wristbands — do not create a protective zone around your body. Untreated skin is readily bitten.
• Electronic ultrasonic repellers — multiple studies confirm they do not repel mosquitoes
• Garlic consumption — no evidence of repellent effect
• Vitamin B1 (thiamine) — no evidence of repellent effect
• Citronella plants in the garden — the plant itself does not repel mosquitoes

In an environment where a single mosquito bite could transmit malaria or dengue, relying on unproven products is a genuine health risk.

Permethrin-Treated Clothing: Your Second Layer of Defence

While repellents protect exposed skin, permethrin-treated clothing protects the skin underneath your clothes — and it's remarkably effective.

Permethrin is a contact insecticide (not a repellent) that kills mosquitoes, ticks, and other insects on contact with treated fabric. Key facts:

• Spray it on shirts, pants, socks, hats, and shoes before your trip — let dry completely before wearing
• A single treatment lasts through several weeks of wear and multiple washes
• Factory-treated clothing (like Insect Shield brand) maintains effectiveness for up to 70 washes
• Permethrin is not applied to skin — only to fabric, gear, bed nets, and mesh shelters
• Safe for pregnant women when used on clothing

The combination of DEET or picaridin on exposed skin + permethrin-treated clothing is the most effective personal protection strategy available. Military forces worldwide use this approach.

Bed Nets: Essential for Malaria Areas

The malaria-transmitting Anopheles mosquito bites primarily between dusk and dawn. In malaria-endemic areas, sleeping under an insecticide-treated bed net (ITN) is one of the most effective prevention measures available.

• Choose a net treated with permethrin — or buy a long-lasting insecticidal net (LLIN) that comes pre-treated
• Tuck the net under your mattress on all sides, ensuring no gaps
• Check for holes or tears before use
• Even if your hotel has screens and air conditioning, a bed net adds an additional layer of protection in high-risk areas

Putting It All Together: A Practical Bite Prevention Plan

1. Clothing: Wear long sleeves and pants, especially at dawn and dusk. Choose light colours. Treat clothing with permethrin before your trip.
2. Repellent: Apply 20-30% DEET or 20% picaridin to all exposed skin. Reapply as directed (typically every 4-8 hours depending on formulation and conditions).
3. Accommodation: Choose rooms with screens or air conditioning when possible. Sleep under a treated bed net in malaria areas.
4. Timing: Limit outdoor exposure at peak biting times — dusk to dawn for malaria mosquitoes, daytime for dengue and Zika mosquitoes.
5. Avoid attractants: Skip perfumes and scented products. Use unscented soap and deodorant.

When to See a Travel Health Professional

Insect bite prevention is just one part of a comprehensive travel health plan. A travel health physician can:

• Assess which insect-borne diseases are present at your specific destination
• Determine whether you need antimalarial medication in addition to bite prevention
• Recommend vaccines for mosquito-borne diseases like yellow fever and Japanese encephalitis
• Advise on the right repellent products for your trip duration, climate, and activities
• Provide guidance for pregnant women and young children

At Virtual Travel Clinic, our physicians build a complete protection plan during your virtual consultation — covering vaccines, medications, and bite prevention tailored to your destination. All prescriptions and recommended products are available at our pharmacy.

The best insect bite is the one that never happens. Book your consultation and travel protected.