DEET vs Picaridin: Which Repellent Is Right for You?

When shopping for mosquito repellent in Australia, you'll encounter two dominant active ingredients: DEET and Picaridin. Both are proven effective against mosquitoes, yet they differ significantly in their feel, application, and suitability for different situations. This comprehensive guide examines both ingredients through a scientific lens, helping you make an informed choice for your specific needs.

Understanding DEET

DEET (N,N-Diethyl-meta-toluamide) has been the gold standard in mosquito repellents since its development by the U.S. Army in 1946. Originally created for military personnel in insect-heavy combat zones, it entered civilian markets in 1957 and has since accumulated more research data than any other repellent ingredient.

How DEET Works

For decades, scientists believed DEET worked by masking human scent from mosquitoes. However, more recent research suggests a different mechanism: DEET appears to activate certain olfactory receptors in mosquitoes that they find unpleasant, effectively repelling them rather than hiding you from them. This explains why DEET remains effective even in high-humidity conditions where human scent would normally be intensified.

DEET Concentrations and Protection Time

DEET products range from 5% to 100% concentration. The concentration affects duration of protection rather than effectiveness—a 30% DEET product repels mosquitoes just as effectively as a 100% product, but the higher concentration lasts longer. Here's a general guide:

• 10% DEET: Approximately 2 hours of protection
• 20% DEET: Approximately 4 hours of protection
• 30% DEET: Approximately 6-8 hours of protection
• 50%+ DEET: Up to 12 hours of protection

DEET Characteristics

DEET has several notable characteristics that affect user experience:

• Odour: Distinctive chemical smell that some find unpleasant
• Texture: Can feel oily or greasy on skin, particularly at higher concentrations
• Material interaction: May damage certain plastics, synthetic fabrics, leather, and painted surfaces
• Efficacy: Proven effective against virtually all mosquito species, plus ticks, flies, and other biting insects

Understanding Picaridin

Picaridin (also known as Icaridin or KBR 3023) was developed by Bayer in the 1980s and approved for use in Australia in 2004. It was designed to provide DEET-like protection without some of DEET's less desirable properties. The compound is derived from the same chemical family as black pepper.

How Picaridin Works

Picaridin works through a similar mechanism to DEET, interfering with the mosquito's ability to locate hosts. It blocks the insect's olfactory receptors, making it difficult for mosquitoes to detect the chemical cues that normally attract them to humans, such as carbon dioxide and lactic acid.

Picaridin Concentrations

Picaridin products in Australia typically range from 10% to 20% concentration:

• 10% Picaridin: Approximately 3-4 hours of protection
• 20% Picaridin: Approximately 8-14 hours of protection

Picaridin Characteristics

Picaridin offers several advantages that have made it increasingly popular:

• Odour: Nearly odourless or with a light, pleasant scent
• Texture: Lighter feel on skin, not greasy or oily
• Material interaction: Safe for use on all fabrics, plastics, and finished surfaces
• Efficacy: Comparable to DEET for most mosquito species

Head-to-Head Comparison

Effectiveness Against Australian Mosquitoes

Multiple studies conducted in Australian conditions have shown that DEET and Picaridin at equivalent concentrations provide similar levels of protection against common Australian mosquito species including Aedes vigilax (saltmarsh mosquito), Aedes notoscriptus (backyard mosquito), and Culex annulirostris (common banded mosquito).

However, some research suggests DEET may have a slight edge against certain aggressive species in tropical regions. For typical Australian outdoor activities, either ingredient at appropriate concentrations will provide effective protection.

Safety Profiles

Both DEET and Picaridin have excellent safety records when used as directed:

DEET Safety: Despite widespread use for over 70 years and billions of applications, serious adverse events are extremely rare. The most common issues are skin irritation (particularly at high concentrations) and eye irritation if accidentally applied to the face. DEET has been extensively studied in pregnancy and found safe for use by expectant mothers.

Picaridin Safety: With a shorter history but substantial research, Picaridin shows an even lower incidence of skin reactions than DEET. It's less likely to irritate sensitive skin and has a better cosmetic profile. Like DEET, it's considered safe for use during pregnancy.

Application and Reapplication

Both repellents should be applied to all exposed skin, though application experience differs:

DEET's oilier texture means it spreads differently—some find this helps achieve even coverage, while others find it unpleasant. Picaridin's lighter texture feels more like a moisturiser and absorbs more quickly into the skin.

Reapplication frequency depends on concentration and activity level. Both ingredients can be washed or sweated off, requiring reapplication. Picaridin may need slightly more frequent reapplication in hot, humid conditions, though 20% formulations generally match DEET's duration.

Choosing the Right Repellent for Your Situation

Choose DEET When:

• You're travelling to areas with very high mosquito density or aggressive species
• You need the longest possible protection duration (50%+ formulations)
• You're in areas where mosquito-borne diseases like malaria are present (international travel)
• You want a well-established ingredient with decades of safety data
• Maximum protection is priority over cosmetic feel

Choose Picaridin When:

• You prefer an odourless, non-greasy product
• You have sensitive skin prone to irritation
• You're wearing expensive outdoor gear or synthetic fabrics
• You're applying repellent on children (easier cooperation with pleasant-feeling products)
• You're using repellent daily and prefer a more comfortable feel
• You're applying near watches, sunglasses, or other items that might be damaged by DEET

Special Considerations

Use with Sunscreen

Both DEET and Picaridin should be applied after sunscreen. Apply sunscreen first, wait 15-20 minutes for absorption, then apply repellent. Some studies suggest DEET may slightly reduce sunscreen efficacy, so consider using a higher SPF when combining the products. Picaridin does not appear to interact with sunscreen formulations.

Use on Children

Both ingredients are approved for use on children over 3 months of age in Australia. Many parents prefer Picaridin for children due to its more pleasant feel and lack of odour, which can improve compliance. For children, use lower concentrations (10-20% for either ingredient) and apply sparingly.

Environmental Considerations

Both DEET and Picaridin have been detected in waterways, though typically at levels considered safe for aquatic life. If you're applying repellent before swimming in natural water bodies, consider reducing the amount applied or choosing physical protection methods instead.

The Bottom Line

Both DEET and Picaridin are excellent choices for mosquito protection in Australia. DEET remains the most studied and proven repellent, particularly valuable for extreme conditions. Picaridin offers comparable protection with a superior user experience for everyday use.

For most Australian families, having both options available makes sense: Picaridin for daily backyard use and routine outdoor activities, and a DEET product for camping trips, bushwalking, or travel to high-mosquito areas. The best repellent is ultimately the one you'll use consistently and correctly.