{"hq_id":"hq-p-bdy-000012","name":"Insect repellent (DEET-based and alternatives)","category":{"primary":"personal_care","secondary":"outdoor protection / insect repellent","tags":["insect repellent","DEET repellent","mosquito repellent","picaridin repellent","IR3535 repellent","DEET safety children","DEET neurotoxicity","insect repellent skin absorption","tick repellent DEET","OFF! repellent","Deep Woods OFF","permethrin clothing repellent","insect repellent endocrine disruptors","DEET absorption","repellent children safety"]},"product_tier":"BDY","overall_risk_level":"low","description":"Insect repellents — principally DEET (N,N-diethyl-meta-toluamide), picaridin (icaridin), IR3535, and oil of lemon eucalyptus (OLE/PMD) — are applied directly to skin and clothing to prevent mosquito, tick, and biting fly contact. DEET (CAS 134-62-3) has been the dominant insect repellent active ingredient since its US military development in the 1940s and EPA registration for consumer use in 1957. DEET is highly effective and has a long safety record at concentrations of 10–30% for consumer use — but it has well-documented dermal absorption, CNS effects at high doses, and specific concerns for children under 2 and for high-concentration or repeated applications. DEET concentrations in consumer products range from 5% (short-duration protection, 1–2 hours) to 100% (extended protection, up to 12 hours) — the higher concentrations offer negligible additional protection beyond 30–50% but dramatically increase dermal absorption and toxicity risk. Children represent the highest-concern population: CDC and AAP guidelines recommend against DEET in infants under 2 months (or under 2 for some formulations), using the lowest effective concentration for children, and avoiding application to children's hands (hand-to-mouth transfer). Permethrin, used for clothing and gear treatment rather than skin, is a different class of repellent with distinct toxicity concerns (neurotoxicant — safe for treated fabric, toxic if applied to skin directly). The current CDC-recommended alternatives to DEET — picaridin 20%, IR3535 20%, OLE with 30% PMD — provide comparable protection with different toxicity profiles.","synthesis":{"derived_risk_level":"severe","synthesis_confidence":0.82,"synthesis_method":"compound_composition","context_used":"human_infant","context_source":"product_users","exposure_modifier":1.1,"vulnerability_escalated":true,"escalation_reason":"Infant exposure group","compounds_resolved":1,"compounds_total":1,"synthesis_date":"2026-03-27","synthesis_version":"1.0.0"},"hazard_summary":{"sensitive_populations":"pregnant women, children","overall_risk":"low","primary_concerns":["DEET CNS toxicity is well-documented at high doses — multiple case reports of seizures and encephalopathy in children following high-concentration DEET application or repeated use. DEET dissolves or degrades many synthetic polymers — including nylon, rayon, spandex, vinyl, and plastics."],"exposure_routes":"skin contact, inhalation"},"exposure":{"routes":["dermal","inhalation"],"contact_types":["skin_contact","inhalation"],"users":["adult","child","infant"],"duration":"acute_repeated","frequency":"seasonal","scenarios":["Dermal contact during handling of Insect repellent (DEET-based and alternatives) (acute_repeated contact)","Inhalation exposure during use of Insect repellent (DEET-based and alternatives)","Incidental mouthing or hand-to-mouth transfer by children"],"notes":"Insect repellent use is seasonal for most temperate-climate users but may be daily during summer months, camping trips, or in endemic vector-borne disease regions. Application to full exposed body surface area (arms, legs, neck, potentially face) creates substantial dermal dose. Aerosol spray application creates inhalation exposure during the spray event. Children are typically dosed by caregivers applying to all exposed skin surfaces — the caregiver handles concentrated product and also receives dermal exposure during application. Tropical travel and military/outdoor professional use involves daily application over weeks to months."},"consumer_guidance":{"red_flags":[{"indicator":"Applying 100% or 95% DEET products to children","meaning":"High-concentration DEET (>50%) provides no meaningful additional protection duration over 30–50% DEET for children, but significantly increases dermal absorption and CNS risk in the pediatric population. The case reports of DEET-associated encephalopathy and seizures in children predominantly involve high-concentration products applied repeatedly. Consumer products with 95–100% DEET are marketed for hunting and outdoor use and are available without restriction — they are not appropriate for application to children.","action":"For children, use 10–30% DEET maximum, or switch to picaridin 5–20% or IR3535. Apply repellent to clothing rather than directly to skin where possible. Apply to adult's hands first, then pat onto child's exposed skin — do not spray directly. Avoid application to hands (mouthing), around eyes, and under clothing. Reapply only as often as label directs."},{"indicator":"Spraying aerosol DEET repellent directly onto face","meaning":"Aerosol DEET spray directed at the face creates inhalation exposure (DEET vapor and propellant alcohol) and mucous membrane contact risk (eyes, lips, nasal membranes). This is a common application error — users spray the product in the direction of their head and neck rather than applying to hands first.","action":"Apply repellent to hands first, then spread onto face avoiding eyes and mouth. Do not spray aerosol near face or in enclosed spaces. Use lotion or wipe formulations for face application to better control the application site and amount."}],"green_flags":[{"indicator":"Picaridin 20% or EPA-registered OLE/PMD for children; DEET ≤30% applied correctly for adults","meaning":"Using the lowest effective concentration, applying only to exposed skin, and avoiding hands and face minimize DEET exposure while preserving protection. Picaridin and OLE/PMD alternatives eliminate the high-concentration DEET concern for children. Permethrin-treated clothing provides tick protection for outdoor activities without any skin-applied repellent needed.","verification":"EPA registration number on product label — all EPA-registered repellents are evaluated for efficacy and safety at labeled concentrations. CDC insect repellent guidance at cdc.gov/niosh/topics/repellent. EWG's Guide to Bug Repellents at ewg.org provides ingredient-level safety assessments for registered products."}],"what_to_ask":[{"question":"What is the DEET concentration in this product? Is it appropriate for use on children? Are picaridin or OLE/PMD alternatives available? What is the protection duration at this concentration?","why_it_matters":"DEET concentration determines both protection duration and absorption/toxicity risk — higher is not better above 30–50%. Children require lower concentrations or alternative active ingredients. Protection duration (not concentration) should drive product selection for the expected exposure period.","good_answer":"DEET 10–30% for children or adults with shorter exposure periods; 30–50% DEET for extended outdoor activities; or picaridin 20% / OLE/PMD 30% as lower-concern alternatives for all ages. Permethrin for clothing.","bad_answer":"100% DEET applied to children; product without EPA registration; unlabeled concentration; aerosol sprayed directly on face."}],"alternatives":[{"name":"Picaridin (20%)","notes":"Similar efficacy to DEET with potentially fewer skin irritation reports"},{"name":"Oil of lemon eucalyptus","notes":"Natural plant-based option; effective for several hours with lower toxicity concerns"},{"name":"Physical barriers (nets, clothing)","notes":"Risk-free alternative for sensitive populations; most suitable for controlled environments"}],"notes":null},"regulatory":{"applicable_regulations":[{"jurisdiction":"US","regulation":"EPA — Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA); EPA registration required","citation":null,"requirements":"Insect repellents containing DEET, picaridin, IR3535, and other active ingredients must be registered with EPA under FIFRA — registration includes efficacy and safety review. DEET has been continuously reviewed since its 1957 registration; EPA conducted a comprehensive DEET reregistration in 1998 concluding safety at labeled concentrations. Product labels are legally enforceable — using a product at concentrations or in ways not consistent with the label (e.g., applying to infants under 2 months) is a regulatory violation. FDA regulates sunscreen-repellent combination products as OTC drugs with stricter requirements.","compliance_status":null,"effective_date":null,"enforcing_agency":null,"penalties":null,"source_ref":"src_001"}],"certifications":[{"name":"FDA OTC/Cosmetic","issuer":"FDA","standard":"21 CFR Parts 700-740","scope":"Cosmetic ingredient safety, labeling requirements"},{"name":"EU Cosmetics Regulation","issuer":"European Commission","standard":"Regulation (EC) No 1223/2009","scope":"Cosmetic product safety, 1,600+ banned/restricted substances"}],"labeling":{"required_disclosures":[],"prop65_warning":{"required":null,"chemicals":[],"endpoint":null,"notes":null},"ghs_labeling":{"required":null,"signal_word":null,"pictograms":[],"hazard_statements":[],"notes":null},"hidden_ingredients":{"trade_secret_protected":null,"categories_hidden":[],"estimated_count":null,"known_concerns":null,"notes":null},"notes":null},"recalls":[],"regulatory_gap":null,"notes":null},"lifecycle":{"recyclable":false,"disposal_guidance":"Empty containers may be recyclable; do not pour chemicals down drain; check TerraCycle programs","hazardous_waste":false,"expected_lifespan":"months"},"formulation":{"form":"liquid","key_ingredients":[{"hq_id":null,"name":"DEET (N,N-Diethyl-m-toluamide)","role":"active","concentration_pct":"10-30"},{"hq_id":null,"name":"Water","role":"carrier","concentration_pct":"50-70"},{"hq_id":"hq-c-org-000023","name":"Ethanol","role":"solvent","concentration_pct":"5-10"},{"hq_id":"hq-c-org-000317","name":"Glycerin","role":"humectant","concentration_pct":"2-3"}],"certifications":[]},"materials":{"common":[{"material_id":null,"material_name":"DEET (N,N-diethyl-meta-toluamide) — primary active ingredient","component":"active insect repellent chemical","prevalence":"very_common","notes":"DEET is the active ingredient in OFF!, Deep Woods OFF, Sawyer, Repel, and most conventional consumer insect repellents. Consumer products range from 5% to 100% DEET concentration; spray, lotion, wipe, and wristband formulations. DEET is absorbed dermally at rates that increase with concentration — DEET at 100% achieves meaningful systemic concentrations measurable in blood and urine. DEET at consumer concentrations has a 60+ year safety record with relatively rare serious adverse events — but neurological effects (encephalopathy, seizures) have been reported with high-concentration or repeated application in children, and contact urticaria and blistering occur with high concentrations. Vehicle and excipient formulation (alcohol-based aerosols vs. cream formulations) affects absorption rate significantly."},{"material_id":null,"material_name":"Picaridin (icaridin) — alternative active ingredient","component":"alternative insect repellent","prevalence":"common","notes":"Picaridin (KBR 3023, icaridin; CAS 119515-38-7) is the primary CDC-recommended DEET alternative, registered for US consumer use since 2005. Picaridin at 20% provides mosquito and tick protection comparable to 20–30% DEET with lower dermal absorption, lower CNS concern, and better skin feel (DEET dissolves plastics; picaridin does not). Picaridin is used in Sawyer Picaridin, Natrapel, and various off-label formulations. Picaridin's toxicity profile at consumer use concentrations is lower concern than DEET, though long-term chronic exposure data is less extensive given its shorter market history."},{"material_id":null,"material_name":"Permethrin — clothing and gear treatment","component":"clothing/gear insecticide (not skin repellent)","prevalence":"common","notes":"Permethrin (CAS 52645-53-1) is a synthetic pyrethroid insecticide used for clothing, tent, and gear treatment — it is NOT applied to skin. Permethrin-treated clothing kills ticks and mosquitoes on contact; the EPA-registered formulations for clothing treatment maintain efficacy through multiple washes. Permethrin is a neurotoxicant (voltage-gated sodium channel disruptor); dermal absorption from permethrin-treated fabric is very low. Direct skin application (not the intended use) is associated with paresthesia and systemic toxicity. Permethrin is highly toxic to cats (deficient in glucuronide conjugation pathway) — treated clothing should not contact cats."}],"concerning":[{"material_id":null,"material_name":"DEET — CNS effects in children and high-dose systemic absorption","concern":"DEET CNS toxicity is well-documented at high doses — multiple case reports of seizures and encephalopathy in children following high-concentration DEET application or repeated use. The mechanism involves DEET inhibition of cholinesterase enzymes and effects on GABA receptor-mediated neuronal activity. Dermal absorption in children is higher than in adults (greater surface-area-to-body-mass ratio, thinner skin barrier). Products containing 95–100% DEET are available over-the-counter for consumers who will apply them to children — the CDC and AAP recommend using 10–30% DEET maximum for children and avoiding application under clothing, to hands, or near eyes and mouth. The concentration-effect relationship for DEET protection efficacy flattens above 30–50%: 100% DEET offers no meaningful extension of protection over 50% DEET but significantly higher absorption.","compounds_of_concern":["hq-c-org-000973"],"source_refs":["src_001"]},{"material_id":null,"material_name":"DEET — plastic/synthetic material damage and formulation solvents","concern":"DEET dissolves or degrades many synthetic polymers — including nylon, rayon, spandex, vinyl, and plastics. This is both a practical concern (DEET damages watch faces, eyeglass frames, and synthetic clothing) and an indicator of DEET's chemical reactivity with synthetic materials. Aerosol DEET formulations use alcohol (isopropanol, ethanol) propellants that enhance dermal penetration and contribute to inhalation exposure. Spraying DEET aerosol near the face for head/neck application creates inhalation and mucous membrane contact exposure that exceeds the dermal application pathway. DEET should be applied to hands first and patted on face — not sprayed directly.","compounds_of_concern":["hq-c-org-000973"],"source_refs":["src_002"]}],"preferred":[{"material_id":null,"material_name":"Picaridin 20% or OLE/PMD 30% — lower-concern DEET alternatives with equivalent efficacy","why_preferred":"Picaridin 20% (Sawyer Picaridin, Natrapel) and OLE-based repellents with 30% PMD (oil of lemon eucalyptus active component) are CDC-approved for mosquito and tick repellency with efficacy comparable to 20–30% DEET. Picaridin does not dissolve plastics, has lower dermal absorption, and has a favorable CNS safety profile. OLE/PMD is plant-derived but not equivalent to generic 'oil of lemon eucalyptus' — the CDC recommends only products with p-Menthane-3,8-diol (PMD) at 30%. For children, picaridin at 5–20% and IR3535 at 20% are preferred over high-concentration DEET. Permethrin-treated clothing provides tick protection without skin application for the highest-risk tick exposure scenarios.","tradeoffs":"Picaridin and OLE/PMD alternatives are less universally available than DEET in some retail environments. OLE/PMD is not recommended for children under 3. Picaridin at 5% has shorter protection duration than 30% DEET. DEET remains the most studied repellent with the longest safety record at appropriate concentrations — for adults in high-malaria-risk areas, 30–50% DEET is still a first-line recommendation. The concern is specifically high-concentration DEET in children and repeated high-dose application."}]},"compound_composition":[{"hq_id":"hq-c-org-000973","compound_name":"hq-c-org-000973","role":"compound_of_concern","typical_concentration":null}],"identifiers":{"common_names":["insect repellent"],"aliases":[],"manufacturer":null,"brands":[]},"brand_examples":[{"brand":"Generic Mass-Market Brand A","manufacturer":"Consumer Products Corporation","market_position":"mass_market","notable":"Widely available mass-market option"},{"brand":"Generic Mass-Market Brand B","manufacturer":"Consumer Goods Ltd","market_position":"mass_market","notable":"Popular budget alternative"},{"brand":"Premium Brand A","manufacturer":"Premium Consumer Inc","market_position":"premium","notable":"Upscale premium positioning"},{"brand":"Professional Brand","manufacturer":"Professional Products Co","market_position":"professional","notable":"Professional/salon-grade option"},{"brand":"Specialty Eco-Brand","manufacturer":"Natural Products Ltd","market_position":"premium","notable":"Sustainable/natural product line"}],"sources":[{"id":"src_001","type":"regulatory","title":"EPA DEET reregistration eligibility decision (RED) — safety and risk assessment","url":"https://www.epa.gov/ingredients-used-pesticide-products/deet","accessed":"2026-03-08","year":1998,"notes":"EPA comprehensive DEET safety review; dermal absorption data by concentration; children's exposure assessment; adverse event case report review; concentration-specific protection duration data; basis for DEET consumer safety characterization and pediatric guidance"},{"id":"src_002","type":"journal","title":"DEET neurotoxicity in children — case series and CNS adverse event documentation","url":"https://doi.org/10.1542/peds.93.3.472","accessed":"2026-03-08","year":1994,"notes":"Pediatric case series of CNS adverse events following DEET exposure; seizures and encephalopathy documentation; concentration and application pattern analysis; children's vulnerability factors; basis for pediatric DEET concentration restriction recommendations"},{"id":"src_003","type":"regulatory","title":"CDC — Insect repellent use and safety: DEET, picaridin, IR3535, OLE guidance","url":"https://www.cdc.gov/niosh/topics/repellent/","accessed":"2026-03-08","year":2023,"notes":"CDC consumer guidance on EPA-registered repellents; pediatric recommendations; comparison of DEET vs. alternatives; application best practices; concentration guidance by protection duration needed; basis for alternative repellent recommendation"}],"meta":{"schema_version":"4.0.0","last_updated":"2026-03-25","timestamp":"2026-05-02T18:21:35.162Z"}}