At a glance
| Chemical family | Synthetic pyrethroid — Type II (alpha-cyano group, causes tremor syndrome in insects) |
| CAS number | 52315-07-8 |
| Classification | Not classified by IARC. WHO Class II (moderately hazardous). EU CLP Acute Tox. 3 (H301, oral), STOT RE 2, Aquatic Acute 1 / Chronic 1. US EPA Group C (possible human carcinogen — based on limited mouse data; not confirmed) |
| Where you encounter it | Professional bed bug and pest treatments (applied to mattress seams, bed frames, baseboards); agricultural pest control; mosquito control; some indoor sprays |
| Sleep micro-environment relevance | Applied directly to mattress seams and bed frames during professional pest treatment. One of the most commonly used pyrethroids in residential pest control. Direct contact with the sleep environment |
Regulatory & certification status
| European Union | Approved active substance under the Plant Protection Products Regulation. Also authorised under the Biocidal Products Regulation for insect control (product types 18). CLP Acute Tox. 3 (H301), STOT RE 2. Regulatory |
| United States | EPA-registered insecticide for residential and agricultural use. Group C classification (possible human carcinogen — under review). Applied by licensed pest control operators to mattress seams and bed frames. Regulatory |
| Canada | PMRA-registered for residential and agricultural use. Pest Management Regulatory Agency re-evaluation completed. Regulatory |
| International | WHO Class II (moderately hazardous). Not IARC classified. WHO Pesticide Evaluation Scheme (WHOPES) approved for indoor residual spraying for malaria vector control. Regulatory |
What it is
Cypermethrin is a synthetic pyrethroid — a man-made analogue of the natural insecticidal compounds (pyrethrins) found in chrysanthemum flowers. It is a Type II pyrethroid, meaning it contains an alpha-cyano group that makes it more potent than Type I pyrethroids like permethrin. Cypermethrin acts by blocking voltage-gated sodium channels in insect nerve cells, causing paralysis and death. It is effective against a wide range of insects including bed bugs, cockroaches, mosquitoes, and agricultural pests. IARC has not evaluated cypermethrin for carcinogenicity. The US EPA initially classified it as Group C (possible human carcinogen) based on limited evidence of tumours in one mouse study, but this classification has not been confirmed by subsequent review.
Where it shows up in bedding
Cypermethrin is one of the most commonly used insecticides applied directly in the bedroom during professional pest treatment. Pest control operators spray cypermethrin on mattress seams, box spring interiors, bed frame joints, headboard crevices, and baseboards — the harbourage sites where bed bugs hide. After application, cypermethrin residues remain on these surfaces for weeks to months, providing ongoing insecticidal activity. During sleep, direct skin contact with treated surfaces and inhalation of volatilised cypermethrin contribute to exposure. The relatively low mammalian toxicity of pyrethroids means that properly applied residues are not expected to cause acute health effects in humans.
Citations
- WHO (2009). Cypermethrin. WHO Specifications for Pesticides Used in Public Health. Source Regulatory
- ATSDR (2003). Toxicological Profile for Pyrethrins and Pyrethroids. Source Regulatory
- EPA. Cypermethrin — Pesticide Fact Sheet. Source Regulatory
Frequently asked questions
Is cypermethrin on my mattress safe?
When applied by a licensed pest control operator according to label directions, cypermethrin residues on mattress seams are not expected to cause acute health effects in humans. Pyrethroids have relatively low mammalian toxicity compared to organophosphate insecticides. However, some individuals may experience temporary skin tingling (paraesthesia) from direct contact with treated surfaces. If you have concerns, encasing the mattress after treatment creates a barrier.
How long does cypermethrin last on surfaces?
Cypermethrin residues on indoor surfaces can remain active for several weeks to months, depending on the surface type and environmental conditions. UV light degrades cypermethrin on exposed surfaces, but in protected areas like mattress seams and bed frame joints, it persists longer. This persistence is intentional — it provides ongoing protection against re-infestation.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-07-08. If you find a factual error, contact us.