repellant

A repellent is a substance or device designed to deter pests from approaching or contacting humans, animals, or objects. Repellents aim to reduce bites, scratches, or damage without killing the target. They can be applied to skin, clothing, or environments and cover a broad range of organisms, from insects to mammals. The term is distinct from insecticides and attractants.

Types include chemical repellents applied to skin or clothing, natural plant-based formulations, and mechanical or environmental barriers. Chemical products often contain synthetic active ingredients such as DEET, picaridin, or IR3535, and some use oil of lemon eucalyptus (OLE/PMD). Natural repellents rely on essential oils and typically offer shorter duration. Mechanical barriers include bed nets, window screens, and treated fabrics.

Mechanisms include olfactory and gustatory disruption, causing avoidance or reduced landing. Efficacy depends on the pest species, concentration, duration, and environmental conditions; repellents reduce risk rather than guarantee protection.

Safety and regulation: many skin-applied repellents are approved by national agencies with labeling on age, concentration, and reapplication. Some ingredients may cause skin irritation or allergies; products should be used as directed, avoiding eyes, mouth, and broken skin, and washed off after use. Permethrin-treated clothing provides additional protection but should not be applied to skin.

Applications and limitations: repellents are used in outdoor recreation, travel, pest management, and public health campaigns to reduce disease risk. Limitations include variable duration, reduced effectiveness in rain, and potential environmental impacts. Ongoing research seeks new compounds and formulations to improve safety and efficacy.