Evidence supporting the use of: Castile soap
For the health condition: Insect Repellant

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Synopsis

Source of validity: Traditional
Rating (out of 5): 2

Castile soap has been traditionally used as a component in homemade insect repellents and sprays for plants rather than as a direct repellent for humans. The practice is rooted in the soap’s ability to act as a surfactant, breaking down the waxy protective outer layer of certain soft-bodied insects (such as aphids and mites), which can dehydrate and eventually kill them. Historically, gardeners and farmers have used diluted Castile soap sprays as a non-toxic alternative to chemical pesticides to manage insect pests on crops and houseplants.

However, there is little scientific evidence that Castile soap alone acts as an effective insect repellent in the sense of preventing insects from landing on or biting humans. Its efficacy is more related to insecticidal (killing) action on contact with insects on plants rather than repelling them. Scientific literature supports the use of soap sprays for pest control in agriculture and horticulture but does not support Castile soap as a standalone personal insect repellent.

In summary, the use of Castile soap is primarily justified by traditional practice in plant care rather than scientific studies demonstrating its repellent effects on insects that bite humans.

More about castile soap
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Products containing castile soap

We currently have no products on Vitabase that contain this ingredient.