May 15, 2006: What is the efficiency and toxicity of Avon's Skin So Soft Bug Guard?

The active ingredient in Avon's Skin So Soft Bug Guard^TM is IR 3535 (ethylbutylacetylaminopropionate). The World Health Organization (WHO) has designated this product as safe and of low toxicity. The only reported side effects were mild skin irritation reported and eye irritation following accidental ocular exposure. Studies have not demonstrated any genotoxicity, carcinogenicity or mutagenicity associated with IR 3535.

The efficacy of IR 3535 in preventing tick and mosquito bites (which carried the risk of transmitted disease) has been compared to DEET, the most common insect repellent in commercially available products. A head-to-head evaluation of multiple insect repellents at various concentrations found IR 3535 (7.5%) as effective as DEET (7.5%)' Both products provided 3-4 hours of repellent effect in a laboratory setting. Off! Skintastic for Family^TM is 7.0 % DEET. Avon Skin So Soft Bug Repellent^TM does not list the concentration of IR 3535. However a previous study comparing repellents at various concentrations (utilizing similar methods) demonstrated IR 3535 repelled insects from skin for only 22.9 minutes of insect repellent benefits². The duration of repellant of other products was similar. Due to the conflicting evidence neither the CDC nor EPA endorses the use of IR 3535 to prevent tick or mosquito bites.

Avon also makes regular Skin So Soft bath oil and a suncare lotion that has anecdotally reported to have insect repellent action. The NEJM study included these products². The active ingredient (other than mineral oil) of the bath oil is uncertain. The suncare lotion contains 0.5% citronella oil. The time of protection provided was 9.6+8.8 minutes for the bath oil and 2.8+3.4 minutes for the suncare lotion.

When tick and mosquito borne illnesses are a concern, products with IR 3535 may provide effective protection from bites if reapplied according to label instructions. However evidence reveals DEET provide longer lasting protection.

Is DEET safe and effective?? See next week's question.

Thanks to Kim Barker PharmD, for submitting this question of the week. Tox thought: Stick with the DEET.

I am interested in any questions that you would like answered in "Question of the Week." Please e-mail me with any suggestions at donna.segern,Vanderbilt.edu

Donna Seger, M.D.

Medical Director, Tennessee Poison Center

•

•               1. Barnard DR, Xue RD. Laboratory Evaluation of Mosquito Repellents Against Aeds Albopictus, Culex nigripalpus, and Ochlerotatus triseriatus (Diptera:Culcidae). Journal of

Medical Entomology 2004; 41 (4): 726-730.

2. Fradin MS, Day JF. Comparitive Efficacy of Insect Repellents Against Mosquito Bites. New England Journal of Medicine 2002; 347 (1): 13-18.