Repellent Efficacy of Catnip (Nepeta cataria) Essential Oil and Its Topical Formulations Against Aedes aegypti

Abstract

This study evaluated the repellent efficacy of catnip (Nepeta cataria) essential oil and its potential for development into safe topical products. Pure catnip oil was first tested against Aedes aegypti using the Arm-in-Cage (AIC) method, providing complete protection (CPT) for 220.00 ± 6.32 minutes, thereby confirming its strong intrinsic repellent activity. To create user-appropriate products, a 20% dilution of catnip oil was incorporated into two topical prototypes: a spray and a gel. Both were assessed using the AIC method, with repellency recorded at 30-minute intervals over a 3-hour exposure period. The spray demonstrated a mean repellency of 84.70 ± 2.68%, while the gel maintained a slightly higher repellency of 91.83 ± 2.09%, with CPTs of 110.00 ± 20.00 and 130.00 ± 14.83 minutes, respectively. Skin patch testing confirmed that both formulations were well tolerated, with no irritation observed. To the best of our knowledge, this is the first study to evaluate catnip essential oil formulated into topical spray and gel prototypes and to assess both their repellency and skin tolerability in human volunteers. These findings indicate that catnip oil is an effective natural mosquito repellent and that 20% spray and gel formulations can provide safe, reliable protection against Ae. aegypti.