Efficacy

• According to the University of Wisconsin, two published studies and one informal study tested the efficacy of vanilla as a natural mosquito repellent. All found little to no repellent activity in vanillin, which is the primary component of vanilla bean extract.
  
  

Potential

• The two published studies cited by the University of Wisconsin tried adding vanillin to some commercially available mosquito repellents. While ineffective as a mosquito repellent on its own, vanillin proved to be useful in increasing the efficacy of other repellents.
  
  

Alternatives

• According to University of Wisconsin, catnip oil proves to be an effective mosquito repellent in studies. However, commercially available mosquito repellents still provide more protection.