Mild or Moderate Asthma With Allergic Sensitization

The purpose of this study is to learn more about if taking a supplement called 5-hydroxytryptophan (5HTP) can improve breathing and anxiety symptoms related to asthma. To help learn more subjects will either be assigned to a group that is taking the supplement (5HTP) or a group that is taking a placebo. This will be decided randomly. Later in the study subjects will crossover to the other group.There are 5 study visits over the course of about 12 weeks.