Passion flower is easy cultivated and fast-growing vine that has been traditionally used to treat insomnia and anxiety. Early studies suggest that the ingredients in passion flower interact with GABA by boosting GABA levels in the brain. GABA is an amino acid that is naturally present in every human body and acts in the brain as a "brake" on stress. So, more GABA in the brain may help you relax and sleep better (1, 2).