Valerian is a flowering plant native to Europe and Asia, and its root is traditionally used to promote relaxation and sleep. Early studies suggest that the ingredients in valerian root interact with GABA by increasing 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 leads to a feeling of calm and serenity (1, 2).