Supports balanced mental health and emotional wellbeing. Maintains a feeling of calm while remaining alert. Get the most out of your life by de-stressing with Suntheanine L-Theanine! This unique amino acid has been extensively researched and shown to promote relaxation without causing drowsiness. Swanson Ultra, featuring patented SunTheanine, offers a safe and effective alternative to help you keep up the pace with a smile on your face! Vegetarian. Dietary Supplement.