RecruitingEarly Phase 1Clinical trialL-Theanine to Support Relaxation and Mood for Cancer Patients in SurveillanceThis clinical trial tests the feasibility, best dose, and effectiveness of L-theanine for supporting relaxation and mood among cancer patients in surveillance. L-theanine is a substance found in the leaves of green tea with potential to enhance mental health and well-being. It works by increasing certain chemicals within the body that have been associated with stress reduction, mood stabilization, and improved cognitive performance.