Increased stress is a major health concern because it can often exacerbate other ailments if left unchecked. Adaptogens such as L-theanine can be a great addition to the diet to combat stress and help the body adapt. This white paper provides the latest science-based evidence for L-theanine supplementation and explores its positive impact on stress reduction and cognitive function. It also dives into the potential mechanisms of action on how L-theanine works and presents the data on several clinical trials. Lastly, this paper will review the safety and absorption properties of L-theanine.