While Theanex Avis is generally well-tolerated, it is important to be aware of potential side effects. Some individuals may experience mild digestive discomfort, such as bloating or gas, when first starting Theanex Avis. These symptoms usually subside as the body adjusts to the supplement. It is also worth noting that Theanex Avis contains caffeine, so individuals who are sensitive to caffeine may experience jitters or difficulty sleeping if taken too close to bedtime.