Melts Fast, Flavor Lasts Since 1932 Innovative Quality Sugar Free Dietary Supplement 1 Daily Instant Dissolve KAL L-Theanine ActivMelt micro tablets quickly in the mouth and are designed for optimal absorption in the body. L-Theanine is a water-soluble amino acid studied for its reputed role in providing nutritive support during times of stress. Found mainly in Green and Black Tea, L-Theanine has been studied for its role in weight management, brain and heart health.