Our cardiologists and nutritionists created CardioTea with L-Theanine to provide a supplement with even more antioxidants that supports a healthy loss of weight without added caffeine.* Using nutrients derived from green and black tea leaves, our Proprietary Blend is theaflavin and catechin enriched, including EGCG. The amino acid, L-Theanine, and polyphenols from tea catechins, EGCG, may help maintain a healthy immune system and support a healthy mood and alertness.* What is L-Theanine and what benefits does it have L-Theanine is an amino acid that has been shown to raise concentration levels while promoting relaxation and calm.* Can I get the same health benefits of tea by drinking it. It's possible, however, you would have to drink multiple cups of green and black tea every day. And when you drink tea, (as with most tea extracts) it is difficult to get enough antioxidants necessary to maximize the potential health benefits. Does CardioTea have any side effects CardioTea with L-Theanine is non-pharmocologic, and has no known side effects. Is there caffeine in CardioTea with L-Theanine Un most tea extracts, CardioTea with L-Theanine has a negligible amount of caffeine, less than 5 mg. One serving has approximately as much as you would find in a half cup of caffeinated green tea.