<s>[INST] what chemicals does l-theanine affect [/INST] Theanine is an amino acid found in tea and some mushrooms. It comes in two forms: L-theanine and D-theanine. L-theanine is the most common form. L-theanine may affect the levels of certain chemicals in the brain. These include serotonin and dopamine, which influence mood, sleep, and emotion, and cortisol, which helps the body deal with stress.</s>\ <s>[INST] What does D-theanine do then? [/INST] 