Nature's lab - l-theanine 200mg - 60 capsules l-theanine is an amino acid found primarily in certain plant species and is a constituent of green tea. L-theanlne works to mental calmness and relaxation without producing drowsiness by blocking excitatory stimuli receptors to the brain. L-theanine may also help regulate blood pressure within normal limits and promote healthy cognitive function. . Nature's lab l-theanine 200mg healthy - 60 capsules (60 servings)