Test Details: Glutamic acid is a major mediator of excitatory signals in the brain and is involved in most aspects of normal brain function including cognition, memory and learning. It also regulates appetite, cognition, learning, memory, increases gut motility, improves libido and decreases sleep. Low glutamic acid levels indicate ammonia toxicity with symptoms such as headache, irritability and fatigue. High glutamate levels is suspected in anxiety, autism, bipolar disorder, depression, impulsivity and inability to focus.