Phenylalanine is a naturally occurring amino acid that is in the food you eat every day. It has many benefits and no toxicity or side effects when taken appropriately, as in the small doses in NeuroC3. It goes directly to dopamine and norepinephrine and is useful for energy, stress, fatigue, and pain. This is a widely used, safe essential amino acid produced by yeasts and bacteria as metabolic byproducts in the breakdown of protein.