Supports increased demands Tyrosine, in its left-handed form (L-tyrosine), is one of the conditionally essential amino acids. In addition to being obtained through food (poultry, fish, dairy products and legumes), it can also be produced in the body from phenylalanine. L-tyrosine is a precursor of the hormones and neurotransmitters dopamine, noradrenaline and adrenaline, which are involved in a wide variety of processes in the body.