L-phenylalanine (LPA) serves as a building block for the various proteins that are produced in the body. L-phenylalanine can be converted to L-tyrosine and subsequently to L-dopa, norepinephrine, and epinephrine. L-phenylalanine can also be converted (through a separate pathway) to phenylethylamine, a substance that occurs naturally in the brain and appears to elevate mood.
D-phenylalanine (DPA) is not normally found in the body and cannot be converted to L-tyrosine, L-dopa, or norepinephrine. As a result, DPA is converted primarily to phenylethylamine (a potential mood elevator). DPA also appears to influence certain chemicals in the brain that relate to pain sensation.
DLPA is a mixture of the essential amino acid LPA and its mirror image DPA. LPA is found in most foods that contain protein. DPA does not normally occur in food, but when synthesized in the laboratory, half appears as LPA and half as DPA. The combination supplement (DLPA) is often used because both components exert different health-enhancing effects.
Although rare, individuals whose diets are very low in protein may develop a deficiency of L-phenylalanine. Benefits of supplementation are typically achieved in the absence of an outright deficiency.
L-Phenylalanine promotes alertness; reduces hunger pangs; improves memory; antidepressant; helps in controlling pain, particularly arthritis; used to help treat Parkinson's disease; alleviates PMS symptoms. Should not be taken by diabetics, anyone suffering from anxiety attacks, high blood pressure, PKU or melanoma.
DLPA has been used in amounts ranging from 75 to 1,500mg per day.
Since DLPA competes with other amino acids for attachment on a common amino acid carrier in the body, it should not be taken with protein containing foods. Individuals taking prescription or over-the-counter medications should consult a physician before taking DLPA.
People with phenylketonuria must not supplement phenylalanine. Some research suggests that tardive dyskinesia patients may process phenylalanine abnormally. Until more is known, it makes sense for people with this condition to avoid phenylalanine supplementation.
D-phenylalanine (DPA) may be helpful for some individuals with Parkinson's disease. [Arzneimittelforsch 26: pp.577-9, 1976]
A recommended dosage is usually 2 to 3gm daily, depending on the severity of the vitiligo. For best absorption, L-phenylalanine should be taken in between meals.
A number of double-blind clinical trials have demonstrated that dosages of DLPA, the form commonly found in supplements, at doses as low as 150mg per day is effective in the treatment of some forms of depression.
D-phenylalanine (DPA) has been used to treat the chronic pain of osteoarthritis with both positive and negative results.