Your Nutrients

L-phenylalanine (LPA) serves as a building block for the various proteins that are produced in the body. LPA can be converted to L-tyrosine (another amino acid) and subsequently to L-dopa, norepinephrine, and epinephrine. LPA can also be converted (through a separate pathway) to phenylethylamine, a substance that occurs naturally in the brain and appears to elevate mood.

LPA is found in most foods that contain protein. DPA does not normally occur in food. However, when phenylalanine is synthesized in the laboratory, half appears in the L-form and the other half in the D-form. These two compounds can also be synthesized individually, but it is more expensive to do so. The combination supplement (DLPA) is often used because of the lower cost and because both components exert different health-enhancing effects.

People whose diets are very low in protein may develop a deficiency of LPA, although this is believed to be very uncommon. However, one does not necessarily have to be deficient in LPA in order to benefit from a DLPA supplement.

Depression (DPA, LPA, DLPA) Low back pain (DPA) Pain (DPA) Parkinson’s disease (DPA) Vitiligo (LPA) Alcohol withdrawal support (DLPA) Osteoarthritis (DPA) Rheumatoid arthritis (DPA)

The maximum amount of DLPA that is safe is unknown. However, consistent toxicity in healthy people has not been reported with 1,500 mg per day or less of DLPA, except for occasional nausea, heartburn, or transient headaches. When 100 mg of LPA per 2.2 pounds body weight or more was given to animals, a variety of complex problems occurred, leading two researchers to have concerns about potential toxicity of high amounts in humans. While these concerns were directed at LPA specifically, they are likely to be equally applicable to DLPA. Although no serious adverse effects have been reported in humans taking phenylalanine, amounts greater than 1,500 mg per day should be supervised by a doctor. People with phenylketonuria must not supplement with phenylalanine. Some research suggests that people with tardive dyskinesia may process phenylalanine abnormally. Until more is known, it makes sense for people with this condition to avoid phenylalanine supplementation. LPA competes with several other amino acids for uptake into the body and the brain. Therefore, for best results, phenylalanine should be taken between meals, or away from protein-containing foods. People taking prescription or over-the-counter medications should consult a physician before taking DLPA. At the time of writing, there were no well-known drug interactions with phenylalanine.

DLPA has been used in amounts ranging from 75–1,500 mg per day. This compound can have powerful effects on mood and on the nervous system, and therefore DLPA should be taken only under medical supervision. LPA has been used in amounts up to 3.5 grams per day. For best results, phenylalanine should be taken between meals, because the protein present in food can interfere with the uptake of phenylalanine into the brain, potentially reducing its effect.

L-tyrosine is a nonessential amino acid (protein building block) that the body synthesizes from phenylalanine, another amino acid. Tyrosine is important to the structure of almost all proteins in the body. It is also the precursor of several neurotransmitters, including L-dopa, dopamine, norepinephrine, and epinephrine.

Dairy products, meats, fish, wheat, oats, and most other protein-containing foods contain tyrosine.

Some people affected by PKU are deficient in tyrosine. Tyrosine levels are occasionally low in depressed people. Any person losing large amounts of protein, such as those with some kidney diseases, may be deficient in several amino acids, including tyrosine.

Stress Depression Phenylketonuria (for deficiency) Alcohol withdrawal support Parkinson’s disease

L-tyrosine has not been reported to cause any serious side effects. However, it is not known whether long-term use of L-tyrosine, particularly in large amounts (such as more than 1,000 mg per day) is safe. For that reason, long-term use of L-tyrosine should be monitored by a doctor. Vitamin B6, folic acid, and copper are necessary for conversion of L-tyrosine into neurotransmitters. Certain medicines may interact with L-tyrosine. Refer to drug interactions for a list of those medicines.

Most people should not supplement with L-tyrosine. Some human research with people suffering from a variety of conditions used 100 mg per 2.2 pounds of body weight, equivalent to about 7 grams per day for an average-sized person. The appropriate amount to use in people with PKU is not known, therefore, the monitoring of blood levels by a physician is recommended.

L-phenylalanine (LPA) serves as a building block for the various proteins that are produced in the body. LPA can be converted to L-tyrosine (another amino acid) and subsequently to L-dopa, norepinephrine, and epinephrine. LPA can also be converted (through a separate pathway) to phenylethylamine, a substance that occurs naturally in the brain and appears to elevate mood.

LPA is found in most foods that contain protein. DPA does not normally occur in food. However, when phenylalanine is synthesized in the laboratory, half appears in the L-form and the other half in the D-form. These two compounds can also be synthesized individually, but it is more expensive to do so. The combination supplement (DLPA) is often used because of the lower cost and because both components exert different health-enhancing effects.

People whose diets are very low in protein may develop a deficiency of LPA, although this is believed to be very uncommon. However, one does not necessarily have to be deficient in LPA in order to benefit from a DLPA supplement.

Depression (DPA, LPA, DLPA) Low back pain (DPA) Pain (DPA) Parkinson’s disease (DPA) Vitiligo (LPA) Alcohol withdrawal support (DLPA) Osteoarthritis (DPA) Rheumatoid arthritis (DPA)

The maximum amount of DLPA that is safe is unknown. However, consistent toxicity in healthy people has not been reported with 1,500 mg per day or less of DLPA, except for occasional nausea, heartburn, or transient headaches. When 100 mg of LPA per 2.2 pounds body weight or more was given to animals, a variety of complex problems occurred, leading two researchers to have concerns about potential toxicity of high amounts in humans. While these concerns were directed at LPA specifically, they are likely to be equally applicable to DLPA. Although no serious adverse effects have been reported in humans taking phenylalanine, amounts greater than 1,500 mg per day should be supervised by a doctor. People with phenylketonuria must not supplement with phenylalanine. Some research suggests that people with tardive dyskinesia may process phenylalanine abnormally. Until more is known, it makes sense for people with this condition to avoid phenylalanine supplementation. LPA competes with several other amino acids for uptake into the body and the brain. Therefore, for best results, phenylalanine should be taken between meals, or away from protein-containing foods. People taking prescription or over-the-counter medications should consult a physician before taking DLPA. At the time of writing, there were no well-known drug interactions with phenylalanine.

DLPA has been used in amounts ranging from 75–1,500 mg per day. This compound can have powerful effects on mood and on the nervous system, and therefore DLPA should be taken only under medical supervision. LPA has been used in amounts up to 3.5 grams per day. For best results, phenylalanine should be taken between meals, because the protein present in food can interfere with the uptake of phenylalanine into the brain, potentially reducing its effect.

L-phenylalanine (LPA) serves as a building block for the various proteins that are produced in the body. LPA can be converted to L-tyrosine (another amino acid) and subsequently to L-dopa, norepinephrine, and epinephrine. LPA can also be converted (through a separate pathway) to phenylethylamine, a substance that occurs naturally in the brain and appears to elevate mood.

LPA is found in most foods that contain protein. DPA does not normally occur in food. However, when phenylalanine is synthesized in the laboratory, half appears in the L-form and the other half in the D-form. These two compounds can also be synthesized individually, but it is more expensive to do so. The combination supplement (DLPA) is often used because of the lower cost and because both components exert different health-enhancing effects.

People whose diets are very low in protein may develop a deficiency of LPA, although this is believed to be very uncommon. However, one does not necessarily have to be deficient in LPA in order to benefit from a DLPA supplement.

Depression (DPA, LPA, DLPA) Low back pain (DPA) Pain (DPA) Parkinson’s disease (DPA) Vitiligo (LPA) Alcohol withdrawal support (DLPA) Osteoarthritis (DPA) Rheumatoid arthritis (DPA)

The maximum amount of DLPA that is safe is unknown. However, consistent toxicity in healthy people has not been reported with 1,500 mg per day or less of DLPA, except for occasional nausea, heartburn, or transient headaches. When 100 mg of LPA per 2.2 pounds body weight or more was given to animals, a variety of complex problems occurred, leading two researchers to have concerns about potential toxicity of high amounts in humans. While these concerns were directed at LPA specifically, they are likely to be equally applicable to DLPA. Although no serious adverse effects have been reported in humans taking phenylalanine, amounts greater than 1,500 mg per day should be supervised by a doctor. People with phenylketonuria must not supplement with phenylalanine. Some research suggests that people with tardive dyskinesia may process phenylalanine abnormally. Until more is known, it makes sense for people with this condition to avoid phenylalanine supplementation. LPA competes with several other amino acids for uptake into the body and the brain. Therefore, for best results, phenylalanine should be taken between meals, or away from protein-containing foods. People taking prescription or over-the-counter medications should consult a physician before taking DLPA. At the time of writing, there were no well-known drug interactions with phenylalanine.

DLPA has been used in amounts ranging from 75–1,500 mg per day. This compound can have powerful effects on mood and on the nervous system, and therefore DLPA should be taken only under medical supervision. LPA has been used in amounts up to 3.5 grams per day. For best results, phenylalanine should be taken between meals, because the protein present in food can interfere with the uptake of phenylalanine into the brain, potentially reducing its effect.