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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.

DLPA has been used in amounts ranging from 75 to 1,500mg per day. Consistent toxicity in healthy people has not been reported with 1,500mg per day or less of DLPA, except for occasional nausea, heartburn, or transient headaches.
This compound can have powerful effects on mood and on the nervous system, and therefore DLPA should be taken only under medical supervision.

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.

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.


Phenylalanine can help with the following:
Aging  Parkinson's Disease / Risk
 D-phenylalanine (DPA) may be helpful for some individuals with Parkinsonís disease. [Arzneimittelforsch 26: pp.577-9, 1976]


Not recommended for:
  Histapenia (Histamine Low)


 Phenylalanine can affect depression via three separate pathways.
  1. D-phenylalanine (DPA) exerts antidepressant activity due to its metabolism to phenylethylamine (PEA).
  2. DPA inhibits the breakdown of the body's endogenous opiates thus producing a state of euphoria.
  3. Phenylalanine is an important precursor for the production of noradrenaline and adrenaline thus increasing the body's ability to cope with stress.
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.


  Rheumatoid Arthritis
 The 'D' form of phenylalanine (DPA) has been used to treat chronic pain, including rheumatoid arthritis, with mixed effectiveness.

 D-phenylalanine (DPA) has been used to treat the chronic pain of osteoarthritis with both positive and negative results.


  Low Back Pain / Problems
 The brain responds to pain signals by producing and activating morphine-like hormones called endorphins. This pain relief effect lasts for about 30 hours (longer than known analgesics), and without side effects when given frequently. It was discovered that d- and dl-Phenylalanine (DLPA), but not l-Phenylalanine, inhibit several of the enzymes responsible for endorphin destruction. DLPA appears to restore endorphin levels to a normal range, while simultaneously producing a reduction in pain. It often equals or exceeds morphine or other opiate derivatives in its effect and is non-addictive. Start with 500mg qd and work up to 3 or 4gm qd. This is a precursor for epinephrine and phenylethylamine (PEA). PEA has amphetamine-like stimulant properties. Chocolate contains high levels of PEA.

May do some good
Likely to help
May have adverse consequences


Amino Acid:  An organic acid containing nitrogen chemical building blocks that aid in the production of protein in the body. Eight of the twenty-two known amino acids are considered "essential," and must be obtained from dietary sources because the body can not synthesize them.

DLPA:  D.L-Phenylalanine: A 50-50 mixture of d-phenylalanine and l-phenylalanine. May help alleviate chronic pain by increasing endorphin activity (the body s natural painkillers).

Dyskinesia:  A condition characterized by spasmodic, uncoordinated, or other abnormal movements; i.e., those which result from a reaction to phenothiazines.

Milligram:  (mg): 1/1,000 of a gram by weight.

Nausea:  Symptoms resulting from an inclination to vomit.

Nervous System:  A system in the body that is comprised of the brain, spinal cord, nerves, ganglia and parts of the receptor organs that receive and interpret stimuli and transmit impulses to effector organs.

Noradrenaline:  (Norepinephrine): A catecholamine hormone secreted from the adrenal medulla and post-ganglionic adrenergic fibers in response to hypotension or emotional stress.

Over-The-Counter:  A drug or medication that can legally be bought without a doctor's prescription being required.

Phenylalanine:  Essential amino acid needed for the normal growth of infants and children. It is also needed for normal protein use all through life. Precursor to tyrosine which is used to manufacture certain hormones (epinephrine, norepinephrine, dopa, dopamine) which are important for the transmission of nerve impulses. As neurotransmitters, these substances are believed to influence mood, appetite control and memory. It is found in large amounts in milk, eggs, and other common foods.

Phenylketonuria:  An inherited disease caused by a lack of an enzyme necessary for converting phenylalanine into a form the body can use.

Protein:  Compounds composed of hydrogen, oxygen, and nitrogen present in the body and in foods that form complex combinations of amino acids. Protein is essential for life and is used for growth and repair. Foods that supply the body with protein include animal products, grains, legumes, and vegetables. Proteins from animal sources contain the essential amino acids. Proteins are changed to amino acids in the body.