It is based on scientific studies human, animal, or in vitro , clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available.
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Your use of this information means that you agree to the Terms of Use. Learn how we develop our content. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated. Uses L-phenylalanine LPA serves as a building block for the various proteins that are produced in the body.
What Are Star Ratings? This supplement has been used in connection with the following health conditions: Used for Why 2 Stars. In one study, depressed people given L-phenylalanine experienced results comparable to those produced by an antidepressant. Several studies suggest that a synthetic version of phenylalanine called D-phenylalaline, may reduce pain by decreasing the enzyme that breaks down endorphins.
D-phenylalanine DPA decreases pain by blocking the enzymes that break down the body's natural painkillers. Clinical studies suggest DPA may inhibit some types of chronic pain. In one trial, D-phenylalanine DPA supplementation improved motor control and tremors in people with Parkinson's disease. L-phenylalanine, in conjunction with ultraviolet light exposure, may improve repigmentation of skin. In double-blind research, alcoholics treated with L-tyrosine combined with DLPA D,L-phenylalanine , L-glutamine, prescription L-tryptophan, plus a multivitamin had reduced withdrawal symptoms and decreased stress.
In double-blind research, alcoholics treated with DLPA D,L-phenylalanine combined with L-tyrosine, L-glutamine, prescription L-tryptophan, plus a multivitamin had reduced withdrawal symptoms and decreased stress. Supplementing with D-phenylalanine DPA has been shown to reduce chronic pain due to osteoarthritis. DPA inhibits the enzyme that breaks down some of the body's natural painkillers. D-phenylalanine has been used with mixed results to treat chronic pain, including pain caused by rheumatoid arthritis.
Possible Deficiencies People whose diets are very low in protein may develop a deficiency of LPA, although this is believed to be very uncommon. Interactions with Medicines As of the last update, we found no reported interactions between this supplement and medicines.
It is possible that unknown interactions exist. If you take medication, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist. The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects.
For details, refer to the manufacturers' package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist. Related Information. References 1. Previous Section: References Top of the page. All rights reserved. Search the Healthwise Knowledgebase. Help Healthwise Index.
Phenylalanine Uses L-phenylalanine LPA serves as a building block for the various proteins that are produced in the body. Preliminary uncontrolled and double-blind studies found that L-phenylalanine may enhance the effectiveness of ultraviolet for vitiligo. Highly preliminary evidence suggests that D-phenylalanine may be helpful for multiple sclerosis when combined with transcutaneous electrical nerve stimulation TENS.
Although D- and DL- phenylalanine are marketed as treatments for attention deficit disorder , they do not appear to be helpful.
A pair of double-blind comparative studies found that D- or DL-phenylalanine may be as effective as the antidepressant drug imipramine, and possibly work more quickly. The larger of the two studies compared the effectiveness of D-phenylalanine at mg daily against the same daily dose of imipramine. The results in both groups were statistically equivalent, meaning that phenylalanine was about as effective as imipramine.
D-phenylalanine worked more rapidly, however, producing significant improvement in only 15 days. Like most antidepressant drugs, imipramine required several weeks to take effect. The other double-blind study followed 27 people, half of whom received DL-phenylalanine to mg daily and the other half imipramine to mg daily.
L-phenylalanine has also been tried as a treatment for depression, but not in studies that could provide a scientifically meaningful result.
Unfortunately, there have not been any double-blind, placebo -controlled studies of phenylalanine for depression. This is too bad, since without such evidence we can't be sure that the supplement is actually effective.
The enzyme enkephalinase breaks down enkephalins, naturally occurring substances that reduce pain. D-phenylalanine but not L-phenylalanine is thought to block enkephalinase; this could lead to increased enkephalin levels, which in turn would tend to reduce pain.
However, as yet there is no meaningful evidence that it really works in this way. A small double-blind, placebo-controlled study reported evidence for the effectiveness of D-phenylalanine in chronic pain, 21 but a careful re-examination of the math involved showed that it actually proved little.
The long-term safety of phenylalanine in any of its forms is not known. Both L- and D-phenylalanine must be avoided by those with the rare metabolic disease phenylketonuria PKU.
The maximum safe dosages of phenylalanine have not been established for young children, pregnant or nursing women, or those with severe liver or kidney disease. There are some indications that the combined use of phenylalanine with antipsychotic drugs might increase the risk of developing the long-term side effect known as tardive dyskinesia, or worsen symptoms in those who already have it. Like other amino acids, phenylalanine may interfere with the absorption or action of the drug levodopa, which is used for Parkinson's disease.
Werbach MR. Heller B. Noncatecholic Phenylethylamines. Part 1. DL-phenylalanine versus imipramine: a double-blind controlled study. Arch Psychiat Nervenkr. Analgesia in mice and humans by D-phenylalanine: Relation to inhibition of enkephalin degradation and enkephalin levels. Adv Pain Res Ther. D-phenylalnine was not found to exhibit opiate receptor mediated analgesia in monkeys [letter].
Speak to your doctor about what dose is right for you. Because of the potential for side effects and interactions with medications, you should only take dietary supplements under the supervision of a knowledgeable health care provider. People with phenylketonuria PKU , and women who are breastfeeding or are pregnant, should not take phenylalanine supplements.
Aspartame, found in artificial sweeteners such as Nutrasweet, is a source of phenylalanine. People with PKU should not use aspartame. If you are pregnant, ask your doctor about using this artificial sweetener. DL-phenylalanine should not be used in people taking antipsychotic drugs, as it may cause or worsen symptoms of tardive dyskinesia TD.
TDs are involuntary movements of the tongue, lips, face, trunk, and limbs that can occur in people taking antipsychotic drugs long term. Doses higher than 5, mg a day may be toxic and can cause nerve damage. High quantities of DL-phenylalanine may cause mild side effects such as nausea, heartburn, and headaches. If you are currently being treated with medication especially the following medications , you should not use phenylalanine without first talking to your health care provider.
They include phenelzine Nardil , isocarboxazid Marplan , and tranylcypromine sulfate Parnate. Taking phenylalanine while taking MAOIs may cause a severe increase in blood pressure hypertensive crisis.
This severe increase in blood pressure can lead to a heart attack or stroke. People taking MAOIs should avoid foods and supplements containing phenylalanine. Baclofen: Phenylalanine may reduce absorption of baclofen Lioresal , a medication used to relieve muscle spasms.
Avoid taking Baclofen with a meal, especially one that is high in protein, or with phenylalanine supplements. Levodopa: A few case reports suggest that phenylalanine may reduce the effectiveness of levodopa Sinemet , a medication used to treat Parkinson disease.
Some researchers think phenylalanine may interfere with the absorption of levodopa and worsen the person's condition. Selegiline: L-phenylalanine and the selective MAO inhibitor selegiline Eldepryl, Deprenyl may strengthen the antidepressant effects of phenylalanine. They should not be taken together. Antipsychotic or neuroleptic drugs: L-phenylalanine may worsen TD, a side effect of these neuroleptic drugs.
These drugs include phenytoin Dilantin , valproic acid Depakene, Depakote , and carbamazepine Tegretol , among others. PKU: high plasma phenylalanine concentrations are associated with increased prevalence of mood swings. Mol Genet Metab. Camacho F, Mazuecos J. J Drugs Dermatol. Relatinships between phenylalanine levels, intelligence and socioeconomic status of patients with phenylketonuria.
J Pediatr. Dietary Guidelines for Americans Amino acid supplementation increases lean body mass, basal muscle protein synthesis, and insulin-like growth factor-I expression in older women. J Clin Endocrinol Metab. Epub ahead of print. Kliegman R. Nelson Textbook of Pediatrics. Philadelphia, PA: Elsevier Saunders; Targeted and combination treatments for vitiligo. Comparative evaluation of different current modalities in subjects.
Dermatol Ther.
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