L-Phenylalanine (Amino Acid)


Out of stock

Email when stock available

SKU: HWAPHEN150 Category: Tag:

L-Phenylalanine (Amino Acid)

HealthWise® L-Phenylalanine 150g

  • 100% pure powder
  • pharmaceutical grade
  • L-Phenylalanine
  • packed without fillers or flowing agents

Do you need L-Phenylalanine?  Take the amino acid test here.

Phenylalanine is found in 3 forms: L-phenylalanine, the natural form found in proteins; Dphenylalanine (a mirror image of L-phenylalanine that is made in a laboratory), and DLphenylalanine, a combination of the 2 forms.

Athletic and Other Uses

Metabolism: L-phenylalanine acts primarily on the digestive system and the metabolic rate.  One of phenylalanine’s primary functions is to serve as a precursor to the amino acid tyrosine, which in turn is needed to produce the hormone thyroxine.  Appetite Suppression: Phenylalanine also stimulates the release of cholecystokinin, a digestive system hormone that produces a feeling of satiety after eating and decreases interest in eating, as well as being a precursor molecule for the neurotransmitter norepinephrine, a compound that also plays a role in controlling appetite.

Depression: The body changes phenylalanine into tyrosine, which makes proteins, brain chemicals, including L-dopa, epinephrine, and norepinephrine, and thyroid hormones.  Pain Control: D Phenylalanine (but not L-phenylalanine) has been used to treat chronic pain.  Skin Conditions: Vitiligo. Phenylalanine is a precursor to melanin via L Tyrosine so is used in the treatment of Vitiligo along with sunlight therapy.


No more than 5 gram a day for any conditions.
More than 5 gm can cause neuropathies.
D, L-Phenylalanine competes with other amino acids. They have to be able to pass through the stomach and blood brain barrier without competition.
The consensus of experts recommends taking phenylalanine on an empty stomach 15-20 minutes before eating. Avoid taking them with other amino acids or other supplements.
It is recommended to start with 500-1,000 mg as soon as you awake. Some people may take another 500-1,000 mg 4-6 hours later.
Taking phenylalanine too close to bedtime may keep you awake.

Drug Interactions and Cautions

Monoamine Oxidase Inhibitors: Monoamine oxidase inhibitors (MAOIs) are an older class of antidepressants drugs that are rarely used now. 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).

Levodopa: A few case reports suggest that phenylalanine may reduce the effectiveness of levodopa (Sinemet), a medication used to treat Parkinson’s disease.  Antipsychotic drugs can interact with Phenylalanine,  these include chlorpromazine (Thorazine), clozapine (Clozaril), fluphenazine (Prolixin),
haloperidol (Haldol), olanzapine (Zyprexa), perphenazine (Trilafon), prochlorperazine (Compazine), quetiapine (Seroquel), risperidone (Risperdal), thioridazine (Mellaril), thiothixene (Navane), and others.


Melanoma patients should avoid taking L-phenylalanine and L-tyrosine. Certain cancers, such as melanoma, depend on these amino acids to fuel their growth.  Supplemental use of L-phenylalanine and L-tyrosine may raise or normalize blood pressure.

Insomnia may be a side effect if taken too close to bedtime.

Some researchers think L-phenylalanine use can cause a number of side effects, including high blood pressure, nausea, heartburn, difficulty sleeping and mood swings, especially irritability. This is usually due to high dosing.

Please note: This product is sold as a Food Only.
For specific conditions please consult your healthcare professional or ask one of our professional natural health practitioners here.

Weight 250 g
Dimensions 7 × 7 × 11 cm