L-Phenylalanine Capsules

L-phenylalanine, an essential amino acid for better mood.✝

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Sachet of 6 caps x 600mg Bottle of 120 caps x 600mg


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What is L-phenylalanine?

L-phenylalanine is the natural form of Phenylalanine (Phe). Phenylalanine is an essential amino acid and a precursor to tyrosine and thyroid hormones.2 “Essential” means that Phenylalanine must be included in the diet as it cannot be synthesized in the body from other precursors. Some of the best natural sources of Phenylalanine are eggs, fish, chicken, pork, nuts and cheese. It can also be obtained from products.

L-phenylalanine is a building block of many proteins, enzymes and brain chemicals. L-phenylalanine influences the rates of synthesis and release of dopamine, epinephrine and norepinephrine (collectively called catecholamines) neurotransmitters.2 The synthesis of neurotransmitters has been shown to be directly dependent on the brain concentrations of their precursor (i.e., L-phenylalanine).1 Dopamine is a unique neurotransmitter with both excitatory and inhibitory properties. For example, dopamine helps with depression, regulates mood and enhances mental alertness.

Other reported benefits following the use of L-phenylalanine include improved memory, boosted energy levels and even reduced chronic pain. Due to its ability to relieve pain, some users take L-phenylalanine to treat migraines and other headaches. On the other hand, symptoms of Phenylalanine deficiency include confusion, lack of energy, depression, decreased alertness, memory problems and lack of appetite.3

Key benefits:

  • Stress relief and mood enhancer
  • Increases alertness and concentration
  • Elevates dopamine and norepinephrine levels

Recommended dosage:

The recommended daily dosage of L-Phenylalanine appears to vary widely from 100 mg to 2000 mg.  But it is not recommended to take more than 2000 mg/day.

Chemical structure:

Phenylalanine chemical structure

Mechanisms of action:

Upon ingestion Phenylalanine crosses the blood-brain barrier (BBB) and enters the central nervous system where it is converted to neurotransmitters that start to elicit their effects.

Side effects:

L-Phenylalanine is generally considered to be safe and well-tolerated. However, you should not exceed the recommended dosages (see above) as you may have negative health effects. Overconsumption of L-Phenylalanine products may cause headaches, hypertension and anxiety. L-Phenylalanine products are not recommended for pregnant women, people with high blood pressure and those taking monoamine oxidase inhibitors (MAOIs). 

Compound facts:

Serving size: 1 capsule

Servings per bottle: 120

Amount per serving: L-Phenylalanine 600mg

This product is free from: Artificial Flavours, Colours & Preservatives, Lactose, Yeast & Gluten

Suitable for: Vegetarians and Vegans


  • Dietary products should not be used as a substitute for a well-balanced and healthy diet.
  • Store in a cool dry place, out of reach of children.
  • Do not use if you are pregnant or breastfeeding.


✝ These statements have not been evaluated by the Food and Drug Administration (FDA) The above products are not intended to diagnose, treat, cure or prevent any disease. You should consult a physician before taking a new product or a nootropic. This product should not be taken by pregnant or nursing mothers, people suffering from cardiovascular disease or those under 18 years of age.

Any studies cited here are not conclusive and are limited to their closed environment nature; they might not determine ones experience with a nootropic, due to a large number of unaccounted variables falling outside the scope of such studies.

The reviews available here are the opinions of contributors who may or may have not used these products, and do not necessarily represent the views of ThoughtFoods. These reviews represent one’s opinion and should not be taken as fact or recommendation. ThoughtFoods makes no warranty to the accuracy of information provided by these reviews.

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1. Fernstrom, J.D. (1977). Effects of the diet on brain neurotransmitters, Metabolism. 26 (2), 207-23.

2. Fernstrom, J.D. & Fernstrom, M.H. (2007). Tyrosine, phenylalanine, and catecholamine synthesis and function in the brain, J Nutr. 137, 1539-47S.

3. http://umm.edu/health/medical/altmed/phenylalanine

L-Phenylalanine Capsules Reviews

ThoughtFoods L-Phenylalanine Capsules

5(based on 1 reviews)

By on 11 May 2016
L-phenylalanine capsules are effective
I did a mini-experiment to test the effectiveness of L-phenylalanine on myself. So I bought a bottle of L-phenylalanine 3 weeks ago and been using it daily hoping to see improvement in my mental energy levels, alertness and general mood (wanted to be less moody). 2.5 weeks in, I decided to stop taking it for a couple of days just to check if I’ll notice any difference. Mind and mood were definitely affected in a negative way, which made me start taking L-phenylalanine again. Even my girlfriend said that I wasn't the same when I wasn't taking L-phenylalanine capsules.
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