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Source Naturals, L-Phenylalanine, 500 mg, 100 Tablets

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In Stock
  • Expiration Date: Aug 2020
  • Shipping Weight: 0.24 lbs (0.11 kg)
  • Product Code: SNS-00161
  • UPC Code: 021078001614
  • Package Quantity: 100 Tablets
  • Dimensions: 2 x 2 x 3.5 in, 0.2 lbs (0.09 kg)
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Product Overview


  • Dietary Supplement
  • Free Form
  • An Essential Amino Acid

L-Phenylalanine, an essential amino acid, is a precursor of the amino acid tyrosine and a whole series of neurotransmitters and hormones. Phenylalanine is first converted to tyrosine, which becomes L-dopa, which converts to norepinephrine, a key neurotransmitter and an adrenal hormone. L-Phenylalanine is also a direct precursor of PEA (phenylethylamine), another important neurotransmitter.

Suggested Use

1 to 2 tablets daily.

Other Ingredients

Dibasic calcium phosphate, stearic acid, colloidal silicon dioxide, modified cellulose gum, and magnesium stearate.

Suitable for vegetarians and Hypoallergenic: contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor or fragrance.


Do not use if either tamper-evident seal is broken or missing. Keep out of the reach of children.

Contains phenylalanine. Not to be used by phenylketonurics, women who are pregnant, may become pregnant, or breastfeeding, or with antidepressant drugs such as MAOIs or SSRIs. If you have chronic high blood pressure, take after meals and/or consult your health care professional.

Supplement Facts
Serving Size: 2 Tablets
Servings Per Container: 50
  Amount Per Serving %DV
Calcium 99 mg 10%
L-Phenylalanine 1 g
†Daily Value not established
iHerb Customer Reviews

Good quality amino acid supplementation

Posted by 4985174333479468959 on Nov 03, 2016

I purchased this product on behalf of a friend, who had serious health issues and had been prescribed a mix of amino acids to overcome it (Round-up toxicity). She got on well, and felt the amino acids helped her greatly.

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truly effective. Quality is not excellent, fair price.

Posted by RudyMARYBallet on Jul 15, 2016

It has effect as L-phenylalanine certainly. easy price and quality is not special. so, suitable for quality.

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very nice product

Posted by HsienHsien on Apr 15, 2016

When I am very nervous, I will take a tablet of F and my nervous will reduce in few minute.

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Great Product

Posted by polarities on Mar 12, 2014

Happy Customer

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Good, but I prefer tyrosine

Posted by justkickingit on Aug 31, 2012

This is just a bit too activating for me, I get a light headache from it. Tyrosine works better for me. Caution if you have high anxiety or are prone to mania, seems to disrupt us a little more.

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