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Source Naturals, L-Tryptophan, 1.77 oz (50 g)

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$19.99 (50)
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In Stock
  • Expiration Date: Jul 2019
  • Shipping Weight: 0.19 lbs (0.09 kg)
  • Product Code: SNS-01998
  • UPC Code: 021078019985
  • Package Quantity: 1.77 oz (50 g)
  • Dimensions: 2.2 x 2.2 x 4 in, 0.15 lbs (0.07 kg)
Product Overview


  • Mood, Relaxation, Sleep
  • Dietary Supplement

The essential amino acid L-tryptophan helps support relaxation, restful sleep, and feeling better. It plays a part in the synthesis of both melatonin and serotonin, hormones involved with mood and stress response. L-Tryptophan also supports immune functions because it is the body's precursor to the kynurenines that regulate immunity. If needed, L-tryptophan converts to niacin in the body, which supports circulation, a healthy nervous system, the metabolism of food, and the production of hydrochloric acid for the digestive system. Source Naturals L-Tryptophan is extremely pure and is regularly tested to ensure the highest standards of quality.

Suggested Use

1/4 teaspoon three times daily, between meals and preferably with fruit juice. To support restful sleep, take 3/4 teaspoon before bed.

Other Ingredients

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.


If you are pregnant, may become pregnant, breastfeeding, or are taking medications such as SSRI's or MAOI's consult your health care professional before using this product.

Store in a cool, dry place.

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

Supplement Facts
Serving Size: 3/4 Teaspoon (approx. 1.5 g)
Servings Per Container: 33
  Amount Per Serving % DV
L-Tryptophan 1.5 g
† Daily Value not established.
iHerb Customer Reviews


Posted by 5554902050186171698 on Jul 19, 2016

Excellent nights sleep, no headache.

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Take with Gaba

Posted by Reviewer1385103 on Oct 10, 2012

I take a dose of this and a dose of Gaba for an excellent nights sleep. I have given this to habitual insomnacs and they have slept through the night for the first time in years.

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Good source of Tryptophan...

Posted by Reviewer1907202 on Jan 03, 2011

...if you want to be able to measure doses more precisely than what comes in capsules.

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Amazing results

Posted by Reviewer1814780 on May 22, 2010

This review is for L-Tryptophan, and this brand works great. I have not tried any other brand, however. We use 1/4 tsp, 3 times/day, (per Dr. Daniel Amen), and it has significantly reduced everyday stress and anxiety. We just take things more in stride. We tried 5-HTP first, but this works much better for us.

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This is great

Posted by Reviewer3080687 on Nov 20, 2008

I love having it in powder form without the fillers. Getting the extra tryptophan makes my body flow more normally with the rhythms of the day -- like going to sleep at the right time. It a very effective product for me.

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