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Source Naturals, L-Tryptophan, 500 mg, 60 Capsules

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In Stock
  • Product Code: SNS-01984
  • UPC Code: 021078019848
  • Package Quantity: 60 Capsules
  • Dimensions: 2.4 x 2.4 x 4 in, 0.15 lbs (0.07 kg)
  • Important Note:

    Due to Japanese Custom’s regulations, a maximum of three bottles per order can be imported into Japan.

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Product Overview


  • Dietary Supplement
  • Mood, Relaxation, Sleep
  • Non GMO Validated

The essential amino acid L-tryptophan helps support relaxation, restful sleep, and positive mood. It plays a part in the synthesis of both melatonin and serotonin, hormones involved with mood and stress response and sleep/wake cycles. 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 capsule three times daily, between meals and preferably with fruit juice. To support restful sleep, take 3 capsules before bed.

Other Ingredients

Gelatin (capsule), silica, magnesium stearate, dibasic calcium phosphate, and microcrystalline cellulose.

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.

Store in a cool, dry place.

If you are pregnant, may become pregnant, breastfeeding, or are taking medications such as SSRIs or MAOIs consult your health care professional before using this product.

Supplement Facts
Serving Size: 3 Capsules
Servings Per Container: 20
  Amount Per Serving: % DV
Iron (naturally occurring) 575 mcg 3%
L-Tryptophan 1.5 g
†Daily Value not established.
iHerb Customer Reviews

Now sleep is refreshing.

Posted by 4625241977939343939 on Jul 05, 2016

I have always had trouble with sleep - I now take 1 L-tryptophan together with 1 DL Phenylalanine in the evening and have a fantastic sleep. I don't sleep any longer, but sleep solid and wake up refreshed and clear headed; doesn't make me drowsy before or after I sleep, just put my head down and know I'm in for a good nights sleep. I have just re-ordered this product.

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Posted by 4905264755264477501 on Jun 26, 2016

I bought this to help with sleep, but after using it for some time now it's effect is minimal at best.

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Could not use this

Posted by 5340192616805474535 on Jun 23, 2016

This product along with me taking Elavil for depression made me so depressed I could not take it

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Reduced anxiety/better sleep

Posted by 5695473366341874989 on Oct 28, 2015

I notice a difference within half an hour. Unlike some medicines, I have no annoying side effects like short term memory loss. It also reduces my tendency to ruminate for ling periods. If I use this supplement as a sleeping aide, I don't feel groggy when I wake up. Very happy with this product.

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Good for sleep...

Posted by MikeMember on Jun 05, 2015

Along with melatonin, it helps me sleep through the night.

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