Price: $18.30
(as of May 20, 2026 19:45:40 UTC – Details)
Product description




More About L-Tryptophan
L-tryptophan supports the immune response because it is the body’s precursor to the kynurenines that regulate immunity. If needed, L-tryptophan converts to vitamin B-3 in the body, which supports circulation, a healthy nervous system, the metabolism of food, and the production of hydrochloric acid for the digestive system.*

L-Tryptophan (Tablets, Capsules, Powder)
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Customer Reviews
4.5 out of 5 stars 426
4.5 out of 5 stars 426
4.5 out of 5 stars 1,943
4.5 out of 5 stars 1,943
4.5 out of 5 stars 1,943
4.0 out of 5 stars 1
4.0 out of 5 stars 1
Price
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$18.30$18.30
$10.95$10.95
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$17.45$17.45
$10.98$10.98
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Form
Tablets
Tablets
Capsules
Capsules
Capsules
Powder
Powder
Quantity
60 Tablets
120 Tablets
60 Capsules
90 Capsules
120 Capsules
50 Grams
100 Grams
Suggested Use
1 tablet three times daily,
1 tablet three times daily,
1 capsule three times daily,
1 capsule three times daily,
1 capsule three times daily,
1/4 teaspoon three times day
1/4 teaspoon three times day
Serving Size
3
3
3
3
3
3/4 teaspoon
3/4 teaspoon
Serving Per Container
20
40
20
30
40
29
58
Suitable For Vegetarians
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✔
✘
✘
✘
✔
✔
Made In The USA
✔
✔
✔
✔
✔
✔
✔
Is Discontinued By Manufacturer : No
Product Dimensions : 1.3 x 1.3 x 1.6 inches; 1.6 ounces
Item model number : SN1980
Department : Health and Beauty>Health and Wellness
Date First Available : November 22, 2004
Manufacturer : Source Naturals
ASIN : B000GFHPNY
Best Sellers Rank: #65,353 in Health & Household (See Top 100 in Health & Household) #2,627 in Blended Vitamin & Mineral Supplements #3,272 in Sales & Deals
Customer Reviews: 4.5 4.5 out of 5 stars (426) var dpAcrHasRegisteredArcLinkClickAction; P.when(‘A’, ‘ready’).execute(function(A) { if (dpAcrHasRegisteredArcLinkClickAction !== true) { dpAcrHasRegisteredArcLinkClickAction = true; A.declarative( ‘acrLink-click-metrics’, ‘click’, { “allowLinkDefault”: true }, function (event) { if (window.ue) { ue.count(“acrLinkClickCount”, (ue.count(“acrLinkClickCount”) || 0) + 1); } } ); } }); P.when(‘A’, ‘cf’).execute(function(A) { A.declarative(‘acrStarsLink-click-metrics’, ‘click’, { “allowLinkDefault” : true }, function(event){ if(window.ue) { ue.count(“acrStarsLinkWithPopoverClickCount”, (ue.count(“acrStarsLinkWithPopoverClickCount”) || 0) + 1); } }); });
The essential amino acid L-tryptophan is the precursor of two natural compounds of great importance.*
Suggested Use: 1 capsule three times daily, between meals and preferably with fruit juice. To support restful sleep, take an additional 3 capsules before bed.
Allergies: Contains no yeast, dairy, egg, gluten, soy or wheat. Contains no preservatives, or artificial color, flavor or fragrance.
Over 40 Years of Trust. Source Naturals was created in 1982 by CEO Ira Goldberg to support each individual’s potential to enjoy optimal health.
Manufactured in the USA. Manufactured in Scotts Valley, CA, under the Good Manufacturing Practices (cGMPs) established by the US Food and Drug Administration (FDA).












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