L-tryptophan
L-tryptophan is an essential aromatic amino acid with an indole side chain. Commercial L-tryptophan is made by bacterial fermentation of sugars, then purified, often with activated carbon treatment and recrystallization, to a white to off-white powder. Its trace impurity profile is watched closely, and brands usually buy compendial (USP) grades from suppliers with documented purification for capsules, tablets and powders.
Suppliers sell different products under the same name. Specify the one you need.
L-tryptophan tested to the USP monograph, used where a compendial grade is required for supplements.
L-tryptophan tested to a Food Chemicals Codex or supplier food specification for use in foods and drink mixes.
L-tryptophan made by bacterial fermentation of corn, cassava or beet sugar; the source and any vegan statement appear on the supplier's spec.
Milled grades for capsule filling and powder blends.
Compare each result with your own specification when the lot arrives.
Store L-tryptophan in tightly closed, lined containers in a cool, dry place away from light and strong odors, and reseal opened packs promptly. Protect it from light and heat, which cause yellowing. Shelf life or retest date is set by the supplier's specification; assay, loss on drying and micro are the usual retest points for older stock.
Record assay and related-compound results for each lot, keep the manufacturer and site on file, and do not accept lots without a full impurity profile. Note color on receipt and rotate stock FEFO.
Facts from regulators and standards bodies, each linked to its source.
21 CFR 172.320 lists L-tryptophan among the amino acids that may be safely used as nutrients added to foods.
Source: ecfr.gov (opens in a new tab)Under 21 CFR 172.320, added plus naturally present L-tryptophan may not exceed 1.6 percent by weight of the total protein of the finished food.
Source: ecfr.gov (opens in a new tab)FDA's Substances Added to Food inventory lists L-tryptophan with the technical effect nutrient supplement and cites 21 CFR 172.320.
Source: hfpappexternal.fda.gov (opens in a new tab)This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.
Manufacturers and distributors whose own websites say they sell it.
Manufacturer · Raleigh, NC
North American subsidiary of the Ajinomoto Group. It supplies pharmaceutical- and food-grade amino acids made by fermentation, in pack sizes from R&D pails to bulk, plus custom amino acid blends.
Suppliers are in alphabetical order and none pays to appear. Each claim is checked against the supplier’s own website on the date shown. Ask for the specification sheet and a recent COA before you order, and confirm details with the supplier.
Common forms include uSP grade, food grade, fermented (plant-sugar) grade and fine powder. Ask each supplier for the specification sheet of the exact grade they quote.
Expect identity, assay, related substances, loss on drying and residue on ignition, heavy metals and microbiology and absorbance and color of solution, each with its method, specification and result for that lot.
Store L-tryptophan in tightly closed, lined containers in a cool, dry place away from light and strong odors, and reseal opened packs promptly. Protect it from light and heat, which cause yellowing. Shelf life or retest date is set by the supplier's specification; assay, loss on drying and micro are the usual retest points for older stock.
21 CFR 172.320 lists L-tryptophan among the amino acids that may be safely used as nutrients added to foods. Under 21 CFR 172.320, added plus naturally present L-tryptophan may not exceed 1.6 percent by weight of the total protein of the finished food. FDA's Substances Added to Food inventory lists L-tryptophan with the technical effect nutrient supplement and cites 21 CFR 172.320.
Request a free listing for the ingredients you make or distribute. No paid placement.