L-tyrosine
L-tyrosine is an aromatic amino acid with a phenol group on its side chain. It is made by bacterial fermentation of sugars or, by some suppliers, by hydrolysis of proteins such as keratin, then purified and crystallized. It dissolves poorly in water at neutral pH, so brands use it mainly in capsules, tablets and powders, and buy N-acetyl L-tyrosine when they need a more water-soluble form.
Suppliers sell different products under the same name. Specify the one you need.
Standard white crystalline powder for capsules, tablets and powder blends.
L-tyrosine made by bacterial fermentation of corn, cassava or beet sugar; the source and any vegan statement appear on the supplier's spec.
L-tyrosine tested to the USP monograph, used where a compendial grade is required for supplements.
Finely milled grades that suspend better in drink mixes, since tyrosine does not dissolve well.
Compare each result with your own specification when the lot arrives.
Store L-tyrosine in tightly closed, lined containers in a cool, dry place away from light and strong odors, and reseal opened packs promptly. Protect from light, which can discolor the powder. 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 source (fermentation or protein hydrolysis) for each lot, and note color on receipt, since discolored lots may have been exposed to light or heat. Rotate stock FEFO.
Facts from regulators and standards bodies, each linked to its source.
21 CFR 172.320 lists L-tyrosine among the amino acids that may be safely used as nutrients added to foods.
Source: ecfr.gov (opens in a new tab)FDA's Substances Added to Food inventory lists L-tyrosine with the technical effects flavoring agent or adjuvant and nutrient supplement.
Source: hfpappexternal.fda.gov (opens in a new tab)Health Canada's L-Tyrosine natural health product monograph lists L-tyrosine ethyl ester and N-acetyl-L-tyrosine as source ingredients.
Source: webprod.hc-sc.gc.ca (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 crystalline, fermented (plant-sugar) grade, uSP grade and micronized. 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 and heavy metals and microbiology, each with its method, specification and result for that lot.
Store L-tyrosine in tightly closed, lined containers in a cool, dry place away from light and strong odors, and reseal opened packs promptly. Protect from light, which can discolor the powder. 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-tyrosine among the amino acids that may be safely used as nutrients added to foods. FDA's Substances Added to Food inventory lists L-tyrosine with the technical effects flavoring agent or adjuvant and nutrient supplement. Health Canada's L-Tyrosine natural health product monograph lists L-tyrosine ethyl ester and N-acetyl-L-tyrosine as source ingredients.
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