L-methionine
L-methionine is an essential, sulfur-containing amino acid. Commercial L-methionine is made by bacterial fermentation of sugars or by enzymatic resolution of chemically made DL-methionine, then purified and crystallized; the racemic DL form is made chemically and goes mainly into animal feed. Brands buy L-methionine as a white crystalline powder with a faint sulfur odor, mostly as one part of amino acid blends.
Suppliers sell different products under the same name. Specify the one you need.
Standard fine crystalline powder for capsules, tablets and dry blends.
L-methionine tested to the USP monograph, used where a compendial grade is required for supplements.
L-methionine tested to a Food Chemicals Codex or supplier food specification for use in foods and drink mixes.
The racemic mixture of D- and L-methionine, a cheaper chemically made grade; check whether your use permits it (21 CFR 172.320 excludes it from infant foods).
An acetylated derivative used as a source of L-methionine in foods under its own food additive regulation, 21 CFR 172.372.
Compare each result with your own specification when the lot arrives.
Store L-methionine in tightly closed, lined containers in a cool, dry place away from light and strong odors, and reseal opened packs promptly. Its sulfur odor can carry to nearby materials, so keep it away from flavors and finished goods. 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, source (fermentation or resolved synthetic) and optical rotation for each lot. Rotate stock FEFO.
Facts from regulators and standards bodies, each linked to its source.
21 CFR 172.320 lists L-methionine among the amino acids that may be safely used as nutrients added to foods, and lists DL-methionine as not for infant foods.
Source: ecfr.gov (opens in a new tab)Under 21 CFR 172.320, added plus naturally present L- and DL-methionine may not exceed 3.1 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-methionine with the technical effects flavor enhancer, flavoring agent or adjuvant, and nutrient supplement.
Source: hfpappexternal.fda.gov (opens in a new tab)Health Canada's Workout Supplements monograph lists L-methionine among its essential amino acids, with a dose range of 66.5 mg to 1 g per day.
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, uSP grade, food grade, dL-methionine and n-acetyl-L-methionine. 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-methionine in tightly closed, lined containers in a cool, dry place away from light and strong odors, and reseal opened packs promptly. Its sulfur odor can carry to nearby materials, so keep it away from flavors and finished goods. 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-methionine among the amino acids that may be safely used as nutrients added to foods, and lists DL-methionine as not for infant foods. Under 21 CFR 172.320, added plus naturally present L- and DL-methionine may not exceed 3.1 percent by weight of the total protein of the finished food. FDA's Substances Added to Food inventory lists L-methionine with the technical effects flavor enhancer, flavoring agent or adjuvant, and nutrient supplement. Health Canada's Workout Supplements monograph lists L-methionine among its essential amino acids, with a dose range of 66.5 mg to 1 g per day.
Request a free listing for the ingredients you make or distribute. No paid placement.