Tryptophan
L-tryptophan is an essential amino acid naturally present in dietary protein. A 1989 contamination event in a single manufacturer's supplement caused eosinophilia-myalgia syndrome (EMS); the contaminant, not tryptophan itself, was implicated.
What it is
An essential amino acid (L-tryptophan) required for protein synthesis and a precursor to serotonin and niacin.
Nutritional supplement, fortificant, and component of dietary protein.
Why it's flagged
- historical contamination concerns from poorly manufactured supplements
- drug interactions with serotonergic medications
What regulators actually say
"Amino acids... may be safely used in foods."
"L-tryptophan is an essential amino acid that must be obtained from the diet."
Regulatory status
United States — FDA
Permitted in dietary supplements and as a fortificant; 21 CFR 172.320 (amino acids in food).
European Union — EFSA
Approved as a flavoring/nutrient source; ADI not established for the amino acid itself.
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