DL-Tryptophan from Mexico
DL-Tryptophan, an indole-containing aromatic amino acid with single oxygen function, is specified in additional U.S. note 3 to section VI, fitting HTS 2922.49.30.00. It is essential for serotonin synthesis in supplements.
Duty Rate — Mexico → United States
100%
Rate breakdown
9903.04.6093.5%Pharmaceuticals Annex IV: patented pharma articles — 100% floor rate
9903.05.900%Articles already subject to Section 232 (steel/aluminum/copper + derivatives, autos + parts, wood, medium/heavy vehicles + parts, semiconductors, patented pharma) — U.S. note 52(f)
Import Tips
• Include COA confirming no impurities exceeding chapter limits; subject to FDA import alerts for purity
• Pitfall: classifying racemic form as separate from L-form