Paraxanthine from Mexico
Paraxanthine, a caffeine metabolite, features dimethylxanthine structure with nitrogen hetero-atoms in fused rings, aromatic per 2933.99. Falls under U.S. note 3 products. Applied in sports nutrition and metabolic research.
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
• Provide stability data showing no degradation products above 0.1%
• Declare CAS number 611-59-6 on commercial invoice for CBP verification
• Avoid retail packaging to prevent reclassification under chapter 33 or 30