Nordihydroguaiaretic Acid (NDGA) from Canada
NDGA is a potent antioxidant polyphenol from creosote bush used in food preservation and pharmaceuticals. HTS 2907.29.90.00 covers this tetraphenolic lignan as 'other' polyphenol. Synthetic versions also commercially available.
Duty Rate — Canada → United States
110%
Rate breakdown
9903.04.6094.5%Except as provided in heading 9903.04.61, patented pharmaceutical articles as provided for in subdivisions (c) and (d) of U.S. note 40 to this subchapter
9903.05.2910%Except for products described in headings 9903.05.85–9903.05.93, articles the product of Canada, as provided for in U.S. note 52 to this subchapter
Import Tips
• Include prior sanction letters for food additive use
• Specify natural vs synthetic origin
• Document peroxide value for antioxidant efficacy