Lysine used as an animal-feed ingredient is subject to FDA oversight as a feed additive. The foreign manufacturer should be registered with FDA, and the product must meet applicable purity and labeling standards. USDA APHIS requirements may also apply if the product is of animal origin, though synthetic lysine is typically produced by fermentation.

Methadone and normethadone are DEA Schedule II controlled substances. Importation requires a valid DEA importer registration, compliance with annual import quotas, and advance notification to DEA. CBP will detain shipments that lack proper DEA authorization, and penalties for non-compliance are severe.

Amino-alcohols carry a hydroxyl (–OH) group as the additional oxygen function, while amino-acids carry a carboxylic acid (–COOH) group. The nature of the oxygen-bearing substituent — alcohol vs. acid — determines which subgroup applies; the product's functional group analysis or CAS number is the definitive classification reference.