: Federal law limits individuals to 3.6 grams per day and 9 grams per 30-day period . Retailers use a database like NPLEx to track these amounts in real-time.

: You must present a valid photo ID (e.g., driver's license or passport) at the time of purchase.

In the United States, you must be at least to purchase Sudafed and other products containing pseudoephedrine over the counter. Because pseudoephedrine is a key ingredient used to illegally manufacture methamphetamine, federal law requires retailers to keep these products "behind the counter" and verify the buyer's age and identity with a government-issued photo ID. Federal and State Requirements