What happens if a shipment is held or seized at customs?

Here is the process, described factually — not advice on avoiding it. If the FDA believes an imported product appears to violate the law, it can detain the shipment and mail a Notice of Detention and Hearing to the importer, typically allowing around 20 days to respond with evidence. If the issue isn't resolved, the FDA issues a Notice of Refusal of Admission, and a refused shipment must be exported or destroyed under CBP/FDA supervision, generally within 90 days — the product is not delivered. For unapproved peptides, an active FDA Import Alert (66-78) can mean detention without physical examination. In practice this usually means losing the product and the money paid; consequences beyond that depend on specifics and jurisdiction — consult a licensed attorney.