Federal prosecutors have asked judges in two states to authorize the seizure of more than 3,200 cases of controversial workout products from warehouses operated by GNC, the nation’s largest specialty retailer of dietary supplements.

With names like Jack3d and OxyElitePro, the workout products contain a stimulant called dimethylamylamine, or DMAA for short. In April, the Food and Drug Administration warned consumers that DMAA was an illegal dietary ingredient and that products containing the stimulant could elevate blood pressure, potentially leading to heart attacks.

After the agency’s warning, USPlabs, the maker of Jack3d and OxyElite Pro, said the company for business reasons had decided to stop making DMAA products. Some leading retailers withdrew their remaining stocks of DMAA products from store shelves, but GNC continued to sell its inventory.

Greg Miller, a spokesman for GNC, said in an e-mail on Friday that the company believed DMAA to be a “safe, legal dietary ingredient.”