But even for people with means, buying from the infant-formula black market is not necessarily straightforward. Parents can’t order directly from the European formula companies, or an online retailer like Amazon; they have to go through eBay, Facebook buying/selling groups, or third-party websites that sometimes get shut down. (In some cases, depending on where parents are purchasing European formula, they might not even know that it’s illegal.) And whereas U.S. formulas range from $0.50 to more than $1.90 per ounce, Holle’s goat-milk formula costs about $2.20 per ounce on the black market, not including shipping. The total cost can run close to $300 a month, if a baby is exclusively formula-fed. In Europe, these same formulas cost about a third of what they’re marked up to in the U.S.

The potential problems go beyond just finding somewhere to buy European formula. In the past, the FDA has cracked down on the import of European formula by targeting the third-party websites that import and sell it online, and U.S. Customs seizes formula that it discovers at the border. (The FDA is now planning a process to temporarily allow in some formulas from abroad to alleviate the current shortage, provided they meet certain requirements.) Some safety concerns, too, make using European formula a bad idea, Porto said. The instructions typically aren’t in English, the preparation requires metric units, the ratio of water to powdered formula is different from the U.S. standard, and parents might not be alerted to recalls. There have been reports of parents mixing European formula wrong and giving their babies too little or too many calories as a result.