ADHD drugs being sold online are most likely fake, according to the US Food and Drug Administration. The organization sent out warnings about dubious versions of Adderall, a drug that’s used to treat both ADHD and narcolepsy, that are currently being sold through various drug-peddling websites. Adderall is a controlled substance, which means it is addictive and subject to regulation.

The FDA states that the fake version of Adderall contain the wrong active ingredient. Spotting the differences between the two is relatively easy for those who have used the product in the past. The counterfeit pills are white with no visibile markings, while the real tablets are orange/peach in color and have “dp” printed on one side and 30 on the other. The number 30, of course, is a reference to the dosage.

“Consumers should be extra cautious when buying their medicines from online sources,” the FDA explained in a media statement. “Rogue websites and distributors may especially target medicines in short supply for counterfeiting.”

According to Daily Dose, Adderall is currently in very short supply, and has been for a while now. This may explain why so many knock-offs have started popping up online.

Other ways to identify the bogus pills include:

• Blister packaging
• Numerous misspellings on the packaging
• The pills, in addition to being white, are round and smooth

If you think you’ve gotten your hands on some counterfeit Adderall, pay a visit to the FDA’s MedWatch website and fill out a report.