In 2025, it feels like prescription weight-loss drugs have gone from mainstream to mania—we all know someone (or many someones) using them, and ads for different versions have taken over our social-media feeds. As with all things in high demand, more affordable knockoff versions also now abound—but unlike with Stanley cups and handbags, off-brand drugs can pose serious health risks. Perhaps unsurprisingly, an increasing number of people are overdosing on off-brand versions of popular prescription GLP-1 drugs like Wegovy and Zepbound. Rather than being made in tightly regulated facilities run by pharmaceutical companies, these “compounded” weight-loss drugs—often sold by telehealth companies—are mixed by licensed pharmacists or physicians and aren’t subject to the same rules and regulations as big-name, FDA-approved drugs. That doesn’t mean they’re necessarily unsafe, but they can be trickier to dose and administer, and their ingredients can sometimes be a bit of a wild card.
The result: Poison-control centers are seeing a steady increase in calls related to weight-loss drugs, and the FDA shared a report detailing severe gastrointestinal issues people are experiencing when using compounded GLP-1s. Symptoms can include nausea, severe dehydration, vomiting, diarrhea, abdominal pain, and constipation, sometimes serious enough to require medical attention or hospitalization. Overdosing on GLP-1s can also cause low blood sugar levels (hypoglycemia), potentially triggering confusion, fainting, seizures, or coma. It can even lead to gallstones or pancreatitis, a serious and potentially life-threatening condition.
One reason that overdosing is more of an issue with off-brand weight-loss drugs: These compounded versions aren’t FDA-approved, which means they’re not required to follow the same strict packaging and labeling requirements as brand-name, commercial meds, which can lead to people improperly measuring or administering doses. While most brand-name weight-loss drugs come in easy-to-use, prefilled pens, compounded versions require people to draw from vials to fill their own syringes. Sometimes, the syringes provided are much larger than needed, making it hard to gauge how much drug is drawn up. Adding even more room for error, some list dosing information in “units,” while others use milligrams or milliliters, which can lead to confused patients turning to online calculators and Reddit to confirm their proper dose, according to The New York Times. According to the FDA, people have mistakenly injected anywhere from five to 20 times their prescribed dose.
In other cases, user mistakes are not the issue—even healthcare professionals can sometimes miscalculate dosing for these unregulated drugs. There have been instances of patients being prescribed compounded weight-loss formulas in doses that are too high—whether there’s too much medication in each dose, doses are timed too frequently, or the amount of medication (or titration schedule) is upped too quickly.
Then there’s another glaring reason that overdosing on off-brand weight-loss drugs is an issue: It’s more difficult to confirm what ingredients a formula contains, and the potency and purity of those ingredients can be unclear. That‘s because the ingredients in compounded drugs aren’t held to the same stringent standards as those in brand-name options. In fact, there can be wide variation when it comes to which active and inactive ingredients off-brand weight-loss drugs employ. There have been instances of counterfeit weight-loss drugs that are contaminated, contain too much of a drug, or contain harmful ingredients being sold online—these are usually available for purchase without a legitimate healthcare provider’s prescription (big red flag).
Of course, there are also reasons why millions of people still choose to use off-brand weight-loss drugs—namely, ease, availability, and price. While brand-name weight loss meds generally cost from $500 to more than $1000 a month with insurance (coverage is still limited), compounded versions hover around $200 to $400. Yet it’s still important to factor in the potential health risks. Your safest bet when it comes to weight loss prescriptions, according to the FDA: Obtain a prescription from your doctor or other trusted healthcare provider, who will make sure you understand how to administer it properly. Fill that prescription at a state-licensed pharmacy.
All of that said, there can be times when compounded versions of drugs make sense, like when you have an adverse reaction to an ingredient in a commercial formula or when there are shortages of certain drugs. Until recently, GLP-1s were classified as “in short supply,” but the FDA is now cracking down on compounded versions, so they may soon become harder to find. In the meantime, if you do choose to use a compounded weight-loss drug, be sure to work with a trusted healthcare provider, who can advise you on the correct dose and titration schedule, as well as how to properly measure, draw up, and administer the drug—plus answer questions about any adverse reactions that may arise. If you do end up buying a weight loss drug via a website, here are some quick ways to confirm that an online pharmacy is legit.
