The US Food and Drug Administration (FDA) has sent numerous warning letters to compounding pharmacies for illegally selling semaglutide and tirzepatide, or producing adulterated or misbranded versions. The FDA told the that between August 2021 and mid-July 2024, it reviewed 288 reports of patients having bad reactions to compounded and 108 such reports for tirzepatide. Some patients required hospitalisation.

Although shortages , manufacturers are still struggling to keep up with high demand for these weight-loss drugs. Some patients are turning to compounding pharmacies when they cannot access the branded version of these drugs due to a shortage or other barriers such as cost and insurance coverage. However, the FDA, Eli Lilly (Indianapolis, IN, US), and (Bagsvaerd, Denmark) have all expressed quality and safety concerns with compounded weight loss drugs.

The organisations found that some compounded versions of semaglutide and tirzepatide were counterfeit, contained too little, too much or no active ingredient at all, or contained the wrong or harmful ingredients. The gold standard of business intelligence. Compounding is a well-established practice that allows for the customisation of dosage, formulation and delivery method to meet the specific needs of individual patients, such as for patients with an allergy to one of the inactive ingredients in the approved drug or for a patient who has trouble swallowing a tablet or capsule and needs medicine in a liquid form that is not.