The Obesity Society Statement on Safety Concerns Related to Compounded GLP-1
Rockville, MD – March 12, 2026 – Jacqueline M. Stephens, PhD, FTOS, President of The Obesity Society (TOS), the nation’s leading scientific organization dedicated to advancing the understanding, prevention, and treatment of obesity, released the following statement on reports that an impurity has been identified in compounded versions of tirzepatide mixed with vitamin B12. TOS has been an outspoken advocate for stronger oversight of compounded medications and recently signed a letter calling on the FDA to strengthen enforcement against the mass production and marketing of non-FDA-approved compounded products.
“GLP-1 drugs have transformed care for people living with obesity and related chronic conditions, offering new hope for millions managing a lifelong disease. But as demand for these therapies has grown, so too has a parallel market of large-scale compounded products, raising urgent questions about safety, transparency, and oversight.
Recent reports identifying impurities in compounded versions of tirzepatide that include vitamin B12 underscore these concerns. While compounding can play an appropriate role when used to meet the specific needs of an individual patient, the large-scale production and marketing of compounded versions of these medicines raises serious safety risks when products have not undergone the rigorous scientific and regulatory review required for FDA-approved therapies. The addition of vitamins and minerals under the guise of personalization are not only a sham, but may have harmful effects, such as those found when ingredients interact and form byproducts that are not tested for safety.
People living with obesity should not have to question whether their medication is safe, legitimate, or held to consistent standards. Protecting patients means strengthening oversight, improving transparency, and ensuring that access to treatment never comes at the expense of safety.
The Obesity Society supports efforts to protect patients and ensure the integrity of the medication supply, including removing dangerous compounded versions of these life-saving treatments from the market. We also call on the FDA to take action against companies that mass-produce or mass-market, either online or in-person, unapproved products as substitutes for FDA-approved medicines.
TOS remains committed to advancing science-based, patient-centered policies and encourages policymakers to continue engaging on common-sense solutions that prioritize patient safety while preserving appropriate clinical care.”
About The Obesity Society (TOS)
The Obesity Society (TOS) is the leading scientific organization dedicated to advancing the understanding, prevention, and treatment of obesity. Through research, education, and evidence-based advocacy, TOS promotes a comprehensive and science-driven approach to addressing obesity as a serious, chronic, and treatable disease. The Society’s members include scientists, clinicians, policymakers, and other professionals working to improve health outcomes and reduce the global impact of obesity. Learn more at www.obesity.org.