Key takeaways
- A peer-reviewed study in JAMA found that 92% of compounded semaglutide and 59% of compounded tirzepatide prescriptions are mixed with Vitamin B12.
- Nearly 99% of these compounded prescriptions are paid for entirely in cash, bypassing traditional insurance providers.
- The standardized use of B12 suggests pharmacies are mass-producing these coformulations rather than creating truly customized prescriptions.
- This widespread practice challenges the legal loopholes compounding pharmacies use to duplicate patented GLP-1 drugs.
What happened
A new peer-reviewed study published in JAMA (the Journal of the American Medical Association) has revealed that a vast majority of compounded glucagon-like peptide-1 (GLP-1) prescriptions are combined with cyanocobalamin, a synthetic form of Vitamin B12. Investigating dispensing records from Nebraska's comprehensive prescription drug monitoring program (PDMP), researchers found that over 90% of compounded semaglutide and nearly 60% of compounded tirzepatide prescriptions were coformulated with the vitamin.
Why it matters
For millions of cash-paying patients using telehealth platforms to access weight-loss medications, these findings raise substantial regulatory and safety questions. When a compounding pharmacy mixes a GLP-1 drug like semaglutide with Vitamin B12, the resulting coformulation is not approved by the Food and Drug Administration (FDA), nor has it undergone standard clinical trials to evaluate its combined safety or efficacy.
Compounding pharmacies frequently blend GLP-1s with B12 to support their legal defense, claiming they are creating a "customized" medication for individual patients rather than simply copying a commercially available, patented drug. However, this study proves that this "custom" formulation is actually the default setup for the vast majority of compounded GLP-1s shipped across the country, complicating the legal arguments pharmacies use to justify making these medications.
What the data says
The research team, led by Dr. Rena M. Conti and other health policy experts, analyzed real-world prescribing and dispensing patterns. Because compounded drugs are usually paid for out-of-pocket and shipped across state lines, tracking them is notoriously difficult. By leveraging Nebraska’s state-level tracking data, researchers gathered concrete numbers on how these drugs are bought and manufactured:
- Coformulation Rates: Among the compounded prescriptions analyzed, 92% of compounded semaglutide and 59% of compounded tirzepatide were mixed with Vitamin B12 (cyanocobalamin).
- Payment Methods: Nearly 99% of these prescriptions were paid for in cash, bypassing traditional insurance companies entirely.
- Out-of-State Shipments: A massive share of these medications was dispensed by pharmacies located outside of the patient’s home state, reflecting the interstate nature of modern online telehealth.
Under federal law, compounding pharmacies are permitted to make copies of FDA-approved drugs during official drug shortages. However, the high volume of standardized B12-GLP-1 combinations suggests that pharmacies may be using "customization" as a loophole to continue producing these drugs even as brand-name shortages resolve.
How it compares
In the US cash-pay market, there is a stark divide between brand-name medications and compounded alternatives. Brand-name options like Wegovy and Zepbound contain only the active peptide (semaglutide or tirzepatide) and are strictly monitored by the FDA for safety, dosage accuracy, and sterility. However, they carry steep list prices of $1,000 to $1,350 per month, pushing patients to look for more affordable options.
By contrast, compounded GLP-1 packages purchased through online providers often cost between $200 and $400 per month, as shown on our providers and compare pages. Many of these platforms partner with state-licensed compounding pharmacies that routinely ship vials of semaglutide mixed with B12. While providers often market this addition as a benefit—claiming B12 helps reduce common glp-1-side-effects like fatigue and nausea—there is little to no clinical data proving that mixing them in a single syringe is safe or effective.
Additionally, buying these mixed formulations introduces risks of dosage confusion, as patients must calculate their own active peptide dose from a combined solution.
How this fits the bigger picture
This study arrives amid a compounding legal battle between pharmaceutical giants and compounding pharmacies. Drugmakers have filed numerous lawsuits to protect their patents, as we covered in our report on how Lilly files new tirzepatide compounding lawsuits. Pharmaceutical companies argue that compounding pharmacies are producing unauthorized, unapproved copies of their drugs under the guise of "custom" medicine.
The JAMA data strongly supports the drugmakers' claims, showing that these B12 mixtures are not truly personalized for unique patient needs but are instead mass-produced, standardized formulas. This legal tension is also drawing regulatory scrutiny. We previously reported on how the FDA warns Empower Pharmacy over mass GLP-1 copies, highlighting that federal regulators are actively looking to close the compounding loopholes that telehealth networks rely on to provide cheap weight-loss options.
As these legal and regulatory pressures mount, the future availability of low-cost, compounded GLP-1 options remains highly uncertain for cash-paying US buyers.
What happens next
As the FDA continues to update its official drug shortage database, the legal status of compounded GLP-1s will shift. If brand-name shortages are fully resolved, compounding pharmacies will no longer have the legal protection to copy these drugs unless they can prove a genuine medical need for a customized formulation—such as a documented allergy to an ingredient in the brand-name version.
State boards of pharmacy and the FDA are expected to use this new JAMA data to tighten restrictions on out-of-state shipping and standardized coformulations. Cash-pay buyers should monitor these regulatory changes closely, as a sudden crackdown on compounded B12-GLP-1 blends could disrupt the supply chain for popular online weight-loss plans.
Disclaimer: CompareRx does not provide medical advice. Always consult a qualified healthcare provider before starting or changing any medication regimen.