Compounded semaglutide or compounded tirzepatide with B12 (cyanocobalamin): what it means

What does "semaglutide/cyanocobalamin" or "tirzepatide with B12" mean on a vial?

A vial labeled "semaglutide/cyanocobalamin," "tirzepatide/cyanocobalamin," "semaglutide with B12" or "tirzepatide with B12" holds a compounded medication: a compounding pharmacy has combined the GLP-1 medication and vitamin B12 in one vial. Cyanocobalamin is one form of vitamin B12; some labels name other forms, such as methylcobalamin or hydroxocobalamin. The numbers after the name are concentrations, usually in milligrams per milliliter, listed in the same order as the ingredients. Your prescription and the pharmacy's directions tell you how much to inject; don't work out a dose from the label on your own.

Cyanocobalamin is red. The DailyMed label for cyanocobalamin injection describes it as a "clear dark red" solution, which is why a vial that contains it can look pink or red. Read the label rather than going by color, and ask your pharmacy if a refill looks different from your last one.

No compounded medication, with or without an added ingredient, is a version of Ozempic, Wegovy or Zepbound; the FDA labels for those products list no vitamin B12 among their ingredients. Compounded medications are not FDA-approved and are not therapeutically equivalent to FDA-approved products.

What other additives are in compounded semaglutide and compounded tirzepatide?

Compounding pharmacies also prepare compounded semaglutide or compounded tirzepatide with other added ingredients, and some vials contain more than one:

• Vitamin B6 (pyridoxine): labels read, for example, "tirzepatide/pyridoxine" or "tirzepatide with B6."
• Glycine: an amino acid, as in "semaglutide/glycine."
• Niacinamide: a form of vitamin B3, as in the compounded tirzepatide/niacinamide products named in FDA's September 18, 2026 warning letter to Empower Pharmacy.
• Two additives in one vial: for example, compounded semaglutide with glycine and B12.

These products are common. A 2026 review in Annals of Pharmacotherapy searched compounding websites in February and March 2025 and found 33 compounded semaglutide or compounded tirzepatide products that differed from FDA-approved products; 48% combined the GLP-1 with cyanocobalamin, glycine, niacinamide, docusate or ondansetron. Compounded medications, including these combinations, are not FDA-approved and are not therapeutically equivalent to FDA-approved products.

Does adding B12, B6 or glycine to compounded semaglutide or compounded tirzepatide do anything?

No clinical trial has tested it. A search of ClinicalTrials.gov on September 27, 2026 found no registered trial of compounded semaglutide or compounded tirzepatide combined with vitamin B12, vitamin B6 or glycine in one product. The only published patient study of a B12 combination that Cora Health found is a retrospective review of 94 people who used compounded semaglutide/cyanocobalamin at a commercial wellness program (Diabetes, Obesity and Metabolism, 2025). It had no comparison group, so it cannot show whether the B12 made any difference.

A 2026 review in Annals of Pharmacotherapy found "little justification for adding nutrients" to injected compounded semaglutide or compounded tirzepatide products, concluded that "it is unclear what advantages adding 1 or 2 nutrients to these products provide patients," and found no patient data on glycine used with either medication. Eli Lilly, which makes Mounjaro and Zepbound, says "tirzepatide has never been studied in combination with B12." Compounded medications are not FDA-approved and are not therapeutically equivalent to FDA-approved products.

What did FDA say about compounded semaglutide/cyanocobalamin in September 2026?

On September 18, 2026, FDA sent a warning letter to Empower Pharmacy, a compounding pharmacy in Houston, Texas, and posted it on fda.gov on September 22, 2026. The letter follows a November 2025 inspection and names three compounded products, SEMAGLUTIDE/CYANOCOBALAMIN and two strengths of TIRZEPATIDE/NIACINAMIDE, "which appear to be essentially copies of FDA-approved semaglutide and tirzepatide products" (a legal test under section 503A, not a finding that they are the same drug). FDA wrote: "The volume of products you are producing suggests that differences between products you are compounding and the FDA-approved products are pretextual."

FDA also described the prescriptions behind those orders. Some had no prescriber determination of a "significant difference" at all. Others carried purported determinations that "appear to be repeated verbatim across many records, suggesting that they may be pre-generated for selection by the prescriber, rather than written by the prescriber for an identified individual patient." The letter says prescriptions generated "through third-party technology platforms that provide prescribers with pre-selected menu options for choosing a statement of significant difference" call the individualized nature of those determinations into question. It also cites insanitary conditions and manufacturing-practice violations that investigators observed at the facility.

FDA had already published a related position. FDA's compounding policy page, updated April 1, 2026, says FDA "may consider a compounded drug product that combines semaglutide API and another API, such as vitamin B12 (cyanocobalamin), to be essentially a copy" of a commercially available drug when it is given the same way, for example by injection, and its strengths are within 10% of the commercially available products, unless a prescriber documents a change that produces a significant difference for an identified individual patient. Compounded medications are not FDA-approved and are not therapeutically equivalent to FDA-approved products.

What "essentially a copy" means, and what it doesn't

"Essentially a copy" is a legal test in section 503A of the Federal Food, Drug, and Cosmetic Act, which sets the conditions for compounding by state-licensed pharmacies. Under it, a 503A pharmacy may not compound, regularly or in inordinate amounts, drugs that are essentially copies of a commercially available drug. The law says a compounded drug is not essentially a copy if "there is a change, made for an identified individual patient, which produces for that patient a significant difference, as determined by the prescribing practitioner." According to the Empower letter, FDA's shortage-era enforcement discretion for state-licensed pharmacies ended on March 5, 2025 for compounded tirzepatide injections and on April 24, 2025 for compounded semaglutide injections.

The phrase does not mean a compounded drug is the same as, or interchangeable with, an FDA-approved drug. Compounded medications are not FDA-approved and are not therapeutically equivalent to FDA-approved products.

What did Eli Lilly say about compounded tirzepatide with B12?

On March 12, 2026, Eli Lilly and Company, which makes the FDA-approved tirzepatide medicines Mounjaro and Zepbound, published an open letter about compounded tirzepatide mixed with vitamin B12. Lilly said its testing of these products "uncovered significant levels of an impurity that results from a chemical reaction between tirzepatide and B12," and that "nothing is known about its short- or long-term effects in humans," including its toxicity. Lilly said it had notified FDA. Lilly published its testing in Expert Opinion on Drug Safety (2026), describing samples "obtained from various sources in the U.S. market" and stating that the impurity's clinical effects are unknown.

These are a drug manufacturer's findings about compounded products that compete with its own. The Alliance for Pharmacy Compounding (APC), a trade group for compounding pharmacies, responded that Lilly had not said where its samples came from or how they were handled, and wrote that "patient safety deserves evidence, not insinuation." Cora Health has not independently verified either side's claims. Lilly's letter and paper concern compounded tirzepatide with B12. They do not say whether the same reaction occurs in compounded semaglutide with B12. Compounded medications are not FDA-approved and are not therapeutically equivalent to FDA-approved products.

My vial says "semaglutide/cyanocobalamin" or "tirzepatide with B12." What should I do?

Talk to your prescriber before you stop, switch or change your dose. FDA's September 18, 2026 warning letter is addressed to one pharmacy, Empower Pharmacy, and does not tell patients to stop their medication. Eli Lilly recommends that people using compounded tirzepatide with B12 "contact their physicians for advice and discussion on alternative treatment options." Bring these questions to your prescriber:

• Which pharmacy prepared my medication? Its name is on the vial label.
• What exactly is in my vial, and why was an additive included?
• Is a version without an additive available to me, and would switching change my dose?
• After FDA's letter and Lilly's report, should anything about my treatment change?

Tell your provider about any side effects. You can also report them to FDA's MedWatch program at 1-800-FDA-1088 or fda.gov/medwatch. Compounded medications are not FDA-approved and are not therapeutically equivalent to FDA-approved products.

How to evaluate a provider of compounded semaglutide or compounded tirzepatide

Whichever provider you use, these are facts you can check before you start compounded semaglutide or compounded tirzepatide, with or without an added ingredient:

• A licensed prescriber who evaluates you. A licensed provider should review your health history before prescribing, and you should be able to find the prescriber's name. You can look a clinician up in the NPI Registry and confirm the license with the state medical board.
• A named compounding pharmacy you can look up. The provider's website, or at the latest your vial label, should name the pharmacy that prepares your medication. A 503A pharmacy compounds for individual patients with valid prescriptions and is licensed by state boards of pharmacy, where you can check its license.
• A transparent, all-in price. The price should say what it includes, such as the consultation, the medication and shipping; how much is billed and how often; and whether the plan renews automatically.
• An exact formulation. The label should list each active ingredient and its concentration, including any added ingredient, so you and your prescriber know what you are taking.

Compounded medications are not FDA-approved and are not therapeutically equivalent to FDA-approved products.

FAQ: compounded semaglutide and compounded tirzepatide with B12

Is compounded semaglutide or compounded tirzepatide with B12 the same as Ozempic, Wegovy, Mounjaro or Zepbound? No. No compounded semaglutide or compounded tirzepatide, with or without B12, is the same as these FDA-approved products. Ozempic and Wegovy (Novo Nordisk) and Mounjaro and Zepbound (Eli Lilly) are FDA-approved, and the FDA labels for Ozempic, Wegovy and Zepbound list no vitamin B12. Compounded medications are not FDA-approved and are not therapeutically equivalent to FDA-approved products, and FDA has said companies cannot claim that compounded drugs are generic versions of, or the same as, FDA-approved drugs.

Why is my compounded semaglutide or compounded tirzepatide pink? If the label lists cyanocobalamin or another form of vitamin B12, the vitamin is the likely reason: cyanocobalamin is red, and cyanocobalamin injection is a "clear dark red" solution. Color alone can't tell you what is in a vial. Read the label, and ask your pharmacy if a refill looks different from your last one. Compounded medications are not FDA-approved.

How much vitamin B12 should I take with compounded semaglutide or compounded tirzepatide? There is no one answer: nutrient needs differ from person to person, and no trial has tested adding B12 to either medication. A 2025 joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society recommends "re-assessment of nutrient levels" during GLP-1 treatment to identify and address deficiencies. If you are concerned about your B12 level, ask your provider whether a blood test makes sense, and tell your provider and pharmacist about every vitamin or supplement you take. Compounded medications are not FDA-approved.

Is compounded semaglutide with B12 going away? No one can say. On February 6, 2026, FDA said it intends to restrict GLP-1 active ingredients used in non-FDA-approved compounded drugs that are mass-marketed as similar alternatives to FDA-approved drugs. As of September 27, 2026, FDA has not announced a rule banning compounded semaglutide or compounded tirzepatide with B12. Its September 18, 2026 warning letter went to one pharmacy, and its compounding policy page says it may treat a compounded semaglutide and B12 combination given the same way and at similar strengths as essentially a copy of a commercially available drug, unless a prescriber documents a significant difference for an identified patient. What pharmacies and providers offer may change; ask your provider about your options. Compounded medications are not FDA-approved.

Sources

Last verified: September 27, 2026. Regulatory actions, formulations and prices change; confirm with the source before you decide. This article is general information, not medical or legal advice. Ozempic®, Wegovy®, Mounjaro® and Zepbound® are registered trademarks of their respective owners. Cora Health is not affiliated with Novo Nordisk or Eli Lilly.

• FDA: Warning Letter 738238 to Empower Clinic Services, LLC dba Empower Pharmacy (dated September 18, 2026; posted September 22, 2026). fda.gov
• FDA: FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize (updated April 1, 2026). fda.gov
• FDA: FDA intends to take action against non-FDA-approved GLP-1 drugs (February 6, 2026). fda.gov
• Eli Lilly and Company: An open letter warning of potential patient safety risks associated with tirzepatide compounded with vitamin B12 (March 12, 2026). lilly.com
• Jordan B, et al. A novel, widespread impurity in mass-compounded tirzepatide/B12 products: potential patient safety implications. Expert Opinion on Drug Safety. 2026. Authors from Eli Lilly and Company. tandfonline.com
• Alliance for Pharmacy Compounding: Lilly's B12 "bombshell" – or is it? (March 2026). a4pc.org
• Belcourt J, Sapowadia A, White CM. Compounded semaglutide and tirzepatide products use unique formulations but efficacy and safety largely unknown. Annals of Pharmacotherapy. 2026. journals.sagepub.com
• Chun E, et al. Weight loss and body composition after compounded semaglutide treatment in a real world setting. Diabetes, Obesity and Metabolism. 2025. pubmed.ncbi.nlm.nih.gov/39776038
• ClinicalTrials.gov: registered studies of semaglutide or tirzepatide with cyanocobalamin, methylcobalamin, vitamin B12, pyridoxine, vitamin B6 or glycine (searched September 27, 2026). clinicaltrials.gov
• Mozaffarian D, et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Obesity Pillars. 2025. pmc.ncbi.nlm.nih.gov
• NIH Office of Dietary Supplements: Vitamin B12 fact sheet for health professionals. ods.od.nih.gov
• DailyMed: cyanocobalamin injection, USP 1,000 mcg/mL (checked September 27, 2026). dailymed.nlm.nih.gov
• DailyMed: prescribing information for Ozempic, Wegovy and Zepbound, section 11 ingredient lists (checked September 27, 2026).