Why More Than 80% of Compounded GLP-1s Have Vitamins In Them
The B12 in your vial is not there for your energy levels. It is there because of a specific legal problem that appeared the moment the shortage ended.
The short version
- IQVIA reported that as of fall 2025, more than 80% of compounded semaglutide and tirzepatide prescriptions included supplemental ingredients such as B6, B12, B3, or levocarnitine.
- IQVIA researchers noted the additives may serve as a rationale for continued compounding despite the resolution of supply shortages.
- The FDA's position is that added ingredients do not by themselves justify compounding; a documented medical need for a specific patient does.
- The additive strategy also created a chemistry problem — see the March 2026 finding on a tirzepatide-B12 adduct.
Ask a compounding provider why there is B12 in your semaglutide and you will get a wellness answer: energy support, better tolerance, a metabolic assist. Ask why more than four out of five compounded prescriptions contain some additive and the wellness answer stops being plausible. Patients are not that uniform. Regulatory incentives are.
The legal problem the additive solves
Federal law lets compounders make copies of a commercially available drug under limited conditions — most importantly when that drug is in shortage. Semaglutide and tirzepatide were in shortage from 2022. When the FDA declared those shortages resolved, the copy justification disappeared.
What remained was the argument that a compounded product is not a copy at all, because it differs from the approved drug in a way that produces a clinical difference for a particular patient. Adding an ingredient creates that difference on paper. The whole personalization strategy runs on that sentence.
IQVIA reported in October that more than 80% of compounded semaglutide and tirzepatide prescriptions included supplemental ingredients such as B vitamins or levocarnitine, and wrote that these additives may serve as a rationale for continued compounding despite the FDA's resolution of supply shortages.
What the FDA has said back
The agency has not accepted the argument. Its consistent position is that you cannot simply add extras and call the product different — a real medical necessity for a specific patient has to be documented in that patient's record. In warning letters issued to telehealth companies in February 2026, the FDA also pushed back on marketing that implied compounded products had been FDA-approved or evaluated for safety and effectiveness when they had not.
The April 30, 2026 proposal to remove semaglutide, tirzepatide, and liraglutide from the 503B Bulks List is the logical continuation. If there is no clinical need for compounded versions, the additive rationale has nothing to attach to.
Does B12 actually do anything for you?
Handled honestly: B12 supplementation corrects B12 deficiency. If you have a documented deficiency, treating it is reasonable and your clinician can do that with a standalone product where the dose is known and the labelling is clear.
What B12 does not have is evidence that it improves GLP-1 outcomes, reduces GLP-1 nausea, or increases weight loss in people with normal B12 status. If your provider added it without checking your B12 level, it was not prescribed for your deficiency, because nobody established that you had one.
Providers with clear formulation disclosure
Every provider below is a paid partner. Pricing changes frequently — confirm current cost on the provider's own page before you enrol.
Marketplace for cash-pay appointments with clinicians who prescribe FDA-approved brand-name medication only — Rybelsus, the oral Wegovy pill, and Foundayo. No compounded product.
See Sesame Care pricing Paid partner linkSemaglutide injection through a licensed US telehealth network. Injectable only — no oral formulation offered.
See Embody pricing Paid partner linkOffers both injectable and sublingual/buccal compounded options. Sublingual semaglutide runs roughly $199/mo, tirzepatide roughly $299/mo.
See SkinnyRx pricing Paid partner linkThe consequence nobody priced in
A March 2026 analysis identified a tirzepatide-B12 adduct in mass-compounded tirzepatide formulated with B12 — a molecule that is not present in FDA-approved tirzepatide. Two substances dissolved together can bond into a third. That third thing has never been studied for safety or potency, because until recently nobody knew to look for it.
This is the underrated cost of the personalization strategy. It was adopted as a legal manoeuvre, executed at enormous scale, and the pharmaceutical chemistry consequences were discovered afterward.
Ask for your complete formulation in writing, including every added ingredient and its concentration. Ask whether your B12 level was tested before B12 was added. If the answer to the second question is no, ask why it is in your prescription.
Where this leaves patients
Most people taking a compounded GLP-1 with additives are fine and will stay fine. The point is not that the vitamin is hurting you. The point is that a formulation decision affecting millions of prescriptions was made for regulatory positioning rather than clinical reasoning, and the people bearing the unknown risk are the patients, not the compounders. With two approved oral GLP-1s now on the market and injectable supply stable, the tradeoff that once justified accepting that risk has largely evaporated.
Sources
- IQVIA analysis of supplemental ingredients in compounded semaglutide and tirzepatide prescriptions, October report, fall 2025 data.
- Medscape coverage of the FDA proposal to end mass GLP-1 compounding, May 1, 2026.
- US Food and Drug Administration warning letters to telehealth companies, February 2026.
- March 2026 analytical study identifying a tirzepatide-B12 adduct in compounded product.
- FDA proposed rule on 503B Bulks List status, April 30, 2026.