Tirzepatide With B12: What Is in the Vial and What the Label Says

FormBlends Editorial Research. against the Zepbound and Mounjaro prescribing information and the trial publications listed under Sources.

The Zepbound and Mounjaro labels do not list vitamin B12 as an interaction, and they do not include B12 in the product. "Tirzepatide with B12" almost always means a compounded vial where a pharmacy has added a form of B12, sometimes with glycine. No trial in our verified sources has tested those combinations, so nobody can say they work better or worse than tirzepatide alone. Start with our tirzepatide guide if you are new to the drug.

Key takeaways

• Zepbound and Mounjaro contain tirzepatide only. B12 and glycine appear only in some compounded products, and the vial label should list them.
• The labels do not mention B12 as an interaction. They do say tirzepatide delays gastric emptying and may affect how oral medicines are absorbed.
• No SURMOUNT or SURPASS trial tested tirzepatide combined with B12, glycine or any other additive.
• Compounded tirzepatide with B12 is not FDA approved and is not interchangeable with Zepbound or Mounjaro.
• Whether to take a B12 supplement, and in what form, is a question for your prescriber, who can check your levels with a blood test.

Can you take B12 with tirzepatide?

The prescribing information for Zepbound and Mounjaro lists the drug interactions the manufacturer considers important. Vitamin B12 is not among them. The interactions the labels do flag are oral hormonal contraceptives (add a non-oral or barrier method for 4 weeks after starting and after each dose increase), insulin and sulfonylureas (higher risk of low blood sugar), and, in general, any oral medicine whose absorption could change because tirzepatide slows stomach emptying.

That last point is the only label-based link between tirzepatide and an oral B12 tablet: the tablet may sit in the stomach longer. The label does not say this reduces B12 absorption, and no verified source measures it, so we do not claim it does. If you already take B12 for a diagnosed deficiency, tell your prescriber you are starting tirzepatide so they can decide whether to recheck your levels.

What "tirzepatide with B12" usually means: compounded vials

When people search for tirzepatide with B12, tirzepatide methylcobalamin, tirzepatide hydroxocobalamin or tirzepatide glycine, they are usually looking at a compounded product where the pharmacy has added an ingredient to the tirzepatide solution. Here is what those names refer to.

Source: Zepbound and Mounjaro prescribing information (DailyMed), description and drug interaction sections; PubMed entries for SURMOUNT-1 and SURPASS-1 for what was tested.

The important word in that table is "No" in the last column. A pharmacy may have a reason for adding B12 or glycine, and your prescriber may agree with it, but there is no trial showing the combination changes weight loss, nausea, or anything else. Claims that B12 "boosts energy" or "reduces side effects" on tirzepatide are not backed by the sources we cite.

Tirzepatide glycine and B12: what to ask before you inject

• What exactly is in the vial? The label should list tirzepatide, its concentration, and every additive with its amount.
• Why is the additive there? Ask the prescriber, not the sales page. A licensed clinician should be able to explain the reason for your prescription.
• Does the additive change the math? The tirzepatide concentration on the label still controls your dose. At 10 mg/mL, 2.5 mg is 25 units on a U-100 insulin syringe, 5 mg is 50 units, and so on. An additive does not change that, but confirm the concentration with the pharmacy.
• Have I reacted to B12 before? Tell the prescriber about any past reaction to B12 injections or supplements before you start a combined product.
• Is the color normal? B12 gives a solution a pink or red tint. The Zepbound label describes tirzepatide alone as a clear, colorless to slightly yellow solution. A red vial means B12 is in it; a clear vial labeled "with B12" is worth a phone call. See our is tirzepatide red page.

Tirzepatide with B12 dosage

There is no labeled dose for tirzepatide with B12, because no approved product contains both. The only labeled doses are for tirzepatide itself: 2.5 mg once weekly for 4 weeks, then increases in 2.5 mg steps after at least 4 weeks on each dose, with maintenance at 5, 10 or 15 mg and a maximum of 15 mg. The amount of B12 you receive per injection is set by the compounding pharmacy's formula and appears on the label; it is not something the tirzepatide label speaks to.

Why eating less can matter for B12

B12 comes mainly from animal foods. Tirzepatide reduces appetite and food intake; in SURMOUNT-1, participants on 15 mg lost a mean 20.9% of body weight over 72 weeks, which means they ate considerably less for a long time. The trial publication we cite does not report B12 levels, so we cannot say how often deficiency happened. What we can say is that if your diet narrows a lot, a blood test is the way to know your B12 status, and a prescriber can order one. Our tirzepatide diet plan covers eating well on a smaller appetite.

What this means for compounded tirzepatide

FormBlends compounded tirzepatide is prepared by state-licensed 503A compounding pharmacies under prescriptions from independent clinicians of Recess MD LLC. The exact formula, including whether any additive is present, is on the pharmacy label that ships with your vial; read it, and ask if anything is unclear. Compounded tirzepatide is not FDA approved and is not interchangeable with Zepbound or Mounjaro. Pricing is $149 for the first month and $239 a month after that at any dose, on the pricing page; the assessment is where a clinician reviews whether it is appropriate for you.

Frequently Asked Questions

Can you take B12 with tirzepatide?

The Zepbound and Mounjaro labels do not list B12 as an interaction. If you take B12 for a deficiency, tell your prescriber you are starting tirzepatide. Whether you need a supplement at all is a question a blood test can answer.

What is tirzepatide glycine B12?

It is a compounded tirzepatide solution to which a pharmacy has added glycine, an amino acid, and a form of vitamin B12. Neither additive is in the branded product, and no trial in our verified list tested the combination.

Is compounded tirzepatide with B12 better than plain tirzepatide?

No published trial we can cite compares them, so there is no evidence either way. The tirzepatide dose is what the label and trials speak to; the B12 is an additive whose effect on results has not been measured.

What is the difference between methylcobalamin and hydroxocobalamin in tirzepatide?

They are two chemical forms of vitamin B12, alongside cyanocobalamin. A compounding pharmacy chooses which to use. No verified source compares them in combination with tirzepatide, so this page does not rank them.

What is the tirzepatide with B12 dosage?

There is no labeled combination dose. The tirzepatide dose follows the label: 2.5 mg weekly to start, then 2.5 mg steps no sooner than every 4 weeks, up to 15 mg. The B12 amount per injection is set by the pharmacy formula on your vial label.

Sources

1. Zepbound prescribing information, DailyMed, revised 08/2026.
2. Mounjaro prescribing information, DailyMed, revised 08/2026.
3. Compounding and the FDA: Questions and Answers, U.S. Food and Drug Administration.
4. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1), Jastreboff et al., New England Journal of Medicine, 2022.
5. Efficacy and safety of a novel dual GIP and GLP-1 receptor agonist tirzepatide in patients with type 2 diabetes (SURPASS-1), Rosenstock et al., Lancet, 2021.

Next steps

For how to vet the pharmacy that makes a combined product, read is compounded tirzepatide safe. Browse the tirzepatide hub for every other tirzepatide question. Talk to a licensed clinician before starting or changing any medication. Compounded tirzepatide is not FDA approved and is not interchangeable with Zepbound or Mounjaro; a licensed provider decides whether it is appropriate for you.