Best Vitamins to Take With Mounjaro (November 2026)

01 · The core answer

What vitamins should you take while on Mounjaro?

The honest answer is that there is no single best vitamin for everyone on Mounjaro. No supplement is required with treatment. The reason people think about vitamins at all is practical: Mounjaro reduces appetite, so you eat less, and eating much less can leave nutritional gaps.¹

That is why a standard daily multivitamin is a reasonable safety net while you lose weight. It is low-cost, widely available from any pharmacy, and does not require you to work out which individual nutrient you might be short of. A plain, balanced A-to-Z style product is enough. You do not need a premium "GLP-1 formula", and you do not need a stack of separate pills.

If you are tempted to go beyond a multivitamin, such as adding single vitamins, minerals, collagen or powders, discuss it with a pharmacist first.

02 · Your next step

What should you actually do next?

Start with food, add a plain multivitamin if your appetite has dropped a lot, and raise any other supplement idea with a pharmacist or your prescriber. If you are not yet on treatment, our weight loss clinic explains how a free online consultation works, and the Mounjaro pen page shows current availability and pricing.

For wider reading, our guide on what to take alongside Mounjaro covers the practical routine beyond supplements, and vitamins on GLP-1 medicines covers the wider class.

03 · Why gaps can appear

Why eating less can leave gaps

Mounjaro contains tirzepatide, which activates two natural gut-hormone receptors, GIP and GLP-1. Together these help regulate appetite and slow how quickly the stomach empties. In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.¹

That is the intended effect, but it has a side consequence. When you eat much less, there is less variety on the plate, and smaller amounts of food carry smaller amounts of every nutrient. This is the reason a multivitamin is described as a safety net rather than a treatment.

It is also worth knowing that the dose rises over time. Appetite often falls further as the dose increases, so a gap that was small on the starter pen may matter more later. Keep an eye on how much and how varied your eating really is, rather than assuming it stays the same.

If you are not sure whether your intake is adequate, a pharmacist or your prescribing team can talk it through at a monthly review. Ongoing monthly reviews are included with treatment through us.

04 · Choosing a multivitamin

How to choose a multivitamin

Choose a standard, balanced daily multivitamin from a pharmacy or a mainstream retailer. That is the specific product type described as a reasonable safety net while losing weight.¹ The point is simplicity, not sophistication.

• Keep it plain. A general A-to-Z style product covers broad ground without you having to guess which single nutrient matters.
• Ignore weight-loss branding. Labels promising to "boost" or "mimic" GLP-1 are marketing. They are not equivalents of the medicine.
• Follow the packet. Use the product as the label directs. Dosing is not standardised across products, so check with a pharmacist.
• Tell a pharmacist. If you take other medicines, a quick check costs nothing and avoids surprises.

If you have been told before that you are short of a particular nutrient, mention it to your prescriber when you start treatment. That history matters more than any generic list.

05 · Absorption and timing

Do vitamins absorb differently on Mounjaro?

Oral supplements, like other oral products, may be absorbed more slowly when you start treatment.¹ The mechanism is the slower stomach emptying that is part of how the medicine works.

In practical terms, this is a reason to be patient and consistent rather than to take more. A slower start to absorption is not a signal to increase the amount you take. It is also a reason to tell your prescriber or pharmacist about everything you take by mouth, including anything you buy over the counter, so they can factor it in.

The same slower emptying is why some oral medicines need extra thought. For example, the medicine can reduce absorption of oral contraceptives. The SmPC advises switching to a non-oral method, or adding a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.¹ Supplements are lower stakes, but the principle of telling your clinical team everything is the same.

If a tablet or capsule makes you feel nauseous on an empty stomach, taking it with a meal is a common-sense approach, and a pharmacist can confirm what suits the specific product you have chosen.

06 · Food first

Food first: what does more than a supplement

No food is banned on Mounjaro, including bananas, but some choices make treatment easier and more effective. Prioritise protein at each meal, vegetables and fibre, and regular fluids.¹

Many people feel worse after very fatty, fried or very sugary food, and large portions sit heavily because the stomach empties more slowly. Smaller, slower meals work better. Treatment is licensed alongside a reduced-calorie diet, so the aim is a sustainable deficit, not a perfect food list.

This is a good reason to put food before pills. A varied plate delivers nutrients in combination, and it keeps you fuller. If appetite is low, make each small meal count: a protein source, some vegetables, and something with fibre.

Our week-by-week guide to supplements while on Mounjaro shows how this fits into the weeks of titration.

07 · Protein and muscle

Protein, muscle and why it matters more than vitamins

Some of any rapid weight loss comes from lean tissue, and protecting muscle protects your metabolism, strength and appearance. The two levers are adequate protein — aim to include a protein source at every meal, which is harder when appetite is low — and resistance exercise two or more times a week.¹

This matters more, not less, as the dose rises and appetite falls. If you are going to spend effort on any part of your routine, this is the place. A capsule cannot replace eating protein or training your muscles.

Exercise is also part of the licence rather than an optional extra. Nothing special is required: regular moderate activity such as brisk walking, plus resistance work for muscle. Start where you are and build. On injection days with early side effects, lighter movement still counts. Exercise also protects against regain if you later stop treatment.¹

08 · Hydration

Hydration: the one daily habit that is not optional

Drinking enough matters more on Mounjaro than usual. Reduced appetite means less fluid from food, and vomiting or diarrhoea can dehydrate you quickly, which is the main route to the rare kidney problems reported with this class.¹

Keep water within reach through the day. If you cannot keep fluids down, treat it as a contact-your-clinical-team issue, not something to push through. No supplement makes up for this.

Tea and coffee are fine, since there is no interaction between Mounjaro and caffeine. Strong coffee on an empty stomach can aggravate nausea or reflux for some people, and high-calorie coffee drinks are an easy place for the calorie deficit to leak.¹

09 · Collagen and extras

What about collagen, probiotics and other extras?

Collagen is a popular add-on, but it is not required for Mounjaro treatment.

Weight loss on treatment comes from the medicine working alongside a reduced-calorie diet and increased physical activity. A supplement is not a substitute for any of those. For an authoritative view on collagen, check with a pharmacist or the NHS website.

Common downsides of any extra product are practical ones: cost, tablet fatigue, and the temptation to treat it as a shortcut. If you do choose a product, keep it low-cost, tell your pharmacist, and do not let it displace protein from real food.

Gut-focused products are a separate question. Our guide to the probiotic to take while on Mounjaro looks at gut-focused products.

10 · What to avoid buying

Supplements and claims to be careful with

Be sceptical of anything marketed as a "natural GLP-1 booster", "nature's Ozempic" or similar. These are not equivalents of prescribed treatment and are not substitutes for it.¹ They are low-cost supplements with no clinical oversight, and dramatic weight-loss claims attached to them should be treated as marketing.

Be equally careful with sources of Mounjaro itself. Genuine medicine comes through a regulated pharmacy after a consultation. Anyone offering to supply without a consultation or prescription is a warning sign, and counterfeit medicine alerts are published by the MHRA.⁷ You can check any pharmacy on the GPhC register; ours is GPhC 9012878.

For specific combinations with other medicines, see our guide on vitamins not to take with Mounjaro. If you take insulin or a sulfonylurea, your doses may need adjusting because of low blood sugar risk, and your prescriber is the right person to manage that.

11 · When to speak to someone

When to speak to a pharmacist or prescriber

Speak to a pharmacist before adding any supplement beyond a standard multivitamin.¹ Speak to your prescribing team if you cannot keep fluids down, if you are eating very little, or if a new symptom appears after you start a supplement.

If you notice a symptom you think could be a side effect, you can report it through the Yellow Card scheme.¹⁹ Seek immediate medical help for severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. Support is available Monday to Friday, 9am to 5pm, on 0333 207 0413 or at support@everydaymeds.co.uk, and ongoing monthly reviews are part of treatment.

Mounjaro is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. It is used alongside a reduced-calorie diet and increased physical activity. Individual results vary. This page is information, not a substitute for medical advice. For more on this topic, see how vitamins fit with Mounjaro, tips to maximise results and the complete UK vitamins guide.