Supplements to Take With Mounjaro: UK Guide (October 2026)

01 · The short answer

Which supplements are worth considering?

No supplement is required with Mounjaro, but eating much less can leave gaps, so a standard daily multivitamin is a reasonable safety net while losing weight.¹ Anything beyond that is a conversation for a pharmacist, who knows your other medicines and conditions.

You will see long lists online: protein powders, fibre, vitamin D, B12, magnesium, collagen. Dosing for these is not standardised, and the right choice depends on your diet and health. Our guides on supplements to take while on Mounjaro and supplements and side effects go further.

02 · Making treatment work

How to make Mounjaro work better

Diet, protein, movement and fluids do more than any supplement. Mounjaro is licensed for use alongside a reduced-calorie diet and increased physical activity.¹ In SURMOUNT-1, people on 5mg lost on average 15% of body weight, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, against 3.1% with lifestyle changes alone. These are trial averages and individual results vary.²

For someone starting at 100 kg, 20.9% is about 21 kg. Your own result depends on dose, diet and activity. If you are not yet treated, see the Mounjaro pen or start your free consultation; the pen is in stock across all six doses.

03 · Protein and muscle

Protein and muscle preservation

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 and resistance exercise two or more times a week.

Aim to include a protein source at every meal, which is harder when appetite is low. This matters more, not less, as the dose rises and appetite falls. Shakes are one way to hit that target if food alone is difficult, but they are a convenience, not a requirement.

04 · Fluids and fibre

Hydration, fibre and digestion

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.

Keep water within reach through the day. If you cannot keep fluids down, contact your clinical team — dehydration needs medical help straight away. For food, prioritise vegetables and fibre alongside protein and regular fluids.

05 · What to avoid

Supplements and foods to avoid

Avoid anything sold as a "natural GLP-1 booster". These are not equivalents and are not substitutes for prescribed treatment. Be sceptical of dramatic weight-loss claims; see our guide on whether you can take GLP-1 supplements.

No food is banned on Mounjaro, including bananas, and chocolate is not forbidden. But 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. Alcohol has no direct interaction, but it hits harder on an emptier stomach and adds calories.

06 · Best time to inject

When should you take Mounjaro?

Mounjaro is a once-weekly injection, so choose whichever day suits you and is easy to repeat. Follow your prescriber's and the pen leaflet's instructions.¹³

Our guides cover the best time to inject Mounjaro and the best time of day in more detail. On injection days with early side effects, lighter movement still counts.

07 · Absorption and caffeine

Absorption, coffee and other practical points

Oral supplements, like other oral products, may be absorbed more slowly when you start treatment.¹ That is one more reason to ask a pharmacist before adding to a multivitamin.

Coffee and tea are fine. Strong coffee on an empty, slower-emptying stomach can aggravate nausea or reflux for some people, and high-calorie coffee drinks are an easy place for the calorie deficit to leak. "Coffee rules" on social media have no clinical basis.

08 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. 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. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹