How much protein should I have on Mounjaro?

What the SURMOUNT-1 trial reveals about weight loss and muscle loss

The SURMOUNT-1 trial, published in the New England Journal of Medicine, followed more than 2,500 adults over 72 weeks. At the highest tirzepatide dose, participants lost around 20–21% of their body weight on average. That is a remarkable result, but it carries a practical implication that does not always make the headlines. In any large calorie deficit, the body draws on both fat stores and lean tissue. The lower your protein intake, the greater the share of that lean tissue you risk losing.

NICE's appraisal of tirzepatide (TA1026) and the NHS England guidance on weight-management injections both emphasise that these medicines work best alongside dietary support and increased activity, not purely as an appetite suppressant. Protein sits at the centre of that support. It is the most satiating macronutrient, so adequate intake also helps on days when appetite returns briefly between doses.

A practical checking habit worth building: read the protein content on the back of whatever you are having for lunch. Aim for at least 20–30 g per meal. That one-minute label check, done daily, gives you a running sense of whether you are on track without any tracking app.

Our full guidance on how much protein to eat on Mounjaro goes deeper on the daily totals by body weight, if you want the numbers broken down further.

What a realistic daily protein target looks like, and what affects yours

The 1.2–1.6 g per kilogram figure comes from exercise-science and clinical-nutrition literature on preserving muscle during weight loss. For a 90 kg adult, that is 108–144 g of protein per day. For an 80 kg adult, 96–128 g. Those are not arbitrary numbers: they reflect the intake at which most studies show meaningful muscle retention during an energy deficit. If you want to understand how much protein per day on Mounjaro is right for your situation, our dedicated page walks through what the evidence suggests for different body weights and activity levels. Some clinicians advise going toward the higher end of that range during the active weight-loss phase on GLP-1 treatment.

Several factors shift where in that range you should sit. Activity level matters, people doing resistance training regularly tend to need more. Age matters too, because muscle synthesis becomes less efficient in older adults. If you are unsure how much protein you personally need on Mounjaro, factors such as kidney function are especially worth discussing with a clinician, since anyone with existing kidney disease should have their protein target set by a professional rather than a general guideline. The NHS tirzepatide medicines page recommends involving your healthcare team in decisions about diet alongside treatment, which is the right starting point.

There is a separate page covering how much protein you should eat on Mounjaro, including how to spread intake across meals to maximise absorption, if you want a closer look at the practical maths.

How treatment cost fits into planning your nutrition on Mounjaro

Private Mounjaro treatment in the UK is priced per pen, per month. Since Eli Lilly raised the list price from 1 September 2025 (reported figures put the highest-dose pen's list price at around £330) typical private prices across providers have ranged roughly £149–£375 a month depending on dose and service. That range is widely reported and should be taken as market context, not a quote for any specific provider.

What matters, and what people searching for the cheapest option sometimes overlook, is what a headline price includes. A prescription fee charged separately, no aftercare when nausea hits at week three, and a delivery charge on top can close a price gap quickly. At nume, we do not compete on being the lowest number you will find. One price covers the consultation, the prescription, the medicine, and next-day delivery, with seven-day aftercare included. That is a deliberate choice. You can read more about how Mounjaro pricing works in the UK and what the monthly cost typically reflects.

For anyone working out whether private treatment fits their budget alongside a proper diet, the weight-loss treatment overview sets out the full picture of what is available and how each option works.

Why 'cheapest' is the wrong question when sourcing a prescription medicine

Mounjaro is a Prescription-Only Medicine. That legal classification exists because the medicine requires clinical assessment before it is issued, not as a formality, but because several conditions and medicines interact with it, and dose increases need monitoring. Sellers offering tirzepatide without a prescription, at prices well below market, or via social-media channels are a documented problem: the MHRA has seized counterfeit weight-loss pens in large numbers and issued repeated public warnings about fake products found to contain insulin rather than the labelled medicine.

Price is genuinely the wrong test for a prescription medicine. The right questions are: is this pharmacy registered with the GPhC, is a qualified prescriber reviewing my case, and is the medicine coming from the licensed UK supply chain? You can verify any online pharmacy at the GPhC register; our registration number is 9012878. Every repeat order at nume is reviewed by a prescriber before dispatch, not auto-renewed, not rubber-stamped. If you are travelling and want to understand how much Mounjaro costs in Lanzarote compared with continuing your UK prescription, our clinical team can help you plan ahead. If you want to talk through your treatment, protein targets and all, our clinical team is the place to start.

Ready to get started? Speak to our prescribers through a free consultation, it takes a few minutes, and a real clinician reviews your answers the same day.