Mounjaro contains tirzepatide, a prescription medicine used alongside a reduced-calorie diet and increased physical activity to support weight loss and weight maintenance in eligible adults. It works on two hormone pathways involved in appetite and blood sugar regulation, helping increase feelings of fullness while reducing hunger and food cravings.
Mounjaro is the brand name for tirzepatide, a prescription medicine manufactured by Eli Lilly. It is a dual GIP and GLP-1 receptor agonist, meaning it acts on two hormone pathways involved in appetite regulation, food intake and blood glucose control.
For weight management, Mounjaro is licensed in the UK for adults with an initial BMI of 30 kg/m² or above, or adults with a BMI of 27 kg/m² to less than 30 kg/m² who also have at least one weight-related health problem, such as high blood pressure, abnormal blood fats, obstructive sleep apnoea, cardiovascular disease, prediabetes or type 2 diabetes. It is intended to be used alongside a reduced-calorie diet and increased physical activity.
There is an important distinction between being licensed to use Mounjaro for weight management and being eligible to receive it through the NHS in England. NICE currently recommends NHS-funded tirzepatide for adults with an initial BMI of at least 35 kg/m² and at least one weight-related comorbidity, with lower BMI thresholds usually applying to certain ethnic groups. NHS access is also being introduced in phases.
Dr Frank's offers Mounjaro through a private prescription pathway. Its current website states that patients complete an online assessment before a specialist nurse reviews eligibility, with medication prescribed through its GPhC-registered partner pharmacy.
For women in perimenopause or menopause, weight management can become more challenging as body composition and fat distribution change. There is emerging evidence specifically examining tirzepatide in women at different reproductive stages, but Mounjaro should not be regarded as a treatment for menopause itself. A post-hoc analysis of SURMOUNT trials found substantial weight reductions among premenopausal, perimenopausal and postmenopausal women treated with tirzepatide, although this was an analysis of existing trial data rather than a trial designed specifically to treat menopause-related weight gain.
Mounjaro is administered as a once-weekly subcutaneous injection.
Treatment normally begins with a low dose, which is gradually increased to help the body adjust and to balance potential benefits with side effects. The current product information describes an initial 2.5 mg dose for four weeks, followed by 5 mg once weekly. Further increases can be made in 2.5 mg increments after at least four weeks on the current dose, depending on individual response and tolerability.
The recommended maximum dose is 15 mg once weekly. Make dose changes according to the prescribing clinician's instructions rather than adjusting them independently.
If a weekly dose is missed, the product information states that it can be administered within four days of the scheduled dose. If more than four days have passed, skip the missed dose and take the next dose on the usual day.
Use Mounjaro alongside dietary and physical-activity changes. It is not intended to replace a balanced diet, adequate nutrition or regular movement.
Your prescribing clinician or pharmacist should provide specific instructions on injection technique, storage and disposal. Do not change the dose, injection schedule or treatment plan without professional advice.
One of the earliest changes some people notice is reduced hunger and fewer food cravings. The product information describes increased feelings of fullness, reduced hunger and reduced food cravings as part of how tirzepatide supports weight loss.
Weight loss is generally gradual rather than immediate. Dr Frank's states that many patients begin noticing changes within the first few weeks, while clinical trial evidence demonstrates weight reduction over a considerably longer period.
In the 72-week SURMOUNT-1 trial cited by Dr Frank's, participants receiving tirzepatide achieved substantial average weight reduction, with the highest-dose group achieving up to 22.5% body-weight loss. This was in the context of the clinical trial programme and lifestyle intervention, and should not be interpreted as a guarantee of an individual's result.
The first weeks can also involve unwanted effects, particularly nausea, diarrhoea, constipation or vomiting. These are more common while the dose is being increased and often become less troublesome over time.
It is also important to think beyond the scales. Weight management treatment works best as part of a longer-term approach that includes adequate nutrition, physical activity and sustainable habits. NICE specifically recommends combining tirzepatide with a reduced-calorie diet and increased physical activity.
Results vary between individuals. Mounjaro is a treatment, not a guarantee of a specific amount of weight loss, and it should not be used for cosmetic or aesthetic weight loss by someone who does not meet the medical criteria.
Mounjaro's active ingredient is tirzepatide. The medicine works by activating GIP and GLP-1 receptors. These pathways influence appetite, satiety, food intake and glucose regulation. Tirzepatide also delays gastric emptying, particularly early in treatment, which can contribute to its effects on appetite and post-meal glucose levels.
The current KwikPen formulation also contains inactive ingredients, including benzyl alcohol. The exact formulation should be checked against the patient information leaflet supplied with the prescribed pen.
The most frequently reported side effects are gastrointestinal. These include:
In weight-management trials, gastrointestinal side effects occurred more frequently with tirzepatide than placebo and were particularly common during dose escalation. They were generally mild to moderate and tended to reduce over time.
Dehydration can occur if vomiting or diarrhoea is significant. Drink enough fluids, and discuss persistent vomiting or diarrhoea with a healthcare professional.
Mounjaro is not suitable for everyone. The patient information leaflet states that it should not be used by anyone with a known allergy to tirzepatide or any of its ingredients. People with severe problems affecting stomach emptying, including severe gastroparesis, should discuss this carefully with their prescriber.
Pancreatitis is an uncommon but potentially serious complication associated with medicines in this class. Severe, persistent abdominal pain, particularly if it radiates through to the back, requires urgent medical assessment.
Gallbladder problems, including gallstones and inflammation of the gallbladder, have also been reported in people using tirzepatide.
Mounjaro can also affect the absorption of some oral medicines because it delays gastric emptying. This is particularly relevant to contraception.
This is especially important for women of perimenopausal age.
If you take the combined oral contraceptive pill or another oral hormonal contraceptive, tirzepatide can reduce contraceptive reliability because it may affect absorption. UK guidance recommends using an additional barrier method for four weeks after starting Mounjaro and for four weeks after each dose increase, or discussing a non-oral contraceptive option with a healthcare professional.
If you use oral HRT, discuss this with your clinician as well. NHS England advises that women using tirzepatide and HRT should consider transdermal HRT, such as patches or gels, because absorption of oral HRT may be affected.
Mounjaro should not be used during pregnancy. Current UK guidance also advises against using GLP-1 medicines while trying to become pregnant or while breastfeeding. Tirzepatide should be stopped at least one month before a planned pregnancy.
Tell your healthcare team if you are taking Mounjaro before undergoing surgery or another procedure, including when an anaesthetic may be required.
Mounjaro is worth considering as a medically supervised weight-management option because substantial clinical evidence supports its use and it has a UK marketing authorisation for weight management in appropriately selected adults. NICE has also recommended tirzepatide as an option for managing overweight and obesity within specified NHS eligibility criteria.
The medicine works differently from traditional weight-loss approaches. Tirzepatide acts on both GIP and GLP-1 receptors and clinical studies show that it can reduce appetite, hunger and food cravings while supporting substantial weight reduction when combined with dietary and physical-activity changes.
Dr Frank's provides a private prescribing pathway with an online assessment and specialist nurse review. Its current programme also offers clinician-led options with monthly nurse reviews, dose-adjustment guidance and support with side effects.
Emerging evidence is particularly interesting for women in midlife. A post-hoc analysis of the SURMOUNT programme found significant weight reductions with tirzepatide among women who were premenopausal, perimenopausal and postmenopausal. However, this does not establish Mounjaro as a menopause treatment, and individual results can vary considerably.
The key reason to consider Mounjaro is therefore not simply the potential number on the scales. It is a prescription medicine with evidence for weight management that may form part of a wider, medically supervised approach for people who meet the appropriate criteria.
The UK marketing authorisation covers adults with a BMI of 30 kg/m² or above, or adults with a BMI of 27 kg/m² to less than 30 kg/m² who also have at least one weight-related health condition. Private providers will have their own clinical assessment process. NHS prescribing is subject to additional NICE and NHS England eligibility criteria.
Mounjaro is normally injected once a week. Treatment starts at a low dose and can be increased gradually according to the prescribing clinician's instructions and how well you tolerate it.
Some people notice reduced hunger or appetite changes during the first few weeks, but meaningful weight loss is a longer-term process. Clinical trials assessed weight reduction over many months, rather than expecting a particular result after only a few weeks.
Being perimenopausal or postmenopausal does not automatically prevent someone from using Mounjaro. Emerging analysis of clinical-trial data found substantial weight reductions among premenopausal, perimenopausal and postmenopausal women treated with tirzepatide. However, Mounjaro is a weight-management medicine, not a treatment for menopause itself.
Discuss this with your healthcare professional. NHS England advises that women using tirzepatide alongside HRT should consider patches or gels rather than oral HRT because tirzepatide may affect absorption of oral medicines.
Yes. Tirzepatide can affect absorption of oral contraception. UK guidance recommends additional barrier contraception for four weeks after starting Mounjaro and for four weeks following each dose increase, or consideration of a non-oral contraceptive method.
The most common side effects involve the digestive system, particularly nausea, diarrhoea, vomiting and other gastrointestinal symptoms. They tend to be more common during dose escalation. Serious complications are uncommon, but severe persistent abdominal pain requires urgent medical assessment because it can be a sign of pancreatitis.
Mounjaro is a prescription medicine and requires an appropriate clinical assessment. Consider your BMI, existing health conditions, other medicines, contraception, HRT, pregnancy plans, previous gastrointestinal or pancreatic problems and your ability to maintain dietary and physical-activity changes alongside treatment. A qualified prescriber should assess whether the potential benefits outweigh the risks for you.
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