Mounjaro (Tirzepatide)

Mounjaro works due to its active ingredient, tirzepatide, which has a dual mechanism of action as it mimics both the GLP-1 and GIP hormones in the body to aid weight loss:

Mounjaro activates GLP-1 receptors to slow down gastric emptying and promote insulin secretion when blood sugar levels are elevated. This helps with feeling fuller for longer and regulates food cravings to support weight loss.

Mounjaro also activates GIP receptors to further boost insulin secretion and improve fat metabolism, supporting weight loss.

It can take 1–2 weeks up to a few months to experience noticeable weight loss with Mounjaro, depending on factors such as the individual’s diet, lifestyle, starting weight, dosage escalation, tolerability to treatment, and how consistent they are with following the prescribed dosage schedule.

Individuals who follow the dosage schedule and maintain a balanced, calorie-restricted diet as part of a healthy lifestyle are likely to experience the desired results from using Mounjaro sooner.

If you stop taking Mounjaro, the effects of the medication on appetite control will decrease, which can cause you to regain some of the weight lost during treatment.

Mounjaro can be highly effective at aiding weight loss when used alongside a balanced diet and healthy lifestyle.

According to research, individuals can lose up to 20.9% of their body weight over 72 weeks when taking a 15mg dose of Mounjaro.

The 15mg dose is the maximum dose of Mounjaro and can be built up to by taking the starting dose of 2.5mg and gradually increasing the dosage in line with the dosage schedule and the prescriber’s instructions.

Mounjaro has been approved by the UK Medicines and Healthcare Regulatory Agency as a safe and effective weight loss medication.

To maximise the safety of Mounjaro, please read the Patient Information Leaflet before use and always follow the prescribed dosage schedule.

Mounjaro should be taken once a week at the same time each day, following the prescribed dosage escalation schedule.

You should inject Mounjaro into your upper legs, stomach (abdomen), or upper arms.

It is recommended to inject the initial starting dose of Mounjaro (2.5mg) into the stomach, as it tends to have more fat and fewer nerves, making it less uncomfortable and easier for self-administration.

Moreover, you should rotate between each of the three areas of the body each week to reduce the risk of skin irritation.

The starting dose of Mounjaro is 2.5mg once a week for four weeks.

If you take the starting dose and do not experience the side effects of the treatment, then you may be eligible to increase your dose to 5mg for weeks 5 to 8.

Thereafter, you can continue to increase the dose in line with the table below, provided you are cleared to do so by a doctor or pharmacist.

Always take Mounjaro according to the dosage schedule and instructions provided to you by the prescriber.

Mounjaro and Wegovy are two different injectable weight loss medications with differing mechanisms of action.

Wegovy contains the active ingredient semaglutide, which mimics a hormone called GLP-1 to help regulate appetite and slow down stomach emptying.

Wegovy also improves insulin sensitivity, stabilising blood glucose levels and preventing sudden spikes and crashes to prevent excessive hunger signalling by the brain.

Mounjaro contains a different active ingredient, tirzepatide, which also mimics GLP-1, in addition to mimicking another hormone known as GIP to further enhance insulin release by the body.

Mounjaro is not the same as Ozempic. While both medications can assist with weight loss, they have different mechanisms of action, active ingredients and specific dosage instructions.

Mounjaro, prescribed for weight loss, contains tirzepatide, a synthetic peptide that acts as a dual agonist for gastric inhibitory polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) receptors.

While Ozempic also contains the active ingredient semaglutide, and assists in managing blood glucose levels, it can only be used to treat type 2 diabetes, and is not currently available or licensed in the UK for weight loss.

While both treatments promote weight loss, it is important to consult with a healthcare professional to determine which medication is appropriate for your specific needs.

Orlistat is a clinically proven weight loss tablet that reduces total calorie intake by limiting the absorption of dietary fat.

In contrast, Mounjaro is a weight loss injection that works differently by stabilising blood sugar levels to reduce appetite and slowing stomach emptying, helping you feel fuller for longer.

Mounjaro and Zepbound are both medications containing the active ingredient tirzepatide, which mimics hormones to make the body feel fuller and reduce appetite.

Zepbound is the US name for the same weight loss medication, whereas in the UK tirzepatide is licensed under the name Mounjaro.

The medications function in the same way and are both prescribed for weight loss and metabolic regulation.

Mounjaro can result in a loss of body fat, which may affect menstrual cycles in some women. This is due to the fact that menstrual cycles are affected by levels of the hormone oestrogen, which is produced by fatty tissues in the body.

Individuals who experience changes in menstrual cycles from taking Mounjaro are recommended to consult a doctor for further advice.

It is not advisable to take Mounjaro (tirzepatide) during pregnancy, as there is limited data on its safety and impact on developing children.

If you are pregnant or intend to become pregnant and have taken Mounjaro, discuss your usage of this medication with your doctor immediately.

1. Jastreboff et al. (2022). Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine, 387(3), pp.205-216. Available at: https://doi.org/10.1056/NEJMoa2206038