How much weight can you lose on Mounjaro?

In the landmark SURMOUNT-1 clinical trial, participants taking the maximum 15mg maintenance dose of tirzepatide lost an average of 20.9% of their baseline body weight (approximately 52 lbs or 23.6 kg) over 72 weeks alongside diet and physical activity.

What is the starting dose for Mounjaro?

All patients begin at the 2.5mg starting dose once weekly for the first 4 weeks. This initiation dose allows the body to acclimate to the medication and minimizes gastrointestinal side effects before stepping up to 5mg.

How is Mounjaro supplied in the UK?

In the UK, Mounjaro is dispensed in a multi-dose KwikPen containing 4 weekly doses (a 28-day supply), plus replacement needles for each administration.

Dual GIP & GLP-1 Agonist Once-Weekly KwikPen MHRA & NICE Approved

Mounjaro (Tirzepatide): The Breakthrough Dual Hormone Weight Loss Injection

Mounjaro is the first and only licensed weight loss medication in the UK to target both GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 receptors. In clinical trials, patients achieved an unprecedented average body weight loss of up to 20.9%.

20.9%

Avg Weight Loss

Once

Weekly Dosing

2.5 - 15mg

Titration Range

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Key Prescription Facts

Active Ingredient:: Tirzepatide
Manufacturer:: Eli Lilly
Device:: KwikPen (4 Doses)
Administration:: Subcutaneous (Weekly)
Eligibility:: BMI ≥ 30 (or ≥ 27 w/ risk)
Dispensed by:: Click Pharmacy (UK)

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AI Key Takeaways • Quick Clinical Summary

What is Mounjaro (Tirzepatide) & Who Qualifies in the UK?

Mounjaro (Tirzepatide) is a prescription-only once-weekly subcutaneous injection licensed by the UK MHRA and approved by NICE for chronic weight management. It is a dual GIP and GLP-1 receptor agonist manufactured by Eli Lilly in a 4-dose pre-filled KwikPen.

Clinical Weight Loss: Patients achieved an average of 20.9% body weight reduction (up to 52 lbs) over 72 weeks in the SURMOUNT-1 trial.

Eligibility Criteria: Adults with a BMI ≥ 30 kg/m² (obese), or BMI ≥ 27 kg/m² with at least one weight-related condition (hypertension, dyslipidemia, sleep apnea).

Dosing Schedule: Starts at 2.5mg/week for 4 weeks (escalation phase), increasing every 4 weeks to maintenance doses of 5mg, 7.5mg, 10mg, 12.5mg, or 15mg.

UK Availability: Prescribed online via registered UK GPhC pharmacies like Click Pharmacy, with next-day cold-chain Royal Mail delivery.

How Does Mounjaro (Tirzepatide) Work?

While previous weight loss injections (such as Wegovy and Saxenda) exclusively stimulate the GLP-1 receptor, Mounjaro is a first-in-class dual GIP and GLP-1 receptor agonist. These two incretin hormones are naturally released by the gut following food intake:

1. GIP Receptor Action

Glucose-dependent insulinotropic polypeptide (GIP) improves fat cell metabolism, regulates energy expenditure, and enhances insulin sensitivity while reducing nausea associated with standalone GLP-1 stimulation.

2. GLP-1 Receptor Action

Glucagon-like peptide-1 (GLP-1) acts on hunger-regulating centers in the hypothalamus, curbing appetite, quieting persistent "food noise," and delaying stomach emptying so meals keep you satisfied longer.

SURMOUNT-1 Clinical Trial: What Weight Loss Can You Expect?

The landmark phase 3 SURMOUNT-1 clinical trial evaluated 2,539 adults with obesity (or overweight with at least one comorbidity). Over a 72-week period with lifestyle interventions, the results demonstrated unprecedented efficacy:

Mounjaro Dose	Average % Body Weight Lost	Average Weight Lost (kg / lbs)
5mg (Low Dose)	15.0%	~16.0 kg (35.3 lbs)
10mg (Medium Dose)	19.5%	~21.0 kg (46.3 lbs)
15mg (Max Maintenance)	20.9%	~23.6 kg (52.0 lbs)

Reference: Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med 2022; 387:205-216.

Mounjaro KwikPen Titration & Dosing Schedule

To minimize gastrointestinal side effects and give your body adequate time to adapt, Mounjaro follows a strict 4-week titration escalation schedule:

2.5mg

Weeks 1 to 4: Initiation Dose

Start with 2.5mg injected once weekly. This dose allows your digestive system to acclimate and is not intended as a long-term maintenance dose.

5mg

Weeks 5 to 8: First Therapeutic Dose

Increase to 5.0mg once weekly. Many patients begin experiencing significant appetite suppression and steady weight loss at this stage.

7.5mg

Weeks 9 to 12: Intermediate Escalation

If well tolerated and further weight loss is clinically indicated, your prescriber will increase your dose to 7.5mg once weekly.

10-15mg

Weeks 13 and Beyond: Higher Maintenance Doses (10mg, 12.5mg, 15mg)

Doses continue to increase in 2.5mg increments every 4 weeks up to a maximum of 15mg weekly, as approved by your Click Pharmacy clinician.

Side Effects & Practical Management Tips

Like all incretin mimetics, Mounjaro can cause side effects, particularly during dose increases. The majority are mild and temporary:

Nausea & Acid Reflux

Eat smaller, more frequent meals. Avoid spicy, heavy, or high-fat foods. Sip ginger tea or water throughout the day.

Constipation

Ensure at least 2 to 2.5 liters of water daily. Increase dietary fiber intake through leafy greens and flaxseeds.

Diarrhea & Cramping

Stay hydrated with electrolyte solutions. Avoid carbonated beverages and artificial sweeteners.

Injection Site Reactions

Rotate your injection site each week between your lower abdomen, front of thighs, and upper outer arms.

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