Mounjaro 2.5mg Price UK: Starter Pen Cost and Your First Month (November 2026)

01 · What it costs

How much does Mounjaro 2.5mg cost?

A Mounjaro 2.5mg KwikPen costs £169.99 at our standard price. Each pen holds four weekly doses, so that is one pen every four weeks and £42.50 per week. This is the live price, checked on 10 November 2026, and the same one you see when you choose the 2.5mg pen and start a consultation.

• First order: £40 off with code FIRST40. The 2.5mg pen is the first order for most people, so this is where the discount is usually used.
• Repeat orders: £25 off every later order with code DOSE25.
• Subscribe & Save: £40 off every order on injections.

The checkout shows the final price before you pay. The price includes the free consultation and prescriber review, free next-day tracked delivery in temperature-controlled packaging, and needles and a sharps bin.

02 · How to order

How to order Mounjaro 2.5mg

For almost everyone, the 2.5mg pen is the first Mounjaro order. You complete the free consultation, a GPhC-registered prescriber reviews it and decides whether 2.5mg is right for you, and our pharmacy sends the pen. Orders approved by 3pm go out the same day. If the treatment is not suitable, your order is refunded automatically in full.

Mounjaro (tirzepatide) is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. It is used alongside a reduced-calorie diet and more physical activity. Individual results vary. This page is information, not a substitute for medical advice.

03 · Why everyone starts on 2.5mg

Why everyone starts Mounjaro on 2.5mg

Everyone starts Mounjaro on 2.5mg once a week. This starting dose is about letting your body adjust, not about weight loss itself.¹ Starting low makes digestive side effects less likely and less intense while your stomach gets used to emptying more slowly.

After at least 4 weeks the dose rises to 5mg, and it can then step up by 2.5mg at intervals of at least 4 weeks.¹ So the 2.5mg pen is a one-month pen for most people. Some people stay on it a little longer if they are sensitive to side effects, but it is not intended as a long-term dose for weight loss.

You may still notice changes on 2.5mg. Many people feel full sooner, think about food less and lose some weight in the first month. Others notice very little until 5mg. Both are normal.

04 · Your first month

What to expect in your first month on 2.5mg

Week 1

You inject once, on a day of the week you can stick to. Mounjaro is injected under the skin once a week, at any time of day, with or without food.¹ Some people notice less appetite within a day or two; some notice nothing yet.

Weeks 2 to 4

Appetite changes usually become clearer. The most common side effects are nausea, diarrhoea, vomiting, constipation and abdominal discomfort, and they are usually mild at this dose.¹ Eating smaller meals, stopping when you feel full and avoiding very fatty or fried food helps.

End of the month

Your prescriber reviews how you are getting on and whether to move to 5mg. Order your next pen a few days before your fourth injection so there is no gap. If you use the contraceptive pill, add a barrier method or switch to a non-oral method for four weeks after starting, and again after each dose increase.²¹

05 · Starter pen offers

Mounjaro 2.5mg offers and what happens after the first pen

Introductory offers are most common on the 2.5mg pen, because it is the first thing every new patient buys. With us, new customers get £40 off the first order with code FIRST40.

The more important number is what the next pens cost. Most people move to 5mg after a month, and the 5mg pen costs £189.99 at our standard price. After your first order, every repeat order is £25 off with code DOSE25, or you can choose Subscribe & Save for £40 off every order on injections.

If you step up every four weeks, your first four pens (2.5mg to 10mg) cost £879.96 at standard prices. Our Mounjaro prices page lists every dose.

06 · Comparing 2.5mg prices

Comparing Mounjaro 2.5mg prices between pharmacies

The 2.5mg pen is where headline prices are lowest and most varied. Across the UK pharmacies we track, it ranges from £143.96 to £179.99. Across the UK pharmacies we track, the gap between providers for the same dose runs from £27 to £40.03, and pens across all doses range from £143.96 to £339.00, checked on 10 November 2026. Boots lists Mounjaro from £179.00 to £339.00 depending on dose.

Compare the same dose on the same date, check whether a price is a first-order deal or the standard price, and add any consultation, delivery or needle charges. Our Mounjaro price comparison explains how to compare fairly, and Mounjaro prices by dose lists every strength with us.

07 · Who can start Mounjaro

Who can start on Mounjaro 2.5mg

Mounjaro is licensed for weight management in adults with a BMI of 30 or above, or a BMI between 27 and 30 with at least one weight-related condition such as high blood pressure, high cholesterol, obstructive sleep apnoea, cardiovascular disease, prediabetes or type 2 diabetes.¹ It is used alongside a reduced-calorie diet and more physical activity.

It is not suitable for everyone. Your prescriber will take extra care, or may recommend against treatment, if you have a history of pancreatitis, severe gut or digestive disease, diabetic retinopathy, or gallbladder problems.¹ It should not be used in pregnancy or while breastfeeding. Our page on weight loss injection eligibility explains the criteria in more detail.

08 · Your first injection

Getting ready for your first injection

Your pen arrives with needles, a sharps bin and instructions. Put it in the fridge as soon as it arrives: keep pens at 2 to 8°C and never freeze them.³ Licensed injection sites are the stomach area (at least 5cm from the belly button), the front of the thigh, or the back of the upper arm if someone else gives the injection.³ Each KwikPen holds four weekly doses.¹

Choose an injection day you can keep each week. If you ever need to change it, you can, as long as at least 3 days (72 hours) have passed since your last dose.¹ Our guides to injection sites and the dose schedule walk you through each step.

09 · After 2.5mg

Moving on to 5mg

After at least four weeks, most people move to 5mg, which is the first dose meant to drive weight loss. In SURMOUNT-1, adults on 5mg lost on average 15% of body weight over 72 weeks, compared with 3.1% with lifestyle changes alone.⁴ The 5mg price page covers what to expect at the next step.

10 · Safety, storage and missed doses

Safety, storage and missed doses on 2.5mg

Side effects on the starting dose are usually mild. The most common side effects, affecting more than 1 in 10 people, are nausea, diarrhoea, vomiting, constipation and abdominal discomfort.¹ Seek immediate medical help for severe, persistent stomach pain that may spread to your back, pain in the upper right abdomen with fever or yellowing of the skin or eyes, or signs of a severe allergic reaction.³

Keep pens in a fridge at 2 to 8°C and never freeze them; once in use, a pen can be kept out of the fridge not above 30°C for up to 30 days.³ If you miss a dose, take it within 4 days (96 hours) of the scheduled time; if more than 4 days have passed, skip it and take the next one on your normal day.¹ Our guides to side effects and injection sites go into more detail.

11 · Buying safely

Buying Mounjaro 2.5mg safely

Only buy from a pharmacy you can find on the GPhC public register.⁵ The MHRA has seized thousands of fake weight-loss pens in the UK, and some contained insulin rather than tirzepatide.² Every pen we supply comes through Eli Lilly's official UK supply and is dispensed by our registered pharmacy after a prescriber has reviewed your consultation.