Weight Loss Pen Price UK (October 2026)

01 · Price

What does a weight loss pen cost in the UK?

A Mounjaro pen costs between £169.99 and £299.99 per month at standard prices, depending on strength. Prices were last checked 25 October 2026.

Your first 2.5mg pen costs £129.99 with code FIRST40 (standard price £169.99). If you are switching to us from another provider at a higher dose, the new-customer discount still applies: a first order at 15mg is £259.99. After that, every future order is £25 off the standard price (code DOSE25). The Mounjaro discount code guide explains how both discounts work.

Weekly equivalents help when you compare pens. At standard prices, 2.5mg works out at £42.50 per week, 5mg at £47.50, 7.5mg at £61.25, 10mg at £68.75, 12.5mg at £72.50 and 15mg at £75.00.

02 · Included

What the price includes

The price shown is the price paid. The consultation is free, with no charge and no obligation, and a GPhC-registered prescriber reviews it rather than a scoring script. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.

Delivery is free, next-day and tracked, in discreet, temperature-controlled packaging. Orders placed by 3pm are dispatched the same day. Saturday delivery is £14.99. Needles, a sharps bin and injection guidance come with every order, and our prescribing team carries out ongoing monthly reviews. Payment is by Visa or Mastercard, Klarna or pay-monthly options, with no subscription lock-in.

Supply is official LillyDirect stock, sourced direct from Eli Lilly's UK distribution. All six strengths are in stock.

03 · Budget

Planning your first pens and first year

Treatment is a series of pens, not a single purchase, so plan by phase. These are standard prices before discounts. A new customer's first order is £40 less, and every later order is £25 less.

Many people settle at 5mg, 10mg or 15mg, and higher is not automatically better. Your prescriber guides the pace. For single-strength costs see the pages on 10mg pen pricing and 15mg pen pricing.

04 · Ordering

How ordering works

Ordering takes three steps. First, complete the free online consultation, a short health questionnaire. Second, a GPhC-registered prescriber reviews it, and unsuitable orders are refunded automatically. Third, our registered pharmacy dispenses and dispatches your pen, with free next-day tracked delivery.

You can start your free consultation now, or read our guide to buying weight loss pens online. Repeat orders re-check suitability, and nothing ships automatically.

05 · What the pen is

What is a weight loss pen?

A weight loss pen is a pre-filled injector that delivers a prescription medicine under the skin, and the one we supply is Mounjaro. Mounjaro is the brand name for tirzepatide, a once-weekly injectable made by Eli Lilly. In the UK it is licensed for weight management in adults and for type 2 diabetes.¹ It comes as a multi-dose KwikPen in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.

The phrase "weight loss pen" is used loosely online. It can mean Mounjaro, Wegovy, a daily liraglutide injection, or even an unregulated product sold with dramatic weight-loss claims. That matters for price, because the products are not interchangeable and cheap-looking offers may not be genuine.

Each Mounjaro KwikPen contains four weekly doses. Liraglutide, by contrast, is a daily injection supplied at 6mg per millilitre, so its cost structure and pen life differ. Wegovy is also once-weekly, with pens of 0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg. Its first pen is £99.99 on a first order. For current Wegovy prices see the all weight loss treatments page.

Mounjaro 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 increased physical activity. Individual results vary. This page is information, not a substitute for medical advice.

If you see a pen advertised with no consultation, treat it as a warning sign rather than a bargain. Genuine treatment always involves a prescription and a clinical consultation, which is built into the price you pay with a registered pharmacy.

One practical note on the word "pen": the KwikPen is not a disposable one-dose device. You dial the dose in the window each week, inject, recap, and keep the same pen for four doses. When it is empty, you dispose of it and start the next one.

06 · How it works

How does the pen work to reduce weight?

Tirzepatide activates two natural gut-hormone receptors at once: GIP and GLP-1. Together these help regulate appetite, slow how quickly the stomach empties, and improve the way the body responds to insulin.¹ In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.

This dual action distinguishes Mounjaro from single-action GLP-1 medicines such as semaglutide (Wegovy and Ozempic). A prescriber chooses based on your BMI, medical history and current medicines.

Tirzepatide has a half-life of about five days. After a final dose it takes roughly 4 to 5 weeks to clear the system. There is no way to speed this up, and nothing needs doing while it clears.

Because the mechanism supports a reduced-calorie diet rather than replacing it, the pen is only one part of the treatment. The licence says it must be used alongside a reduced-calorie diet and increased physical activity. When you compare price, remember that the pen is the medical part of a plan, and the plan needs your food and activity habits too.

Mounjaro is injected once a week, on the same day each week, at any time of day, with or without food. There is no "best" time of day: it works the same in the morning or evening. Many people choose a weekend morning so early side effects fall on days off, but the only thing that matters is consistency.

07 · Who can have it

Who can have a weight loss pen, and what about the NHS?

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. Examples include high blood pressure, high cholesterol, obstructive sleep apnoea, cardiovascular disease, prediabetes or type 2 diabetes.¹ It must be used alongside a reduced-calorie diet and increased physical activity.

A prescriber assesses your BMI, medical history and current medicines before deciding whether it is suitable. That is the reason the consultation exists, and the reason an order can be declined. If it is declined, you are refunded automatically in full. Pre-existing conditions and other medicines are the usual reasons for a different recommendation.

On the NHS, the picture is different. Mounjaro is available on the NHS, but access is being phased in over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition. The NHS primary-care rollout began in June 2025 with the highest-need groups first, initially BMI 40 and above with four or more qualifying conditions.⁴⁶ Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.

For cost planning, the NHS route means no pen price, though you may pay the standard prescription charge of £9.90 in England where it applies. Private treatment means paying for each pen, but you can start once a prescriber approves you. Neither route is right for everyone, and your GP can tell you where you sit in the local rollout. Asking your GP is free and does not stop you using private care later.

If you are unsure whether you qualify, the free consultation is the quickest way to find out, since it has no charge and no obligation. Start from the free consultation page.

08 · Dose ladder

How the dose ladder shapes what you pay

Everyone starts Mounjaro on 2.5mg once a week. This starting dose is about letting your body adjust, not about weight loss itself. After at least 4 weeks the dose increases to 5mg. It can then step up by 2.5mg at a minimum of 4-week intervals (7.5mg, 10mg, 12.5mg) up to a maximum of 15mg weekly, depending on how you respond and tolerate it.¹

That ladder explains the price pattern. In the first four pens you may buy four different pens, 2.5mg, 5mg, 7.5mg and 10mg, costing £879.96 at standard prices before discounts. After that, you stay on a maintenance pen. Many people settle at 5mg, 10mg or 15mg, but higher is not automatically better, and your prescriber guides the right pace.

Injection is under the skin once a week. Licensed 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. Rotate the site with each dose. Each KwikPen contains four weekly doses.¹³

If you miss a dose, take it as soon as you can within 4 days (96 hours) of the scheduled time, then carry on with your usual day. If more than 4 days have passed, skip the missed dose and take the next one on your normal day. Never take two doses within 3 days of each other. You can change your injection day if at least 3 days (72 hours) have passed since your last dose.

For budgeting, the ladder cannot be rushed to save money. A minimum of four weeks on each step is part of the licence. Your prescriber reviews tolerance and response.

Strength also changes the cost of mistakes. If a pen is damaged, frozen or wrong on delivery, contact us within 3 days, because dispensed medicines cannot otherwise be returned.

09 · Do they work

Do weight loss pens work, and how fast?

Mounjaro produced substantial average weight loss in trials, but results are gradual and individual. In the SURMOUNT-1 trial of 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone.²

These are trial averages. Individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them. At 72 weeks, 85% of participants on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5% of their body weight. Half of participants on 10mg and 57% on 15mg lost at least 20%.²

As a worked example, for someone starting at 100 kg, 20.9% is about 21 kg. That is straight arithmetic on the trial average, not a prediction for you, and trial averages do not predict your own result.

Pace matters for how you judge value. Weight loss on Mounjaro is gradual by design. The first weeks on 2.5mg are an adjustment phase and losses are usually modest. Most measurable progress builds from 5mg onward, month by month. Trials measured results at 72 weeks, so think in months, not days, and judge progress by trend, not individual weigh-ins.¹

Experiences in the first weeks differ widely. Some people notice appetite change and early loss in week one; others feel little until a higher dose. Both are normal. Early loss includes water weight, so the trend over weeks matters more than any single weigh-in. Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle. If new or worrying symptoms appear, speak to your prescriber and report them via the Yellow Card scheme.¹⁹

Your prescriber also reviews response. If you have lost less than 5% of your starting weight after 6 months on the highest dose you can tolerate, they will discuss whether continuing or stopping is right for you.¹ That review is part of why monthly clinical reviews are included with our service: the money you spend should be matched by a clinical check that the treatment is doing its job.

10 · Safety and fakes

Avoiding counterfeit and unsafe pens

The biggest price-related risk is buying a fake pen because it looks cheap. The MHRA has seized thousands of fake weight-loss pens in the UK and has issued alerts after falsified Mounjaro pens were identified. Fake pens have caused hospitalisations, and some contained insulin rather than tirzepatide.⁷

Only buy from a pharmacy you can verify on the GPhC register, never from social media, beauty salons or unverified websites. Genuine treatment always involves a prescription and a clinical consultation. A seller offering to supply without a consultation or prescription is a red flag, whatever the price. You can check any pharmacy on the GPhC register.¹²

Genuine UK stock is supplied through Lilly's official distribution to licensed pharmacies, and every pen carries a batch number and expiry date that can be checked. Our supply is official LillyDirect stock, direct from Eli Lilly's UK distribution.

When your pen arrives, look at it. A genuine UK Mounjaro pen comes from a registered pharmacy with a batch number and expiry date, arrives cold-chain packaged, and the solution inside is clear and colourless. Do not use a pen that has been frozen, looks cloudy or discoloured, has particles in it, is past its expiry, or has been above 30°C or out of the fridge for more than 30 days in use. If supply or packaging ever seems wrong, check the pharmacy on the GPhC register and contact the pharmacy before injecting.

Side effects are the second safety question. Mild nausea, altered appetite and tiredness are the commonest early effects and usually settle. Common side effects include nausea, diarrhoea, vomiting, constipation and abdominal discomfort, and anything new or lasting should go to your prescriber. You can also report suspected side effects through the Yellow Card scheme.¹⁹

Supplements sold as natural alternatives are not a like-for-like option. They are low-cost supplements with no clinical oversight, and dosing is not standardised. Their cheapness is a reason for caution, not a saving that compares with a prescribed, licensed pen. Our support team (Monday to Friday, 9am to 5pm, phone 0333 207 0413) can help if you are unsure whether something you have been offered is genuine.

11 · Saving money safely

Ways to lower the cost

The safe ways to lower what you pay are discounts and comparing live prices.

What does help legitimately: new customers save £40 on their first order with code FIRST40, and an automatic £25 reorder discount applies to every future order (code DOSE25). Klarna and pay-monthly options spread the cost, with no subscription lock-in.

Storage and travel protect the money you have already spent. 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, after which it should be discarded. Keep the cap on to protect it from light. You can fly with Mounjaro: carry pens in hand luggage, ideally in a cool bag with the prescription label or a copy of your prescription. Unopened pens should stay in the fridge and keep until the expiry date on the box. If an unopened pen has been out of the fridge, check the patient information leaflet and the pharmacy before using it.¹³

12 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹ Mounjaro must not be used during pregnancy, and it should be stopped at least one month before trying to conceive. Mounjaro slows stomach emptying, which can reduce how well oral contraceptive pills are absorbed: switch to a non-oral method, or add a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.