What Is the Best Injection for Weight Loss at Home? UK Options Compared (October 2026)

01 · The short answer

Which weight loss injection works best at home?

Mounjaro and Wegovy are the two licensed once-weekly pens that act on gut hormones, and most UK adults compare them. Both are pre-filled pens you use yourself, once a week, with no clinic visit for each dose. Neither is a quick fix: both are licensed alongside a reduced-calorie diet and increased physical activity.¹

Mounjaro is tirzepatide. It activates two natural gut-hormone receptors at once, GIP and GLP-1, which helps regulate appetite, slows how quickly the stomach empties and improves how the body responds to insulin.¹ That dual action is what separates it from single-action GLP-1 medicines such as semaglutide (Wegovy). In SURMOUNT-1, 2,539 adults on tirzepatide lost on average 15% of body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone. These are trial averages and individual results vary.²

Your BMI, medical history and current medicines decide what a prescriber will approve, and tolerability matters as much as the headline average. You can start with a free, no-obligation online consultation reviewed by a GPhC-registered prescriber.

02 · Side by side

At-home injection options compared

Wegovy and Mounjaro both follow a step-up schedule so your body can adjust, and your prescriber sets the pace.

03 · Costs

What a home weight loss injection costs

Private treatment is paid for month by month, so plan by pen. One Mounjaro pen contains four weekly doses, and the standard price of the 2.5mg starter pen is £169.99. Your first 2.5mg pen costs £129.99 with code FIRST40 (standard price £169.99). If you are switching to us at a higher dose, say 15mg, your first order is £289.99. After that, every later order is £25 off the standard price (code DOSE25).

If you step up after 4 weeks on each of 2.5mg, 5mg, 7.5mg and 10mg, your first four pens cost £959.96 at standard prices before discounts. A first year (52 weeks, 13 pens) costs £2,711.88 if you settle at 5mg, up to £3,599.88 at 15mg, again before discounts. If you settle at 7.5mg, 10mg or 12.5mg, the monthly prices are £279.99, £290.99 and £319.99.

For context, across the UK pharmacies we track, Mounjaro standard pens range from £143.96 to £339.00 per month depending on dose and provider, checked 12 October 2026. Boots' Mounjaro dose prices run from £179.00 to £339.00. The consultation is free, the price shown is the price paid, and there are no subscriptions; Klarna and pay-monthly options are available. All six doses are in stock.

04 · Getting started

How ordering works

Ordering takes three steps. First, complete the free online consultation, a short health questionnaire with no obligation. Second, a GPhC-registered prescriber reviews it; payment is taken when you place the order, and if the prescriber decides the treatment is not suitable, the order is refunded automatically in full. Third, our registered pharmacy dispenses your pen, with same-day dispatch when ordered by 3pm and free next-day tracked delivery in temperature-controlled, discreet packaging. Needles, a sharps bin and injection guidance come with every order. Mounjaro is supplied through official LillyDirect supply, and our GPhC registration number is 9012878.

05 · How the injections work

How weight loss injections work

Weight loss injections work by mimicking natural gut hormones that signal fullness, so you feel satisfied sooner and less hungry between meals. They do not melt fat on their own. They make a reduced-calorie diet easier to follow, which is why the licence requires both a diet and more physical activity.¹

Tirzepatide, the active ingredient in Mounjaro, is the first treatment of its kind to activate two receptors at once: GIP (glucose-dependent insulinotropic polypeptide) and GLP-1. Together these help regulate appetite, slow how quickly the stomach empties and improve how the body responds to insulin, which is relevant to blood sugar.¹ Single-action GLP-1 medicines such as semaglutide (Wegovy and Ozempic) work on one of those two pathways.

Slower stomach emptying is why smaller, slower meals tend to feel better on treatment, and why large, very fatty or very sugary meals can sit heavily. Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle.¹ If stomach pain is severe or persistent, get medical help straight away. For any other symptom that worries you, speak to your prescriber, and report suspected side effects through the Yellow Card scheme.¹⁹

Tirzepatide has a half-life of about five days, so 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.¹

It also helps to understand what these medicines are not. They are prescription weight loss treatments for adults whose weight puts their health at risk, assessed individually by a prescriber who looks at your medical history, current medicines and weight-related conditions such as high blood pressure.

This is why a product marketed as a natural or budget alternative cannot be compared like for like. A low-cost supplement has no clinical oversight and no standardised dosing, whereas a licensed pen has a defined dose ladder, a patient information leaflet and a regulator behind it. If you want a fuller overview of the category, our weight loss injections guide explains the main types, and our weight loss treatments overview covers tablets and other routes.

Appetite effects are tied to treatment, which is why planning for the long term, including diet, protein and activity habits, matters from the first week rather than after you stop.

06 · Mounjaro, Wegovy and others

Mounjaro, Wegovy and other options

Mounjaro and Wegovy are both once-weekly injections for weight management, but they contain different medicines and follow different dose ladders. Choosing between them is a conversation with your prescriber, not a league table.

Mounjaro is tirzepatide, made by Eli Lilly, licensed in the UK for weight management in adults and for type 2 diabetes. It comes as a multi-dose KwikPen in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg, each pen holding four weekly doses.¹ You always start on 2.5mg, and after at least 4 weeks the dose rises to 5mg, then can step up by 2.5mg at minimum 4-week intervals to a maximum of 15mg weekly depending on response and tolerance.¹

Wegovy is semaglutide. Its pens are 0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg once weekly, stepping up after at least 4 weeks and reaching the 2.4mg maintenance dose from week 17.¹⁸ The 2.4mg dose is the licensed maintenance dose for weight management. The first large trial built to compare tirzepatide with semaglutide directly is SURMOUNT-5, and your prescriber can talk you through it.¹⁵ You can see our current Wegovy pricing on our treatments page; the first pen is priced from £99.99 as a first-order price.

Liraglutide, sold as Saxenda and in products such as Erly, is a daily injection supplied at 6mg per millilitre, unlike the once-weekly pens. Its results figures vary, so your prescriber can advise whether it fits.

Weight loss tablets are a separate category. Wegovy tablets and Foundayo are licensed oral options with their own product information.²⁰²¹

Which suits you? If you want the lowest injection burden, a weekly pen beats a daily one. If you tolerate one medicine badly, a prescriber may suggest the other.

For a deeper look at the product we supply, the Mounjaro pen page shows live prices, and our at-home Mounjaro guide covers what home treatment looks like week to week.

07 · Who can have injections

Who can have weight loss injections?

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. Body mass index is your weight in kilograms divided by your height in metres squared, and it is the starting point for eligibility, not the whole picture.¹

Qualifying weight-related conditions include high blood pressure, high cholesterol, obstructive sleep apnoea, cardiovascular disease, prediabetes and type 2 diabetes. Treatment must be used alongside a reduced-calorie diet and increased physical activity.¹ A prescriber assesses your BMI, medical history and current medicines before deciding whether it is suitable for you.

That assessment is why a consultation is not a formality. Our prescribers are GPhC-registered and review each questionnaire individually rather than running 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.

People often ask who cannot take Mounjaro. You should not take Mounjaro if you are allergic to tirzepatide or any of its ingredients, and it should not be used during pregnancy or while trying to conceive. 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. Always share your full medical history and medicine list during consultation.¹³ Two practical points are worth knowing in advance. First, Mounjaro slows stomach emptying, which can reduce how well oral contraceptive pills are absorbed.⁷ The SmPC advises switching to a non-oral method, or adding a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.¹ Mounjaro must not be used during pregnancy, and it should be stopped at least one month before trying to conceive. If you become pregnant during treatment, stop the medicine and tell your prescriber promptly. Second, if you use insulin or a sulfonylurea, doses may need adjusting because of the risk of low blood sugar, which is something to raise at your consultation.

If you are under the thresholds, treatment may not be appropriate, and a prescriber will say so. Being told no is a safe outcome, not a failure. Equally, being eligible does not mean you must start: some people choose to try structured diet and activity changes first.

There is also a real difference between a licensed pen assessed for you and the unlicensed products sold online. Be wary of any seller offering to supply without a consultation or prescription, and check that a pharmacy appears on the GPhC register.¹² The MHRA publishes counterfeit medicine alerts and runs the Yellow Card scheme for suspected side effects or fake products.⁷

Pages claiming you can make Mounjaro or a GLP-1 at home, such as our explainers on making Mounjaro at home and making GLP-1 at home, exist to explain why that is not possible or safe. The route that works is a prescription from a registered pharmacy.

Finally, price changes do not alter eligibility. Pharmacy sell prices vary because of confidential discounts, which is why we show ours live.

08 · NHS or private route

NHS or private: which route suits you?

Mounjaro is available on the NHS, but access is being phased in over several years, so many adults who meet the licensed criteria still look at private treatment. Both routes use the same medicine; the difference is who qualifies first and how quickly you can start.

NICE recommends Mounjaro 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 people with a BMI of 40 or above and four or more qualifying conditions. Full rollout is expected to take years.⁴⁶ You can read the official overview in the NHS guidance and ask your GP where your area stands.⁵

So, do you qualify for Mounjaro on the NHS? If your BMI and conditions fall inside the current stage of the phased rollout, your GP or a specialist weight management service can discuss it. If they do not yet, that does not mean you are ineligible long term, because the groups are expanding over time. NHS access to Wegovy runs through specialist weight-management services, so ask your GP.

The NHS prescription charge for medicines in England is £9.90 per item where a charge applies; ask your pharmacy or GP what applies in your situation.

What does private treatment offer? The licensed threshold is wider than the NHS rollout stage: a BMI of 30 or above, or between 27 and 30 with a weight-related condition.¹ You can start through an online consultation without waiting for a referral, with the medicine delivered to your door. You pay for the pen, and you get ongoing monthly reviews, dose-titration and follow-up assessments from the prescribing team, plus side-effect support.

Neither route is a better choice in every case. If you are in a group the NHS is currently treating, waiting for an appointment costs nothing. If you are not, or you cannot wait, regulated private treatment is a legitimate alternative. Both involve clinical assessment, and both are designed around diet and activity alongside the injection.

One caution: if you move between routes, tell each prescriber what you are taking. Repeat orders with us re-check suitability and there is no auto-shipping, so a change in your health or medicines gets picked up before the next pen is sent.

Surgery is another route some people consider. Weight loss surgery is a major decision usually handled through specialist weight management services, so it is worth asking your GP what thresholds apply in your area.

09 · Results and realistic pace

How much weight can you lose, and how fast?

The most reliable evidence for tirzepatide comes from SURMOUNT-1, where 2,539 adults lost on average 15% of 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, and individual results vary. Treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.

To make that concrete, for someone starting at 100 kg, 20.9% is about 21 kg. Your own starting body weight, dose, diet and response will differ, and trial averages do not predict your own result.

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 Those proportions show how common meaningful loss was in the trial, which is different from promising it for any individual.

Which injection makes you lose weight the fastest? 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.¹ Think in months, not days, and judge progress by trend rather than individual weigh-ins.

Early experience differs widely. Some people notice appetite change and early loss in week one, others feel little until a higher dose, and both are normal. Early loss includes water weight, so the trend over weeks matters more than any single weigh-in.¹

Your prescriber 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 a safeguard, not a penalty.

What happens if you stop? Appetite effects are tied to treatment, so planning matters. In SURMOUNT-4, people who stopped tirzepatide after 36 weeks regained on average 14% of body weight over the following year, while those who continued treatment lost a further 5.5% on average. Stopping should always be planned with your prescriber.¹⁴ Building habits early, particularly protein, resistance exercise and regular activity, protects what you have achieved.

You can track progress with GLPTrackr, our free companion app for logging a GLP-1 journey on iOS and Android. Logging doses, weight and symptoms makes your monthly review more useful and shows the trend that matters.

A final word on expectations. Be suspicious of any product or seller promising dramatic weight-loss claims in weeks.

10 · Injecting safely at home

Best practices for safe injections at home

Mounjaro is injected under the skin (subcutaneously) once a week, on the same day each week, at any time of day, with or without food.¹ Our step-by-step guide to injecting tirzepatide at home goes further, and your pen's leaflet and instructions remain the authority.¹³

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. Rotate the site with each dose. Each KwikPen contains four weekly doses.¹

Setting the dose is simple. You turn the dose knob until the indicator shows the correct dose in the window. For pressing and holding the injection, follow the pen's instructions.

There is no best time of day. Mounjaro works the same morning or evening. What matters is the same day each week, so pick a day you will remember. Many people choose a weekend morning so early side effects fall on days off.

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 entirely and take the next one on your normal day. Never take two doses within 3 days of each other.¹ You can also change your injection day if at least 3 days (72 hours) have passed since your last dose.

Do not alter doses yourself. Changing doses outside the licence means unknown dosing accuracy and no safety data.¹

Practical safety habits help too. Wash your hands, check the pen label matches your prescription, use a new needle each time, and dispose of needles in the sharps bin we include with every order. Never share a pen.

Contact your prescriber if side effects are severe or do not settle, and report suspected reactions through the Yellow Card scheme. For severe, persistent stomach pain, swelling of the face or throat, or difficulty breathing, get medical help straight away.¹⁹ Our team is available Monday to Friday, 9am to 5pm on 0333 207 0413 or support@everydaymeds.co.uk.

11 · Storage, travel and delivery

Storing, travelling with and receiving your pen

Keep Mounjaro 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 at a temperature not above 30°C for up to 30 days after first use, and must then be thrown away. Do not use a pen that has been above 30°C or has been frozen.¹ Keep the pen cap on to protect it from light, and never use a pen that has been frozen.

Unopened pens should stay in the fridge and keep until the expiry date printed on the box. If an unopened pen has been out of the fridge, check the patient information leaflet and ask the pharmacy before using it, rather than relying on a remembered day limit; figures circulating online often come from other countries' labels.¹³

You can fly with Mounjaro. Carry pens in hand luggage, because hold luggage can fall below freezing, ideally in a cool bag with the prescription label or a copy of your prescription. In-use pens tolerate up to 30 days not above 30°C, so most holidays need no special arrangements; for hot climates use an insulated pouch. Check destination rules for travelling with prescription injectables before you fly.¹

Delivery is designed around this cold-chain requirement. Orders arrive by free next-day tracked DPD delivery in temperature-controlled, discreet packaging. Saturday delivery is £14.99. Same-day dispatch applies when you order by 3pm. When your parcel arrives, unpack it promptly and put unopened pens in the fridge.

Why does supply source matter? Genuine KwikPens come from official LillyDirect supply, sourced directly from Eli Lilly's UK distribution, and are dispensed by a registered pharmacy. Counterfeit weight loss injections are a real risk online, so buy only from pharmacies on the GPhC register, and treat any seller offering to supply without a consultation or prescription as a warning sign.⁷¹²

The trade-off is that you are responsible for storage, so make fridge space part of your routine.

Refund rules are worth knowing. Declined consultations are refunded in full automatically. Dispensed prescription medicines cannot be returned except faulty, damaged or wrong items, which you should report within 3 days; refunds take 5 to 10 working days.

If you travel often, ask your prescriber about timing your injection day around trips. You can change your injection day as long as at least 3 days have passed since your last dose, which makes planning around holidays straightforward.

12 · Diet, muscle and lifestyle

Diet, protein and exercise on treatment

No food is banned on Mounjaro, including bananas, but some choices make treatment easier. Prioritise protein at each meal, vegetables and fibre, and regular fluids. Many people feel worse after very fatty, fried or very sugary food, and large portions sit heavily because the stomach empties more slowly, so smaller, slower meals work better. Treatment is licensed alongside a reduced-calorie diet, so the aim is a sustainable deficit rather than a perfect food list.

The practical advice is simpler: cut back on the fried and very sugary foods that tend to cause discomfort on treatment, and build meals around protein and vegetables.

Protecting muscle matters. Some of any rapid weight loss comes from lean tissue, and protecting muscle protects your metabolism, strength and appearance. The two levers are adequate protein, including a protein source at every meal, which is harder when appetite is low, and resistance exercise two or more times a week. This matters more, not less, as the dose rises and appetite falls.

Exercise is part of the licence, not an optional extra. Nothing special is required: the evidence-backed pattern is regular moderate activity such as brisk walking, plus resistance work for muscle. Start where you are and build. On injection days with early side effects, lighter movement still counts. Exercise also protects against regain if you later stop treatment.

Alcohol has no direct interaction with Mounjaro, but drinking on a reduced appetite and emptier stomach can hit harder than usual, and alcohol adds calories that work against your goals. If you also take insulin or a sulfonylurea, alcohol increases the risk of low blood sugar. Moderation is the sensible rule, and many people find their desire for alcohol drops on treatment.

Hydration and gentle routines help in the first days after each injection, when mild nausea or tiredness is most likely. Eating slowly, stopping at the first sign of fullness and avoiding lying down straight after meals are common-sense habits to try, and your prescriber can advise if symptoms persist.

Our explainer on high-street appetite suppressants sets out why those are different from a prescribed medicine. Other injection types sold in clinics, such as those covered in our pages on meso injections and H2 injections, are not the licensed GLP-1 pens discussed here.

The goal is a healthy weight you can sustain, with a pen as one tool and food, movement and sleep as the others. Monthly reviews with our prescribing team keep that plan on track.

13 · 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