Question 1

Which GLP-1 is best for weight loss?

Accepted Answer

Mounjaro typically delivers the highest average weight loss in clinical trials, because it works on two hormones (GLP-1 and GIP) while Wegovy works on GLP-1 only. People taking the maximum 15mg dose of Mounjaro lost around 22.5% of their body weight after 72 weeks, compared to 20.7% on the new 7.2mg dose of Wegovy. Both are weekly injections.

The "best" treatment for you depends on your medical history, your goals, and how well you tolerate the medication. Complete a Voy assessment and a UK-registered prescriber will recommend the right treatment for you.

Question 2

How do I get weight loss injections in the UK?

Accepted Answer

You can get weight loss injections in the UK through the NHS or a private provider like Voy.

Through the NHS, Wegovy is available through a specialist weight management service with a GP referral, usually from a BMI of 35 with weight-related health problems. Mounjaro is also available through specialist services, or directly from your GP if you have a BMI of 40 and at least four weight-related health problems. Waiting times can run from months to years.

Through Voy, you complete an online assessment from home. A UK-registered prescriber reviews it within 24 hours, and your medication is dispatched within 1 working day of approval. We can prescribe from a BMI of 25, if it's clinically appropriate for you.

You can't get weight loss injections without a clinical assessment. Anyone offering them without one isn't operating safely or legally.

Question 3

Is there a pill version of weight loss injections?

Accepted Answer

Yes, the Wegovy pill is the first oral GLP-1 medicine approved for weight loss. It contains the same active ingredient as the Wegovy injection (semaglutide) in tablet form, taken once a day. It launched in the US in January 2026 but isn't yet available in the UK, with MHRA approval expected by late 2026. In clinical trials, the Wegovy pill produced up to 16.6% weight loss over 64 weeks.

Orlistat is currently the only weight loss pill available in the UK. It works differently to the Wegovy pill, by blocking fat absorption rather than suppressing appetite.

Question 4

Can I get weight loss injections on the NHS?

Accepted Answer

Yes, the NHS does prescribe weight loss injections, but eligibility is strict and waiting lists are long.

If you have a BMI of 40 or more with multiple weight-related health problems, your GP may be able to prescribe Mounjaro. For Wegovy, you'd need a referral to a specialist weight management service. Lower thresholds apply for some ethnic backgrounds.

If you don't meet the criteria or can't wait years to start, a private prescription through Voy gives you faster access. We can prescribe from a BMI of 25 if it's clinically appropriate, with prescriber review within 24 hours.

Question 5

How much do weight loss injections cost in the UK?

Accepted Answer

Costs depend on whether you access them through the NHS or privately, and which medication and dose you're on.

On the NHS, you'll pay the standard prescription charge of £9.90 per item in England, or nothing in Scotland, Wales, and Northern Ireland. NHS access is limited to people who meet strict eligibility criteria.

Privately, costs vary depending on the provider and what's included in your treatment. Some providers offer medication only, while others include clinical support, dose adjustments, and side-effect management.

At Voy, Wegovy starts from £119 per month and Mounjaro from £189 per month, with longer plans offering better value. Costs typically rise as your dose increases over the first few months. New customers get £50 off their first order, and your treatment includes ongoing access to your clinical team in-app or by phone, dose adjustments when needed, and side-effect support throughout.

Question 6

How do I use weight loss injections?

Accepted Answer

Most weight loss injections are taken once a week from a pre-filled pen, including Mounjaro and Wegovy. Some, like Saxenda, are taken daily. You can inject into your stomach, thigh, or upper arm, rotating the site to reduce irritation.

For weekly injections, take your dose on the same day each week, at any time of day, with or without food. If you miss a dose, take it as soon as you remember. For Mounjaro, this needs to be within 4 days; for Wegovy, within 5 days. If you're past that window, skip the missed dose and continue with your next scheduled one.

Your first delivery includes everything you need to inject safely at home: needles, a sharps bin for safe disposal, and a patient information leaflet with full instructions.

For step-by-step guidance, see how to inject Mounjaro and how to inject Wegovy.

Question 7

How often do you take weight loss injections?

Accepted Answer

It depends on which medication you're on. Mounjaro and Wegovy are taken once a week, on the same day each week. Saxenda is taken once a day.

Question 8

How quickly do weight loss injections work?

Accepted Answer

Most people start to feel reduced appetite within the first 1 to 2 weeks of treatment. Visible weight loss usually begins around 4 weeks in, with averages of 2 to 4% of body weight by the end of month 1, depending on which medication you're on. By week 12 on Wegovy, most people have lost around 6% of their starting weight, while on Mounjaro week by week the average is around 8% by the same point.

Your dose is increased step by step over the first few months, so the early weeks are about helping your body adjust rather than maximum weight loss. Results vary depending on your starting weight, dose, and how well you combine treatment with diet and exercise.

Question 9

How long can I stay on weight loss injections?

Accepted Answer

Weight loss injections are designed for long-term use. Clinical trials show people continue to benefit through 72 weeks (around 16 months) and beyond.

Most people stay on treatment as long as they're benefiting from it, tolerating it well, and clinically appropriate to continue. On the NHS, Wegovy is capped at 2 years. Mounjaro doesn't have a fixed time limit but is reviewed regularly. Privately through Voy, there's no fixed time limit if it's still clinically appropriate.

When you reach your goal weight, your prescriber can adjust your treatment plan: some people stay on a lower maintenance dose to help prevent weight regain, while others gradually reduce their dose over time. We recommend a gradual reduction rather than stopping cold turkey, as suddenly stopping can lead to weight regain when the appetite-regulating effects wear off. Tapering down lets your body adjust slowly, gives you time to consolidate the lifestyle habits you've built, so you can maintain your weight loss for the long term.

Question 10

Where can I buy weight loss injections?

Accepted Answer

Weight loss injections are prescription-only medicines in the UK. You can't buy them over the counter, and any pharmacy or website offering them without a clinical assessment isn't operating safely or legally.

Through the NHS, Wegovy is available through a specialist weight management service. Mounjaro is also available through specialist services or via your GP if you meet the criteria.

Through a private provider like Voy, you complete an online assessment from home. A UK-registered prescriber reviews whether it's suitable for you and your medication is sent directly to your door.

Counterfeit weight loss injections are a growing problem in the UK. Always check that any provider is registered with the General Pharmaceutical Council (GPhC) and the Care Quality Commission (CQC) before buying.

Question 11

Do I need to tell my doctor I'm on a GLP-1?

Accepted Answer

Yes, it's strongly recommended. Letting your GP know you're taking a GLP-1 medication like Mounjaro or Wegovy means they can review your other prescriptions and monitor any conditions that might be affected.

This is especially important if you take:

Diabetes medications: GLP-1s reduce blood sugar, so medicines like metformin may need adjusting as your levels improve.
Blood pressure medications: as you lose weight, your blood pressure often improves, so your dose may need to be reviewed.
The contraceptive pill (if you're on Mounjaro): Mounjaro can reduce how well oral contraceptives are absorbed. You'll need to use a barrier method like condoms for 4 weeks after starting and for 4 weeks after each dose increase, or your GP may switch you to a non-oral method like the coil or implant.
Oral HRT: GLP-1s slow how quickly your stomach empties, which can affect how well oral hormones are absorbed. Your GP may switch you to a patch, gel, or spray.
Thyroid medications: levothyroxine absorption can be affected by GLP-1s, so your GP will need to monitor your thyroid function and may adjust your dose or timing.

Your prescriber will check your full medication list during your eligibility assessment. For the full picture, see what medicines you can and can't take with Mounjaro.

Question 12

Do I need to tell my surgeon I'm on a GLP-1 before surgery?

Accepted Answer

Yes. Tell your surgical team and anaesthetist as soon as surgery is planned, whether for a general anaesthetic or deep sedation (like an endoscopy or some dental work).

GLP-1 medications like Mounjaro and Wegovy slow how quickly your stomach empties, which can raise the risk of food coming back up during anaesthesia. The MHRA has issued specific guidance recommending that you continue your GLP-1 in the lead-up to surgery, with extra precautions taken by your anaesthetic team. This may include changes to your usual fasting instructions or the anaesthetic technique used. Don't stop or pause your treatment without advice from your surgical or clinical team.

Weight loss treatments at Voy

Everyone's different, and so is every Voy treatment.

Find the best weight loss treatment for you

BMI Calculator

Height

Weight

Your BMI

00.0

Weight loss success stories

How it works with Voy

What to expect in your first delivery

What are weight loss injections?

Can you get weight loss injections on the NHS?

How NHS and Voy compare

Weight loss medications: FAQ

Our medical leadership

Wegovy 7.2mg

Retatrutide for weight loss

What is Orforglipron?

Switching between Wegovy & Mounjaro