Weight Loss Medication FAQs
Your guide to GLP-1 weight loss treatments
Prescription weight loss medication has transformed the treatment of obesity in recent years. Medicines such as Mounjaro (tirzepatide) and Wegovy (semaglutide) can help people lose a significant amount of weight by reducing appetite, making it easier to eat less and maintain healthier eating habits.
GLP-1 treatments are intended to be used alongside healthy lifestyle changes, including a balanced diet and regular physical activity. They are not a quick fix, but they can provide valuable support for people who have struggled to lose weight through lifestyle measures alone.
Interest in these medicines continues to grow, and new treatment options are becoming available. Wegovy is now available as both a once-weekly injection and a once-daily tablet, giving patients more choice about how they receive treatment.
Below we've answered some of the most commonly asked questions about GLP-1 weight loss medication.
What are GLP-1 weight loss medications?
GLP-1 weight loss medicines are prescription treatments that help reduce appetite and support weight loss in adults who meet specific clinical criteria.
GLP-1 (Glucagon-like peptide-1) is a natural hormone in the gut released after eating and attaches to receptors to tell the body that it has been fed and feels full. The GLP-1 medications work by mimicking these naturally occurring hormones and help regulate appetite by making you feel fuller for longer and reducing hunger.
Current GLP-1 treatments available in the UK include:
- Mounjaro® (tirzepatide) - a once-weekly injection
- Wegovy® (semaglutide) - available as a once-weekly injection or a once-daily tablet
Although Mounjaro also acts on another hormone called GIP (glucose-dependent insulinotropic polypeptide), both medicines work in a similar way to help reduce appetite and support weight loss.
These medicines are only available following assessment by a qualified healthcare professional to ensure they are safe and appropriate for you.
How do weight loss injections work?
GLP-1 medicines work by helping your body regulate appetite more effectively.
They:
- reduce feelings of hunger
- help you feel fuller after eating
- slow the rate food leaves your stomach
- make it easier to eat smaller portions.
Unlike some older weight loss medicines, GLP-1 treatments do not increase your metabolism or directly burn fat. Instead, they help you naturally eat fewer calories, making it easier to lose weight over time.
Which GLP-1 weight loss medication injection is best?
There isn't one medicine that is best for everyone.
The most suitable treatment depends on several factors, including:
- your BMI
- your medical history
- any health conditions you have
- medicines you already take
- whether you would prefer an injection or a tablet
- whether you prefer once weekly or daily treatment
- side effects you may experience
The main GLP-1 medicines currently available are Mounjaro and Wegovy.
Clinical studies suggest Mounjaro produces greater average weight loss than Wegovy (semaglutide) for many people, but both medicines can help achieve significant weight loss when combined with healthy lifestyle changes.
What's the difference between Mounjaro and Wegovy?
Both medicines reduce appetite but work slightly differently.
Mounjaro (tirzepatide)
- Once-weekly injection
- Acts on both GLP-1 and GIP receptors
- May produce greater average weight loss in clinical studies
Wegovy (semaglutide)
- Available as a once-weekly injection or a once-daily tablet
- Acts on the GLP-1 receptor
- Well-established treatment with extensive clinical experience
Both medicines are started at a low dose and increased gradually to reduce the chance of side effects.
Are tablets as effective as injections?
Wegovy tablets contain the same active ingredient (semaglutide) as Wegovy injections but are taken differently.
Some people prefer taking a tablet each day, while others find a weekly injection more convenient. Side effects may be reduced when using the weekly injection compared to the daily tablets.
Both options are designed to reduce appetite and support weight loss.
How do I take Wegovy tablets?
Wegovy tablets are taken once a day.
To help your body absorb the medicine properly, they should be:
- taken first thing in the morning on an empty stomach
- swallowed whole with a small amount of water
- followed by waiting at least 30 minutes before eating, drinking anything other than water or taking other medicines.
Following these instructions is important to ensure the medication works as intended.
How much weight can you lose with GLP-1 medications?
Weight loss varies from person to person.
Your results will depend on factors including:
- your starting weight
- your diet
- your physical activity
- how consistently you take the medication
- other medical conditions.
Clinical studies have shown that many people lose a meaningful amount of weight when GLP-1 medicines are combined with healthy lifestyle changes.
Steady, gradual weight loss is generally healthier and easier to maintain than rapid weight loss.
How long does it take for weight loss injections to work?
Many people notice their appetite decreases within the first few weeks of treatment.
Visible weight loss usually develops gradually over several months as the dose is increased according to the recommended schedule.
The dose is increased slowly to allow your body to adjust and reduce the chance of side effects.
Do GLP-1 weight loss treatments stop working over time?
For many people, weight loss continues while they remain on treatment and maintain healthy lifestyle changes.
Weight loss often slows after the initial stages, which is a normal part of the body's adaptation as weight decreases. This does not necessarily mean the medicine has stopped working.
Regular reviews with a healthcare professional can help determine whether treatment remains appropriate and whether lifestyle adjustments may improve ongoing progress.
What happens if you stop using GLP-1 weight loss treatment?
If you stop taking GLP-1 medication, your appetite is likely to increase again as the medicine leaves your body.
Without continuing healthy lifestyle habits, some people regain some or all of the weight they have lost.
For this reason, it's important to develop sustainable eating habits and regular physical activity while taking treatment.
If you are considering stopping treatment, it is advisable to discuss this with your prescribing clinician first.
What are the most common side effects?
Like all medicines, GLP-1 weight loss injections can cause side effects.
The most commonly reported side effects include:
- Feeling sick (nausea)
- Vomiting
- Diarrhoea
- Constipation
- Stomach discomfort
- Reduced appetite
- Indigestion
These symptoms are generally most noticeable when treatment begins or after a dose increase and often improve as the body adjusts.
Eating smaller meals and increasing the dose gradually as recommended by your prescribing clinician can help reduce gastrointestinal side effects.
Are GLP-1 medications safe?
The GLP-1 medicines licensed for weight loss in the UK have undergone extensive clinical testing and are regulated by the Medicines and Healthcare products Regulatory Agency (MHRA).
Like all prescription medicines, they are not suitable for everyone.
Before prescribing treatment, a healthcare professional will review your medical history, current medications and any health conditions to ensure the medicine is appropriate for you.
Regular monitoring throughout treatment helps ensure the medicine continues to be appropriate for your individual circumstances.
Can you drink alcohol while taking GLP-1 medication?
There is no specific reason why you cannot drink alcohol while taking GLP-1 medicines.
However, alcohol may make side effects such as nausea or stomach upset worse for some people and also adds extra calories, which may reduce your weight loss.
If you choose to drink alcohol while receiving treatment, moderation is generally recommended.
What foods should you avoid while using GLP-1 medicines?
There are no foods that everyone must avoid.
However, some people find that fatty, fried, rich or very large meals make side effects more noticeable, particularly when starting treatment.
Eating smaller portions, chewing food slowly and choosing balanced meals often helps improve comfort during treatment.
Can you exercise while taking GLP-1 weight loss medication?
Yes. Regular exercise is encouraged alongside GLP-1 weight loss medication unless a healthcare professional advises otherwise.
Exercise can help:
- improve weight loss
- preserve muscle mass
- improve heart health
- support long-term weight maintenance.
Combining aerobic exercise with strength or resistance training provides the greatest overall health benefits.
Can GLP-1 weight loss medication help reduce belly fat?
GLP-1 medications promote overall weight loss rather than targeting fat from one specific area of the body.
As body weight decreases, many people notice reductions in abdominal fat alongside reductions in fat stored elsewhere. However, it is not possible to selectively lose fat from one part of the body through medication alone.
Healthy eating and regular physical activity remain important components of reducing excess body fat.
Will I lose muscle as well as fat?
Whenever people lose weight, some muscle loss can occur alongside fat loss.
Eating enough protein and including regular strength or resistance exercise can help preserve muscle while losing weight.
Healthcare professionals generally recommend combining weight loss medication with healthy lifestyle habits to support body composition as well as overall health.
Are GLP-1 medicines better than Orlistat?
GLP-1 medicines and Orlistat work in different ways.
GLP-1 medicines reduce appetite by acting on hormones involved in hunger regulation and have been shown in trials to have a more pronounced effect on weight loss.
Orlistat works in the digestive system by reducing the amount of fat absorbed from food.
The best treatment depends on your individual circumstances, medical history and preferences.
Can you buy weight loss medication online in the UK?
Yes. Prescription weight loss medicines can be obtained through regulated UK online doctor and pharmacy services following a medical assessment.
You should only obtain prescription medicines from providers that are appropriately regulated and require a consultation before treatment is supplied.
Avoid buying prescription medicines from unregulated websites or social media, as these products may not meet UK safety standards.
Can you get weight loss medication on the NHS?
Some weight loss medicines are available on the NHS for people who meet specific eligibility criteria.
Eligibility depends on factors such as BMI, weight-related medical conditions and local NHS commissioning policies.
Many people who do not qualify for NHS treatment choose to access weight loss medication privately following an assessment by a qualified healthcare professional.
How much do weight loss injections cost?
The cost of treatment varies depending on the medicine prescribed, the dose required and the provider supplying the medication.
Because doses are gradually increased during treatment, monthly costs may change as treatment progresses.
When comparing providers, it is important to consider the overall service provided, including medical assessment, ongoing clinical support and regulated prescribing, rather than focusing on price alone.
Are GLP-1 medicines worth it?
For many people living with obesity or excess weight, GLP-1 medicines can be a valuable addition to a long-term weight management plan.
Clinical studies have shown these medicines can help people lose a meaningful amount of weight when combined with healthy eating and regular physical activity. Many people also report improvements in quality of life and increased motivation to maintain healthier habits.
However, they are not suitable for everyone, and long-term success still depends on developing healthy lifestyle habits alongside treatment.
Be the First to Know When Weight Loss Treatments Become Available
Dr Fox will soon be offering a range of prescription weight loss treatments, including both GLP-1 weight loss injections and oral weight loss medication, subject to clinical suitability and a medical assessment.
If you're interested in finding out more, you can register your interest today. Simply complete the notification form below, and we'll let you know as soon as these treatments become available through our online doctor service.
By joining our notification list, you'll receive an update when the service launches, along with further information about the available treatment options, eligibility criteria and how the online consultation process works.
There is no obligation to proceed with treatment, and registering your interest does not guarantee that a prescription will be issued. All prescriptions are subject to an assessment by a UK-registered clinician to ensure the treatment is appropriate and safe for you.
Authored 06 July 2026 by Dr C. Pugh
MB ChB University of Liverpool 2000. NHS GP and GP appraiser.
GMC no.
4712688
Reviewed by
Dr
J
.
Tweedie
,
Dr
B
.
Babor
Last reviewed 08 August 2026
Last updated 28 August 2026
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