What Are GLP-1 Medications: Everything You Need to Know

Quick answer: What are GLP-1 medications? They are prescription treatments that mimic a natural hormone in your body to help regulate blood sugar, reduce appetite, and support medically supervised weight loss.

What are GLP-1 medications?

GLP-1 medications belong to a group of treatments called GLP-1 receptor agonists. GLP-1 stands for glucagon-like peptide-1, a hormone your gut naturally releases after you eat. This hormone helps to:

• Trigger the release of insulin when your blood sugar rises
• Reduce the amount of glucose your liver produces
• Slow down how quickly food leaves your stomach
• Send signals to your brain that you feel full

In people living with type 2 diabetes or those struggling with their weight, these processes can be disrupted. You might feel hungry again soon after eating, experience intense sugar cravings or notice that lifestyle changes alone aren’t enough to shift your weight.

GLP-1 medications work by acting on the same receptors as your natural GLP-1 hormone, enhancing your body’s own appetite and blood sugar control system. They are usually given as once-weekly injections using a pre-filled pen device.

How do GLP-1 medications help with weight loss?

GLP-1 medications support weight loss in several ways. Rather than relying on willpower alone, they change how your body and brain respond to food, hunger and fullness. This makes it easier to stick to a reduced-calorie diet and achieve steady, sustainable weight loss.

Appetite control & slower digestion

One noticeable effect of GLP-1 medications is slowed digestion. When your stomach empties more slowly, food stays in your system for longer, and you feel fuller after smaller portions.

This can mean:

• You feel satisfied after meals
• You’re less likely to pick at snacks
• Smaller, balanced portions become enough

Many patients describe this as a “quietening” of constant food thoughts. Instead of planning the next snack or craving something sweet, you may find that food takes up less mental space. 

Blood sugar balance

Blood sugar control and weight management are closely linked. When your blood sugar swings up and down throughout the day, you’re more likely to feel tired, irritable and hungry. That’s when reaching for high-sugar, high-fat foods becomes most tempting.

GLP-1 medications help by:

• Stimulating insulin secretion when blood sugar levels are high
• Reducing the amount of glucose released by the liver
• Helping prevent large spikes and crashes in blood sugar

By keeping blood sugar levels more stable, your energy is steadier and you’re less prone to those intense craving moments that can derail efforts. For people with type 2 diabetes, this also helps to reduce the risk of complications in a wider treatment plan.

Reduced cravings

As well as acting on the gut and pancreas, GLP-1 medications also seem to influence the brain’s appetite and reward centres. For many people, this translates into:

• Fewer cravings for sugary drinks, sweets and chocolate
• Less desire for large, carb-heavy meals
• A reduced urge to snack out of boredom or habit

This is helpful if you’ve tried multiple diets in the past and found that your appetite always seems to “fight back”. When your physical hunger and cravings are dialled down, lifestyle changes become much more realistic to maintain.

Common GLP-1 medications for weight loss available in the UK

Several GLP-1 medications are available on prescription in the UK. 

Your clinician will explain which options are suitable for you and whether treatment is available through the NHS, privately, or via a regulated online weight-loss service.

What are the side effects of GLP-1 medications?

Like all prescription medicines, GLP-1 treatments can cause side effects.

Common side effects

The most common side effects are digestive, particularly when you first start treatment or when the dose is increased. 

• Nausea (feeling sick)
• Vomiting
• Diarrhoea
• Constipation
• Bloating or wind
• Stomach discomfort or indigestion
• Loss of appetite
  

To reduce the likelihood and severity of symptoms, your prescriber will usually start you on a lower dose and gradually increase this over time. Simple lifestyle measures can also help, such as:

• Eating smaller, more frequent meals rather than large portions
• Avoiding rich, greasy or very spicy foods
• Limiting alcohol intake
• Staying well hydrated by sipping water throughout the day
  

If side effects are troublesome, don’t suffer in silence. Speak to your clinician or pharmacist – they should be able to help. 

Rare but serious side effects

Serious side effects are uncommon, but it’s important to be aware of them. 

• Pancreatitis. Symptoms may include severe, persistent abdominal pain that can spread to the back, often with vomiting
  
• Gallbladder problems. Gallstones or gallbladder inflammation, which may cause pain in the abdomen, fever or jaundice
  
• Kidney problems. Particularly if you become dehydrated due to vomiting or diarrhoea
  
• Severe allergic reactions. Such as swelling of the face, lips, tongue or throat, difficulty breathing or a widespread rash
  

If you experience any worrying symptoms, especially severe abdominal pain, chest pain, breathing difficulties or signs of an allergic reaction, you should seek urgent medical help by calling 999 or attending A&E.

Who should take or avoid GLP-1 medications?

GLP-1 medications are not designed as a quick fix or cosmetic slimming product. They are intended for adults living with obesity or weight-related health issues and would benefit from structured weight loss.

You may be considered for a GLP-1 medication if:

• Your BMI is 30 or above (in the obese range)
  
• Your BMI is 27 or above, and you have at least one weight-related condition
  
• You’ve already tried lifestyle changes, such as diet and exercise, but struggled with meaningful weight loss
  
• You are willing to engage in a comprehensive weight management plan, including dietary advice, movement and behaviour support
  

However, GLP-1 medications are not suitable for everyone. You should not take GLP-1 medicines if:

• You are pregnant, planning a pregnancy or breastfeeding
  
• You have a personal or family history of certain conditions affecting the thyroid like medullary thyroid carcinoma or a rare endocrine syndrome called MEN 2
  
• You have severe digestive problems such as gastroparesis
  
• You’ve previously had a severe reaction to a GLP-1 medication or any of its ingredients
  

Your prescriber will take a detailed medical history, review your current medicines and may request recent blood tests before deciding whether this treatment is suitable for you. 

How to take GLP-1 medications safely

Taking GLP-1 medications correctly is key to getting the best results and reducing the risk of side effects. In the UK, you should always follow the instructions given by your own healthcare provider and read the patient information leaflet supplied.

Here are some general safety tips:

• Stick to the prescribed dose and schedule
  Do not increase your dose faster than advised, even if you feel well.
  
• Use the injection pen correctly
  Your clinician, nurse, or pharmacist should show you how to use your injection pen before you start.
  
• Rotate injection sites
  Try not to inject into the same spot every time, as this can cause irritation or lumps under the skin.
  
• Store your medication properly
  Unused pens are usually stored in the fridge, away from the freezer compartment. Once in use, some pens can be kept at room temperature for a limited time.
  
• Avoid doubling up on doses
  In general, if it’s been too long since your last dose, you may be advised to skip the missed dose and wait for your next scheduled day.
  
• Keep up with regular check-ins
  Regular reviews help ensure the medication remains safe and effective for you.
  
• Combine medication with lifestyle changes
  GLP-1 medications work best when paired with healthy lifestyle habits. 

If you’re ever unsure about anything or your circumstances change (for example, you become pregnant or start a new medicine), speak to your GP, pharmacist or prescribing clinician for advice.

Conclusion

GLP-1 medications have transformed the landscape of medical weight management in the UK. By working with your body’s own hormone systems, they help reduce appetite, improve blood sugar control and support steady, clinically meaningful weight loss.

For more information on GLP-1 medications and alternatives, visit The Virtual Slimming Clinic today. We offer prescriptions and countless free resources to guide your weight-loss journey. 

Frequently Asked Questions (FAQs)

Which GLP-1 medications are approved in the UK?

In the UK, several GLP-1–based treatments are licensed for either type 2 diabetes, weight management, or both: Wegovy® (semaglutide), Ozempic® (semaglutide), and Mounjaro® (tirzepatide). 

Are GLP-1 medications safe?

GLP-1 medications have been studied in large clinical trials and are considered safe when used as recommended and under healthcare professional supervision. Most side effects are mild to moderate, particularly gastrointestinal symptoms such as nausea or constipation, which usually settle as your body adapts.

If you have specific concerns, such as a past medical condition or family history, raise them during your consultation.

How long do GLP-1 medications take to work?

Everyone is different, but many people notice a reduction in appetite within the first few weeks of treatment. Visible changes on the scales may take a little longer.

It’s common to see the most significant changes between 3 and 6 months, provided the medication is taken consistently and combined with lifestyle changes.

Are GLP-1 medications suitable for non-diabetics?

Yes. Some GLP-1 medications, such as Wegovy, are licensed explicitly for weight management in adults who do not have diabetes but who meet certain BMI and health criteria, with others sometimes prescribed “off-label”. 

That said, GLP-1 medications are not meant for individuals who simply want to lose a small amount of weight for cosmetic reasons.

What happens if I miss a dose of a GLP-1 medication?

• If it has been only a short time since your scheduled dose (for example, within a couple of days), take the missed dose as soon as you remember, then continue as usual.
  
• If more time has passed, you may be told to skip the missed dose and wait until your next scheduled injection.
  

Always follow the guidance in your patient information leaflet and, if in doubt, contact your clinician for personalised advice. Do not double up doses to “catch up”, as this can increase the risk of side effects.