GLP-1 Drugs For Weight Loss: Wegovy, Saxenda, Ozempic and semaglutide explained

If you’ve been hearing about “Ozempic”, “the diabetes weight loss drug” or “GLP-1 for weight loss” on the news or social media, it can be hard to tell:

• Which medicines are actually licensed for weight loss

• How semaglutide weight loss injections differ from standard diabetes treatments

• Whether it’s safe or legal to get Ozempic without prescription online

This guide breaks down:

• What GLP-1 drugs for weight loss are and how they work

• The differences between Wegovy, Saxenda and Ozempic

• UK licensing and who they’re intended for

• Typical results, side-effects and safety issues

• Why prescription and proper monitoring are essential

Throughout, remember: these are prescription-only medicines in the UK, and this article doesn’t replace medical advice from your own doctor.

What are GLP-1 drugs – and how do they help with weight loss?

GLP-1 receptor agonists (often shortened to “GLP-1s”) are medicines that mimic a natural hormone called GLP-1 (glucagon-like peptide-1).

They were originally developed as diabetes meds, but some of them also produce meaningful weight loss, which led to specific weight management licences.

Mechanism in simple terms

GLP-1 drugs like semaglutide and liraglutide help with:

• Appetite control – they act on areas of the brain that regulate hunger and fullness, so you feel full sooner and have fewer cravings.

• Slower stomach emptying – food stays in your stomach longer, which prolongs satiety and smooths blood sugar rises after meals.

• Better blood sugar control – they increase insulin release when blood sugar is high and reduce glucagon, improving glucose levels in people with type 2 diabetes.

Because of this combination, GLP-1 for weight loss typically makes it easier to:

• Eat less without feeling as deprived

• Stick to a reduced-calorie diet

• Lose weight and improve metabolic health over time

Which GLP-1 drugs are used for weight loss in the UK?

The key names you’ll see are:

• Wegovy® (semaglutide) – licensed for weight management

• Saxenda® (liraglutide) – licensed for weight management

• Ozempic® (semaglutide) – licensed for type 2 diabetes, not for weight loss

• Semaglutide – the active ingredient in both Wegovy and Ozempic (and oral Rybelsus® for diabetes)

So when people talk about:

• “semaglutide weight loss” / “semaglutide for weight loss” → they usually mean Wegovy, which is semaglutide GLP-1 specifically licensed for weight management.

• “diabetes meds to lose weight” / “best diabetes drug for weight loss” → they’re often referring to GLP-1s developed for diabetes that also cause weight loss as a side-effect (like Ozempic), even though not all of them are licensed as weight loss drugs.

Wegovy vs Saxenda vs Ozempic: key differences

Below is a simplified comparison of the most commonly discussed GLP-1 medicines in the UK.

Always check the official patient leaflet and talk to a doctor or pharmacist for the most up-to-date details.

In other words:

• Wegovy and Saxenda = GLP-1 weight loss drugs in the UK.

• Ozempic and Rybelsus = GLP-1 diabetes medicines that can cause weight loss but are not licensed as weight loss treatments.

What does the evidence say about GLP-1 for weight loss?

Semaglutide (Wegovy) for weight loss

Large clinical trials (the STEP programme) looked at semaglutide 2.4 mg once-weekly in people with obesity or overweight plus comorbidities, alongside lifestyle changes:

• Average weight loss of around 15% of starting body weight over 68 weeks with Wegovy + lifestyle, compared with much less on lifestyle alone.

• A significant proportion of patients achieved ≥10% or ≥15% weight loss.

This is why semaglutide weight loss injections are often described as a major step-change in medical obesity treatment.

Liraglutide (Saxenda) for weight loss

Trials of liraglutide 3.0 mg daily showed:

• Average weight loss of around 5–8% of body weight over about 1 year, again combined with diet and exercise support.

• More patients reaching clinically meaningful weight loss thresholds compared with placebo.

Ozempic (semaglutide) in diabetes

Ozempic is studied and licensed for type 2 diabetes, not obesity, but:

• Diabetes trials show improved glycaemic control and weight loss compared with some other diabetes meds.

• Because of this, people sometimes see it as the “best diabetes drug for weight loss”, even though its primary goal is glucose control.

Across the GLP-1 class, research shows improvements not just in weight, but in blood sugar, blood pressure, lipids and cardiovascular risk markers for many patients.

Important: Clinical trial averages are not guarantees. Some people lose less, some don’t respond well, and a few cannot tolerate the medicine at all.

Who are GLP-1 weight loss drugs for in the UK?

UK rules are quite specific – especially on the NHS.

NHS use (Wegovy & Saxenda)

NICE recommends semaglutide (Wegovy) and liraglutide (Saxenda) for weight management only under certain conditions, typically:

• Adults with BMI ≥ 35 kg/m² plus at least one weight-related condition (for example, type 2 diabetes, high blood pressure, sleep apnoea), or

• Adults with BMI 30–34.9 kg/m² and similar risk factors, where they also qualify for a specialist weight management (Tier 3) service

• Lower BMI thresholds may apply for some ethnic groups because of higher risk at lower BMI.

NHS guidance usually limits:

• Where they can be prescribed (specialist clinics, not routine GP prescribing)

• How long they’re used (e.g. Wegovy often for up to 2 years, stopping if insufficient weight loss)

Private clinics

Private weight management services may offer Wegovy or Saxenda using the licensed weight loss indications, such as:

• BMI ≥ 30 kg/m², or

• BMI ≥ 27 kg/m² with at least one weight-related comorbidity

But even privately, a clinician still has to:

• Take a full medical history

• Check current medications and interactions

• Assess risks vs benefits

• Provide ongoing monitoring and support

GLP-1 drugs are not intended for people who just want to “drop a few pounds” for cosmetic reasons. Regulatory guidance stresses they should be reserved for those who are overweight or obese with health risks.

Side-effects, risks and safety

Common side-effects

Across GLP-1 medications, the most common side-effects are gastrointestinal:

• Nausea / feeling sick

• Vomiting

• Diarrhoea or constipation

• Abdominal pain, bloating or indigestion

• Loss of appetite (sometimes too strong)

• Headache, dizziness

• Injection-site reactions

These are often dose-related and may improve over time or with slower dose escalation.

More serious but less common risks

Important but less common issues include:

• Gallbladder problems and gallstones

• Pancreatitis (inflammation of the pancreas) – can be severe

• Possible worsening of diabetic retinopathy in some people with rapid improvements in blood sugar

• Concerns around delayed stomach emptying and anaesthesia, leading to new pre-surgery advice for some patients on GLP-1 RAs

• Potential interactions with oral contraception due to vomiting/diarrhoea reducing pill effectiveness.

Because of these risks, regulators in the UK repeatedly emphasise:

• Only use GLP-1 medicines under medical supervision

• Only for licensed indications

• Report side-effects through schemes like the MHRA Yellow Card.

“Ozempic without prescription”: why it’s unsafe and illegal

Searches like “Ozempic without prescription” or “buy Ozempic online UK” have exploded – but there are big problems here.

In the UK:

• Ozempic, Wegovy, Saxenda and other GLP-1s are Prescription-Only Medicines (POMs).

• That means they must be prescribed by an authorised prescriber and dispensed by a regulated pharmacy.

Getting them without a valid prescription, for example:

• From social media “sellers”

• From beauty salons or gyms

• From unregulated websites or overseas suppliers

is both illegal and high-risk, because:

1. You may not get the right drug or dose

   • Counterfeit and mislabelled injectables are a known problem globally.

2. No proper medical checks

   • No assessment of your BMI, medical history, other medicines, pregnancy plans or mental health.

3. No monitoring

   • No one to adjust dose, manage side-effects or decide when to stop.

4. No accountability

   • If something goes wrong, you have limited protection or recourse.

The UK government and MHRA have specifically warned about misuse, off-label use and supply of GLP-1s via unofficial routes, and emphasise that they should only be used for their licensed purposes.

If a site offers “cheap weight loss drug Ozempic with no questions asked”, treat that as a huge red flag.

Choosing between Wegovy, Saxenda and other options

You can’t – and shouldn’t – decide this alone. But it helps to understand the general differences:

• Wegovy (semaglutide weight loss)

  • Once-weekly semaglutide injection

  • Typically produces the largest average weight loss among the GLP-1 weight loss drugs, based on current evidence.

• Saxenda (liraglutide weight loss)

  • Once-daily injection

  • Long track record; weight loss averages are lower than with Wegovy, but still clinically meaningful.

• Ozempic (semaglutide for diabetes)

  • Once-weekly semaglutide injection

  • Licensed for type 2 diabetes; any use as a “diabetes weight loss drug” must still be within its diabetes indication and under proper supervision.

Your doctor or weight-management clinician will consider:

• Your BMI and health conditions

• Whether you have type 2 diabetes, pre-diabetes or other risks

• Past response to lifestyle changes and other treatments

• Safety considerations (kidney, liver, pancreatic, gallbladder, endocrine history, pregnancy plans)

• Your ability to attend follow-up and make parallel lifestyle changes

Often, the real question is not “What is the best diabetes drug for weight loss?” but “What is the safest, most appropriate overall plan for my health over the long term?”

Where to learn more next (internal links)

If your site has individual posts for each medicine, you can guide readers deeper:

• Wegovy deep-dive: indications, dosing, timelines and expected results
  → e.g. /blog/wegovy-weight-loss-guide

• Saxenda deep-dive: daily dosing, who it suits best, and pros/cons vs Wegovy
  → e.g. /blog/saxenda-weight-loss-liraglutide

• Ozempic & semaglutide deep-dive: diabetes focus, off-label questions and safety
  → e.g. /blog/ozempic-semaglutide-diabetes-and-weight-loss

Linking these from this GLP-1 overview hub helps users (and search engines) understand how your content fits together and find the specific answers they’re looking for.

Key takeaways

• GLP-1 drugs for weight loss (mainly Wegovy and Saxenda in the UK) work by reducing appetite, slowing digestion and improving blood sugar control.

• Semaglutide weight loss injections (Wegovy) can lead to ~15% average weight loss in trials, while Saxenda averages ~5–8% – but results vary and are never guaranteed.

• Ozempic is a semaglutide GLP-1 licensed for type 2 diabetes, not for obesity, even though it also causes weight loss.

• All GLP-1s carry gastrointestinal side-effects and rare but serious risks like pancreatitis and gallbladder disease, which is why doctor supervision is essential.

• Getting Ozempic without prescription or buying GLP-1s from unregulated sources is unsafe and illegal in the UK. Stick to regulated, prescription-only routes.

If you’re considering GLP-1 treatment, the safest next step is to speak with a regulated UK provider or your GP, discuss your health history in detail, and explore whether a GLP-1 medicine – combined with structured lifestyle support – is the right option for you.