What is compounded semaglutide?

When you buy Wegovy online, it's important to make sure you're dealing with a legitimate provider that supplies the genuine, licensed medication via a valid prescription.

The UK's medicines regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), has warned against sellers offering fake and illegal weight loss injections online.¹ These counterfeit products may contain the wrong ingredients – or none at all – and can pose serious health risks.

Alongside these illegal products, you might also come across compounded semaglutide. This is an unlicensed preparation of the active (main) ingredient found in Wegovy.

When prescribed and supplied properly, compounded medicines are legal in the UK. However, they haven't gone through the same approval and testing process as the licensed medication.

In this quick guide, we take a closer look at compounded semaglutide. What is it, how is it different from licensed Wegovy, and what should you know before starting treatment?

What is compounded semaglutide?

Wegovy is a licensed medication in the UK. That means it's been tested and the UK's medicines regulator has approved its use.

Compounded semaglutide is an unlicensed version of semaglutide – the active ingredient in Wegovy. Unlike licensed Wegovy, which is manufactured at a large scale by Novo Nordisk, compounded semaglutide should be made specifically for individual, named patients.

This can be legal. In the UK, doctors may prescribe an unlicensed medication (a 'special') if they believe a licensed product isn't suitable for a particular patient. They must supply this unlicensed medication against a valid prescription.

However, because it's unlicensed, compounded semaglutide hasn't gone through the same testing and approval process as licensed Wegovy.

It's also not supposed to be advertised directly to the public. So, if you see compounded semaglutide promoted like a normal retail product, that may raise questions about whether the seller is following the rules.

Are unlicensed medications dangerous?

Unlicensed drugs are not inherently dangerous if they're made and supplied according to UK medicine rules.

However, there are important differences between licensed and unlicensed drugs that are worth keeping in mind:

• They haven't been tested and approved in the same way as licensed medications. Licensed drugs are backed by large clinical trials and are closely monitored for safety. While unlicensed medications are regulated, they're not regulated to the same standards.
  
  
• They're not made to a fixed, approved formula. They may follow a different recipe from the 'real thing', and might not have exactly the same effects.
  
  
• They can't be advertised directly to the public. Clinics and pharmacies can promote licensed medications in accordance with strict UK advertising rules. However, they're not allowed to promote unlicensed medications at all.
  
  

How to stay safe when buying semaglutide online

As we've seen, compounded semaglutide isn't automatically unsafe or illegal. In some cases, doctors can prescribe an unlicensed drug if there's no suitable licensed alternative.

However, in the UK, unlicensed medicines should not be advertised directly to the public.

So, if you see a seller openly promoting compounded semaglutide on a website, Instagram page or Facebook ad, that's a big red flag. It raises questions about:

• Whether what you'll receive really contains semaglutide
• Whether the supplier is following UK medicine regulations
• Whether the product has been made and stored correctly
• Whether the supplier is prescribing the medication with proper medical oversight
  
  

Our advice: think hard before you buy. The safest way to access semaglutide in the UK is to get a valid prescription from an NHS doctor or legitimate private healthcare provider. That means one that:

• Requires a full medical consultation and provides a prescription
• Supplies licensed Wegovy in clear, branded packaging
• Is registered with the General Pharmaceutical Council
• Has a named team of medical experts overseeing your care
  
  

And remember to shop smart. That means taking a moment to think and asking 'Does this look right?', and 'Is this too good to be true?'. When your health and well-being are at stake, you can never be too careful.

Semapen is a UK-based weight loss clinic and NHS partner led by a multidisciplinary team of obesity and diet specialists.

We're registered with the CQC and the General Pharmaceutical Council, and as part of Phoenix Health, we've helped people lose weight for over 20 years. Learn more about our expert-led weight loss programmes.

Sources

1. The Medicines and Healthcare products Regulatory Agency (2023) MHRA warns of unsafe fake weight loss pens. [press release] Retrieved from https://www.gov.uk/government/news/mhra-warns-of-unsafe-fake-weight-loss-pens

This article was reviewed and approved by Lujain Alhassan, Bariatric Nutritionist, on 28 February 2026.