Healthy weight loss takes time, not shortcuts. As demand for weight-loss medicines continues to rise, the MHRA is reminding people how to use GLP-1 medicines safely, spot illegal sellers and avoid diet changes that could interfere with their medicines
With prescription weight loss medicines being advertised illegally on social media alongside quick-fix slimming claims, the Medicines and Healthcare products Regulatory Agency (MHRA), warns Brits to not let summer slimming put their health at risk.
From over-dosing on prescription weight-loss meds to buying dangerous fakes online, the MHRA reveals the mistakes that could leave you seriously ill, and the simple steps to lose weight safely.
1. Follow doctor’s orders if you are prescribed a GLP-1
If you’ve been prescribed a GLP-1 weight-loss medicine, don’t be tempted to fast-track your weight loss by upping your dose. Semaglutide (Wegovy), tirzepatide (Mounjaro) and liraglutide (Saxenda) should only be taken as prescribed by a healthcare professional.
Follow doctors’ orders and take your prescribed GLP-1 alongside a healthy diet and a fitness regime. Whether you’re taking it for diabetes management or weight loss, maintaining good nutrition and exercise can help support muscle, bone, and overall health as your calorie intake changes.
2. Steer Clear of Fake Weight-Loss Meds
If you’re not eligible for a prescription for weight-loss medicines, don’t be tempted to buy them from unregulated websites or social media sellers. GLP-1 medicines authorised in the UK have only been shown to be safe and effective for people with a Body Mass Index (BMI) of 27 or more. Buying from rogue sellers is a huge risk. You can’t be sure what’s in the product, and some fake medicines are contaminated with toxic substances.
Don’t be tempted by the online hype around retatrutide. It has not been authorised for use in the UK, meaning anyone selling this product is doing so illegally. These products haven’t been tested for safety, quality or effectiveness and there’s no guarantee that they even contain retatrutide. You could be putting your health at serious risk.
Head of the MHRA’s Criminal Enforcement Unit, Andy Morling, said: “Rogue sellers are driven by profit, not your safety, and the fake medicines they sell could put your health at serious risk.
“These products may not contain the GLP-1 medicine you think you’re buying and could be contaminated with bacteria and other harmful substances.
“Be wary of deals that seem too good to be true and check the pharmacy is registered with the General Pharmaceutical Council. The simple rule for staying safe is that if you’re offered a GLP-1 medicines without the need for a prescription – walk away.”
3. Check Your Meds Before Changing Your Diet
Trying to eat more healthily before your holiday? Great – but make sure your diet doesn’t clash with your medication. Always read the patient information leaflet before making dietary changes, as some foods could compromise medicines’ effectiveness. People taking simvastatin to lower their cholesterol should avoid grapefruit and grapefruit juice as they slow the rate the body breaks down the medicine, increasing the risk of serious side effects.
Thinking about intermittent fasting? Remember that some medicines need to be taken with food to work most effectively and lower your risk of side effects. Metformin, used to treat diabetes, and the painkiller naproxen should both be taken with or after food to help prevent stomach upset.
MHRA’s Chief Safety Officer, Alison Cave said: “There’s no shortcut to safe weight loss. If you’re trying to slim down, follow medical advice, avoid fake medicines and remember that healthy eating and regular exercise are still the safest ways to get in shape for summer.”
Counterfeit Weight-Loss Pills Could Be the Next Online Health Scam
Pharmacist reveals the warning signs that a weight-loss medicine may be fake as the first GLP-1 tablet is approved in the UK
Consumers are being warned to watch for fake weight-loss tablets appearing on social media and unregulated websites following the approval of the first oral GLP-1 medicine for weight management in the UK.
The Medicines and Healthcare products Regulatory Agency approved the semaglutide tablet for weight loss on 11 June 2026, creating a needle-free alternative to injectable treatments.
However, Sobia Qasim, Superintendent Pharmacist at Curely, warns that growing public interest in weight-loss pills could also create a new opportunity for illegal sellers.
Unlike injectable pens, tablets can be placed in ordinary bottles, blister packs or envelopes and posted without specialist equipment, potentially making counterfeit products appear more convincing to consumers.
Fake medicines may contain the wrong dose, no active ingredient or entirely different and potentially harmful substances. The MHRA has already uncovered organised criminal networks manufacturing illegal weight-loss medicines and seized almost £45 million worth of illegal medicines during 2025.
Sobia said: “The arrival of an approved weight-loss tablet is an important development for patients, particularly those who are uncomfortable with injections. However, high demand and widespread online interest can also attract illegal sellers looking to exploit people who want quick or cheaper access.
“A tablet may look less suspicious than an injection because consumers are accustomed to receiving pills through the post. But a professional-looking box, blister pack or website does not prove that the medicine is genuine.
“Prescription weight-loss medication should only be supplied after an appropriate clinical assessment by a qualified healthcare professional. Any seller willing to bypass that process should immediately raise concern.”
Seven signs a weight-loss pill could be fake
| Warning sign | Why it should raise concern |
| It is sold through social media messages | Genuine prescription medicines should not be bought through private messages, marketplace listings or informal social media accounts. |
| No medical consultation is required | Weight-loss medication is not suitable for everyone. A regulated provider should assess your health, current medicines and eligibility before prescribing it. |
| The seller guarantees a specific amount of weight loss | Results differ between patients. Guaranteed outcomes are a marketing tactic, not responsible clinical advice. |
| You are pressured to act quickly | Countdown timers, limited stock claims and urgent payment requests may be used to stop consumers checking whether a provider is legitimate. |
| The price appears unusually low | A price substantially below recognised providers may indicate that the medicine is fake, unlicensed, incorrectly stored or obtained illegally. |
| The tablets arrive loose or in unfamiliar packaging | Medicines should arrive in sealed, labelled packaging with clear dosage information and a patient information leaflet. |
| There is no registered pharmacy information | Consumers should be able to identify the pharmacy supplying the medicine and verify that it is registered with the appropriate UK regulator. |
A familiar brand name does not guarantee a genuine product
Sobia warns that counterfeiters may copy recognised brand names, logos, batch numbers and packaging to make illegal products appear authentic.
In February 2026, the MHRA confirmed that a falsified version of a Mounjaro injection had been supplied through an online pharmacy in the UK. The regulator said fake medicines may contain incorrect ingredients, no active ingredient or harmful substances.
Previous fake GLP-1 injections discovered in the UK have also contained insulin, creating a risk of dangerously low blood sugar for people who unknowingly used them.
Sobia continued: “Counterfeiters can reproduce colours, logos and packaging extremely convincingly. Consumers should never judge a medicine by appearance alone.
The checks around the medicine are just as important as the product itself. Who prescribed it? Was a proper consultation completed? Which registered pharmacy supplied it? Can you contact a healthcare professional if something goes wrong?
“If those questions cannot be answered clearly, do not take the tablets.”
What consumers should check before ordering
Before purchasing weight-loss medication online, Curely recommends checking that:
- Genuine clinical assessment is required
- Qualified prescriber reviews the order
- The dispensing pharmacy is registered in the UK
- The provider asks about existing health conditions and medication
- Clear contact details are available
- The medicine arrives sealed and properly labelled
- Instructions and patient safety information are included
- Follow-up support is available throughout treatment
The NHS warns that medicines bought from unregistered websites may be out of date, diluted, fake or unsuitable for the person taking them.
What to do if you think a weight-loss medicine is fake
Anyone who believes they have received a counterfeit or suspicious medicine should not take another dose until they have spoken to a pharmacist or doctor.
Consumers should keep the packaging, receipt and details of the website or seller. Suspected fake medicines and side effects can be reported through the MHRA Yellow Card scheme.
Those who experience severe or persistent abdominal pain, repeated vomiting, difficulty breathing, loss of consciousness or symptoms of dangerously low blood sugar should seek urgent medical assistance.
Sobia added: “People may feel embarrassed if they have bought medication from an unofficial seller, but healthcare professionals need to know exactly what may have been taken so they can provide the right treatment.
Do not throw the packaging away and do not assume that feeling unwell is simply a normal side effect. With an unregulated product, there is no reliable way to know what the tablet contains or what dose has been supplied.
The safest route is always a properly regulated service offering clinical assessment, genuine medication and ongoing professional support.”
