Fake and Unlicensed Weight Loss Jabs: How to Spot Them

Fake and unlicensed weight loss jabs are products sold as, or in place of, licensed medicines such as Mounjaro (tirzepatide) and Wegovy (semaglutide), but which have not been made, approved or supplied through the regulated system. You can usually spot them by where they come from (social media, salons, "research peptide" websites or anyone supplying without a prescription), how they look (vials of powder, unbranded pens, missing UK leaflets, "research use only" labels) and how they are sold (no consultation, very low prices, pressure to act quickly). The Medicines and Healthcare products Regulatory Agency (MHRA) has seized large quantities of these products in the UK. This guide explains the warning signs, the risks, and what to do if you have used one. It sits within our safety guides, part of our wider library of GLP-1 guides.

What counts as a "fake" or "unlicensed" weight loss jab?

People use the word "fake" loosely. It helps to separate a few categories, because the risks differ slightly.

All of these are outside the regulated system. Even in the last category, where the product may be genuine, the lack of assessment, unknown storage conditions and absence of aftercare create real risks.

What has the MHRA found?

The MHRA's Criminal Enforcement Unit investigates illegal medicine supply in the UK. Weight-loss products have become a major focus.

In October 2025, the MHRA announced it had dismantled an illicit production facility in a Northampton warehouse, describing it as the first such facility for weight-loss medicines found in the UK, and believed to be the largest single seizure of trafficked weight-loss medicines recorded by a law enforcement agency worldwide. Officers seized:

• More than 2,000 unlicensed retatrutide and tirzepatide pens awaiting dispatch
• Tens of thousands of empty pens ready to be filled
• Raw chemical ingredients and manufacturing equipment

In February 2026, the MHRA reported disrupting a second suspected manufacturing operation, at premises in Lincolnshire and Nottinghamshire, seizing almost 2,000 doses of unauthorised weight-loss medicines, including products described as retatrutide and tirzepatide, along with manufacturing equipment and packaging. It has also issued repeated public warnings against obtaining weight-loss medicines from unregulated sources.

These cases show that fake products are not limited to crude knock-offs. Some are made at scale, in pens designed to resemble legitimate products, and sold through slick websites and social media accounts.

Why fake jabs have become more common

Several factors have combined to create a market for illegal weight-loss products:

• High demand. GLP-1 medicines have received huge public attention, and clinical trial results such as SURMOUNT-1 (tirzepatide) and STEP 1 (semaglutide) showed average weight loss well beyond what earlier medicines achieved.
• Limited NHS access. NICE has recommended both semaglutide (TA875) and tirzepatide (TA1026), but NHS access is restricted to people meeting specific criteria and is being phased in. Many people who would like treatment cannot get it on the NHS.
• Cost. Private treatment is self-funded, and costs rose for some medicines after Lilly increased the UK list price of Mounjaro from September 2025. Illegal sellers exploit this by advertising lower prices.
• Eligibility. People who do not meet the licensed BMI criteria, or who have been turned down by a legitimate service for safety reasons, may look for routes that avoid assessment.
• Social media. Short videos and influencer content can make injections seem casual and routine, and illegal sellers use the same platforms to reach people.
• Interest in unlicensed medicines. Publicity about investigational medicines such as retatrutide has created demand for products that cannot legally be supplied.

Understanding these pressures can help you recognise when an offer is designed to exploit them.

How illegal sellers market their products

Illegal sellers often use tactics that look professional at first glance. Common approaches include:

• Imitating legitimate brands, using similar colours, fonts and pen designs to genuine products
• Using "wellness" or "peptide" branding to avoid the language of medicines
• Offering "consultations" that are not real assessments, such as a brief form that approves everyone
• Promoting "microdosing", a term used to sell small, unlicensed doses outside any clinical framework
• Using testimonials and before-and-after photos, which cannot legally be used to promote prescription-only medicines to the public
• Creating urgency with countdown timers, "restocks" or limited-time prices
• Moving conversations to private messages, where there is no public record

The Advertising Standards Authority (ASA) has also taken action against registered pharmacies for promoting weight-loss prescription-only medicines to the public, which shows that even legitimate businesses can cross the line. For patients, the safest approach is to treat any promotional pressure around these medicines with caution.

Where fake and unlicensed jabs are sold

Most fake and unlicensed products reach people through channels outside the pharmacy system:

• Social media: Instagram, TikTok, Facebook, Snapchat and similar platforms, often through accounts that look like wellness brands or influencers.
• Messaging apps: WhatsApp, Telegram and private groups.
• "Peptide" websites: sites selling chemicals labelled "for research use only".
• Beauty, aesthetics and fitness settings: salons, aesthetic clinics without a registered prescriber, gyms and personal trainers.
• Unregistered websites: sites without registered pharmacy details, or overseas sites shipping prescription-only medicines without a UK prescription.
• Informal sharing: friends, family or colleagues passing on their medicine.

How to spot a fake: the product

Genuine Mounjaro

In the UK, Mounjaro is supplied as the KwikPen, a multi-dose pre-filled pen, according to the UK SmPC at the time of writing. A genuine supply should include:

• Branded outer carton with the medicine name, strength and manufacturer (Eli Lilly)
• Batch number and expiry date printed on the carton and pen
• A patient information leaflet in English
• Instructions for use
• A pharmacy dispensing label with your name, the medicine, dose, directions and the pharmacy's details

Genuine Wegovy

Wegovy injection is supplied as the FlexTouch pen by Novo Nordisk, with branded carton, batch and expiry details, an English leaflet and a pharmacy dispensing label.

Warning signs

If anything looks wrong, don't use the product. Contact the pharmacy and ask a pharmacist to check it.

How to spot a fake: the seller

The way a product is sold is often the clearest warning sign:

• No consultation, or only a token questionnaire with no verification
• No registered pharmacy details on the website, or details that don't match the GPhC register
• No named prescriber
• Payment by bank transfer, cryptocurrency or through messaging apps
• Very low prices, bulk deals or "starter packs"
• Urgency: countdown timers, "limited stock", "last chance"
• Before-and-after images and testimonials, which legitimate pharmacies cannot use to promote prescription-only medicines
• Offers of doses or medicines outside the licence, such as retatrutide or "microdosing" kits

Our guide to how to choose an online pharmacy for weight loss treatment explains how to check a seller is registered.

Why fake jabs are dangerous

Unknown contents

Products made outside regulated manufacturing may contain the wrong substance, the wrong amount of active ingredient, no active ingredient at all, or impurities. Without regulated manufacturing and testing, there is no way to know what is in a pen.

Dosing errors

A product containing more active ingredient than stated can cause severe nausea, vomiting, dehydration and, in people taking diabetes medicines, dangerously low blood sugar. Self-mixing powder vials adds further scope for error.

Infection and contamination

Injectable medicines must be sterile. Products made in unlicensed facilities may contain bacteria or other contaminants, leading to injection-site infections, abscesses or more serious infection.

Allergic reactions

Unknown ingredients or impurities can trigger allergic reactions, including severe ones.

No assessment, no aftercare

Even a genuine product taken without assessment can be harmful. GLP-1 medicines should not be used in pregnancy, and need careful thought in people with a history of pancreatitis, gallbladder disease, eating disorders, or diabetic eye disease. Our guide to who should not take GLP-1 medicines explains why. Illegal sellers do not check any of this, and offer no support if something goes wrong.

Difficulty getting the right treatment

If you become unwell after using an unknown product, doctors may not know what you have taken, which can make treatment harder.

Retatrutide and other unlicensed medicines

Retatrutide is an investigational medicine that acts on three hormone receptors (GIP, GLP-1 and glucagon). It has produced substantial weight loss in clinical trials, which has driven illegal demand. At the time of writing it is not licensed in the UK, and the MHRA has seized unlicensed retatrutide pens. Anything sold as retatrutide outside an approved clinical trial is unlicensed, and its contents cannot be trusted. Check the MHRA website for any change in its status.

Other investigational medicines may also be marketed illegally as they attract attention. Our guide to future GLP-1 treatments explains which medicines are in development and their status.

What about "compounded" or "generic" versions?

In some countries, pharmacies have produced compounded versions of semaglutide or tirzepatide during shortages. This is not a legitimate route in the UK, and there is no licensed generic tirzepatide or semaglutide for weight loss in the UK at the time of writing. A UK seller offering "compounded" or "generic" versions should be treated with suspicion.

Can fake pens reach registered pharmacies?

The regulated supply chain, with licensed wholesalers and anti-counterfeiting measures, makes this much less likely. However, problems have occasionally been reported in UK pharmacy news. If something about your pen looks different from previous supplies, or from the description in the leaflet, contact the pharmacy before using it, and report your concerns to the MHRA. If you are worried about a pharmacy's conduct, you can raise concerns with the General Pharmaceutical Council (GPhC).

Safer routes to treatment

The safe route is a registered prescriber, a genuine consultation and a registered pharmacy. That means:

• Checking the pharmacy on the GPhC register (or the PSNI register in Northern Ireland)
• Expecting identity checks, independent weight verification and detailed health questions (GPhC guidance since February 2025 says prescribing should not rely on a questionnaire alone)
• Receiving a licensed, branded product with a UK leaflet and pharmacy label
• Having access to clinical advice throughout treatment

Our guides to getting weight loss injections online safely and who regulates online weight loss services explain these steps.

The NHS also offers GLP-1 treatment to people who meet NICE criteria (NICE TA875 for semaglutide and TA1026 for tirzepatide), though access is phased and limited.

Our providers page explains how we compare regulated services on safety features and process. You can see what affects the cost of treatment from regulated services on our prices page, which also explains why prices that look unusually low should prompt questions.

What to do if you suspect a fake

1. Don't use it. If you haven't injected it yet, stop.
2. Keep the product and packaging, including any delivery documents and the website or account you used.
3. Report it to the MHRA through the Yellow Card scheme (yellowcard.mhra.gov.uk), which accepts reports of suspected fake medicines as well as side effects.
4. Contact the seller if it claims to be a pharmacy, and check its registration.
5. Report a pharmacy to the GPhC if you have concerns about a registered pharmacy.
6. Speak to your GP or pharmacist about safe treatment options.

What to do if you have already used one

• Stop using the product.
• If you feel unwell, seek medical advice, telling the clinician exactly what you used and where it came from. Bring the packaging if possible.
• Watch for signs of infection at injection sites: spreading redness, heat, swelling, pus or fever.
• If you have diabetes, check your blood sugar more often and seek advice on any medicines that may need adjusting.
• Report what happened to the MHRA through the Yellow Card scheme, even if you feel well. Reports help the regulator track and tackle illegal products.

Checking a delivered pen: step by step

If you have received your medicine from a registered pharmacy, it is still sensible to check it before your first injection:

1. Check the pharmacy label. It should show your name, the medicine, the strength, directions and the pharmacy's name and address.
2. Check the carton. It should be sealed, in English, and show the medicine name, strength, manufacturer, batch number and expiry date.
3. Check the pen. Compare it with the pictures and description in the instructions for use. The strength on the pen should match your prescription.
4. Check the leaflet. A patient information leaflet should be included.
5. Check the temperature. Pens should arrive cool, in insulated packaging. If the package is warm or delayed, contact the pharmacy before using it.
6. Check consistency. If anything differs from previous supplies, such as colour, labelling or pen design, ask the pharmacy to explain before you inject.

If something doesn't look right, don't use the pen. Contact the pharmacy and keep the product and packaging.

Talking to friends or family about unregulated products

You may know someone who is using injections bought through social media or from an unregistered seller. Conversations like this can be sensitive. Some approaches that may help:

• Focus on safety rather than judgement. Many people simply don't realise the risks.
• Share factual information, such as the MHRA's warnings and the signs of a fake product.
• Explain that legitimate treatment involves an assessment for good reasons, including checking for pregnancy, past pancreatitis and eating disorders.
• Encourage them to speak to their GP or a pharmacist about safe options.
• If they feel unwell, encourage them to seek medical help and to tell clinicians exactly what they have used.

When to speak to a professional

Speak to a pharmacist or GP if you are unsure whether a product is genuine, or if you want to discuss legitimate treatment options. Prescribing decisions belong to a qualified prescriber.

Seek medical help as follows if you have used a suspected fake or unlicensed jab:

• Call 999 or go to A&E if you have difficulty breathing, swelling of the face, lips, tongue or throat, collapse or confusion, severe and persistent abdominal pain (with or without vomiting), or symptoms of very low blood sugar such as shaking, sweating and confusion that do not improve with sugary food or drink.
• Contact NHS 111 or your GP urgently if you have persistent vomiting or diarrhoea, signs of dehydration (dark urine, dizziness, passing very little urine), a hot, red, swollen or painful injection site, or fever.
• Contact your GP about any other symptoms that worry you, and to discuss safe next steps.