Yellow Card: reporting a reaction to an unlicensed product

If you have had a reaction to a product sold as retatrutide, you can report it to the MHRA through the Yellow Card scheme. It takes about ten minutes, it is confidential, it is not a police report, and it explicitly covers fake and unlicensed products. This page walks through what to report, what information helps, and how to report the seller too.

What the Yellow Card scheme is

The Yellow Card scheme is how the MHRA collects reports of suspected problems with healthcare products from the public and from health professionals. Every report goes into a database that the agency searches for patterns. A single report rarely proves anything; a cluster of similar reports is a signal, and signals are what trigger investigations, warnings and recalls.^[1]

The scheme is not only for licensed medicines. The MHRA's own guidance says you can report "side effects, defective products (not of an acceptable quality), and falsified or fake healthcare products", and it has a specific category for "fake/unauthorised medicines", defined as a product passing itself off as a genuine medicine or one that does not hold a UK licence.^[2] A product sold as retatrutide fits that description exactly, because retatrutide holds no licence anywhere.

What you can report

• A side effect. Anything you think the product may have caused, whether or not you are sure. Nausea, a rash, palpitations, an injection-site infection, a liver problem picked up on a blood test.
• A suspected fake or unauthorised product. Including one that did nothing at all, since a product with none of the stated drug in it is as much a safety problem as one with too much.^[2]
• A defective product. Cloudy liquid, particles, a damaged seal, a leaking pen.
• Something that happened to someone else. You can report on behalf of a friend or family member.^[4]

You do not need to be certain that the product caused the problem. The scheme runs on suspicion; working out cause is the MHRA's job.

How to report, step by step

1. Go to the Yellow Card website or open the Yellow Card app, which is free on the Apple and Google Play app stores.^[1][3] You can report as a guest without an account.
2. Search for the product. Retatrutide will not appear as a licensed product, so type the name as it appeared on your label, or choose the option for a product that is not listed.
3. Describe what happened: the symptoms, when they started, how long they lasted, and what you did about it.
4. Give what you know about the product: what the label said (name, stated strength, any batch number), whether it was a vial or a pen, and roughly where it came from, for example "a website", "a social media seller" or "a friend". You do not have to name anyone.
5. Add some basic details about yourself: age, sex, and any other medicines or conditions. These help the MHRA judge whether the reaction fits a pattern.
6. Submit. You will get a reference number. If you made an account, you can track your report and add to it later.

The MHRA may contact you for more information, and may ask for a sample of the product if you still have it.

What information helps most

• A photo of the vial or pen and its label, including any batch or lot number. Fake products often share batch numbers across many sales, which helps the MHRA link reports.
• Dates: when you first used it, when the symptoms started, when they stopped.
• What the label claimed: drug name, strength, and anything like "research use only".
• Where it came from in general terms. Website, social media app, messaging group, in person. You can give a URL or account name if you want to; it is not required.
• What happened next: NHS 111 call, GP visit, A&E, blood-test results, diagnosis.
• Keep the product if you safely can. Do not throw the vial away until you know whether anyone wants it.

Confidential, and not a police report

The MHRA is a medicines regulator, not a police force. Its privacy policy says it will not share your personal data with anyone outside the agency unless it is required or permitted to do so by law, and that research access to Yellow Card data is reviewed by an independent committee to protect reporter confidentiality.^[4]

There is also nothing to report you for. Retatrutide is not a controlled drug under the Misuse of Drugs Act, so possessing it is not an offence.^[7] The law that applies, the Human Medicines Regulations 2012, targets the people who sell, supply and advertise unlicensed medicines, not the people who use them.^[8] The legal page goes through this in more detail.

Why reporting matters even for an unlicensed product

It is easy to assume that reporting a reaction to a product that was never legal is pointless. The opposite is true.

Signal detection. Nobody is monitoring these products except the people who use them. The trials tell us what retatrutide does; they cannot tell us what an unlicensed vial of unknown content does. Yellow Card is the only place those reports are gathered. In 2023, 16 reports about fake weight-loss pens were enough for the MHRA to confirm that five contained insulin and to issue a national warning.^[5]

Enforcement. Reports feed the MHRA's Criminal Enforcement Unit, which seized nearly 20 million doses of illegal medicines in 2025 and disabled more than 1,500 websites and social-media accounts.^[9] The enforcement page covers the retatrutide raids.

Research. The MHRA and Genomics England run the Yellow Card Biobank, which is studying whether genetics affect the risk of acute pancreatitis in people taking GLP-1 medicines. It recruits people who were admitted to hospital with pancreatitis after a GLP-1 drug. That kind of study only exists because people reported.^[10]

Your own record. A Yellow Card reference is something you can give your GP, and it dates your account of events.

Reporting a seller

Separately from Yellow Card, you can report a website or online seller that you think is offering medicines illegally. GOV.UK runs a dedicated service that goes to the MHRA. Anyone can use it and you can do it anonymously. It asks why you are reporting and for the seller's website address or social-media name; you can add photos of the product and packaging, screenshots, receipts or messages if you have them.^[6]

This route is for the seller, not for your health. If you have had a reaction, use Yellow Card as well.

Reporting harmful content

If the problem is a post, video or account rather than a seller, for example someone promoting products to teenagers or sharing dangerous advice, Report Harmful Content is a UK service run by SWGfL with the UK Safer Internet Centre. It explains the reporting routes for each major platform and can escalate reports that a platform has ignored.^[11] Most platforms also have their own route for reporting the sale of regulated goods.

Where to get help for symptoms

Reporting comes after safety. If you are unwell now, use the routes below. When to seek help explains which symptoms need which service.