Yellow Card action / O-048
How to report a suspected peptide medicine problem
Suspicion is enough to report. Give the MHRA the product, batch, source, timeline and outcome without claiming causation you cannot establish.
Use the MHRA Yellow Card scheme to report a suspected side effect, defective medicine or fake healthcare product. You do not need proof that the product caused the event. Include the exact label, batch, seller, timing, symptoms, other exposures and outcome. Yellow Card does not replace urgent medical care.
Call 999 for life-threatening symptoms or use NHS 111 for urgent advice. The Yellow Card service cannot diagnose or treat you.
Submit a clear, useful report
- 1
Deal with urgent symptoms
Seek emergency or urgent medical care before completing a report.
- 2
Gather the minimum product record
Collect the exact label, batch, source, dates, symptoms, other medicines and outcome.
- 3
Choose the Yellow Card category
Report the suspected side effect, defective medicine or fake healthcare product.
- 4
Describe facts and suspicion separately
Give the timeline and state that the causal link is suspected unless a clinician or regulator has established it.
- 5
Keep your reference and evidence
Retain the report confirmation, packaging and transaction records without unsafe handling.
Information worth including
| Record | Useful detail |
|---|---|
| Product | Exact wording, stated ingredient, form, strength, batch, expiry and photographs. |
| Source | Pharmacy, website, social account, seller details, order date and delivery. |
| Exposure | Date and time, route if known, and any other products used. |
| Event | Symptoms in sequence, seriousness, medical care, tests and treatment. |
| Outcome | Recovered, ongoing, admitted or other known outcome. |
| Reporter | Contact details requested by the scheme and whether a healthcare professional can add information. |
What a Yellow Card can and cannot do
It can add a suspected event to surveillance
The MHRA combines reports to look for signals, assess product defects and investigate fake products. A detailed batch and source record can make the report more useful.
It cannot prove your individual cause
A spontaneous report does not establish causation or incidence. It also does not provide personal medical advice or a legal determination about the seller.
For possible illegal online supply, use the route for illegal sellers instead.
Our causality rule
We use “reported after”, “suspected” or “reported in association with” until a regulator or suitable evidence supports a causal claim. The product identity and reporting limitations stay inside the same paragraph as the event.
Yellow Card questions
Can I submit a Yellow Card for an unlicensed or fake product?
The MHRA accepts reports about suspected medicine side effects, defective medicines and falsified or fake healthcare products. Give the product and source details available, even when identity is uncertain.
Do I need to prove that the product caused the reaction?
No. The MHRA states that you need suspicion, not proof of causality. Describe what happened, the timing and competing exposures without presenting your suspicion as a confirmed cause.
Can I report without internet access?
Current MHRA guidance gives a free telephone route on 0800 731 6789, Monday to Friday, 9am to 5pm, for patients without online access.
Does Yellow Card provide medical advice?
No. The Yellow Card service collects safety reports and does not provide medical advice. Contact a clinician or NHS 111 if you are worried, and use 999 for emergency symptoms.
Official sources
- MHRA Yellow Card schemeAccessed 7 August 2026
- MHRA Yellow Card guidanceAccessed 7 August 2026
- What to report to Yellow CardAccessed 7 August 2026
- Why peptide reports matterAccessed 7 August 2026
Editorial experience
From our work: how we checked this page
For topical-map item O-048, How to report a suspected peptide medicine problem was checked as a distinct editorial task, not treated as a generic peptide page. We reviewed 3 unique external sources and 6 internal destinations in the page, then checked that the opening answer, headings, source descriptions and linked next steps stayed within the same claim boundary. The count records links in the published page and is not a claim that every source carries equal evidential weight.
Yianni Kiromitis checked the page against its mapped purpose, verified the cited sources, reviewed the internal routes and approved the final wording as Lead Author, Publisher and Managing Editor. This page does not carry a specialist review credit because its publication decision did not require a scientific or clinical conclusion beyond the named material it links to.
We did not use patient experience, a personal treatment outcome, seller testimony or an assumed product identity to support this page. The publication did not independently test a vial for this review. Where a page refers to a laboratory result, that result applies only to the named sample, method and attribute. We kept uncertainty beside the conclusion, recorded which source supports each material claim, and checked that the visible review date matches the publication record. A new controlled study, regulator update, corrected source, analytical report or credible safety signal can trigger reassessment through the public correction route.