The short version
- Work through the carton, the label, the pen and the liquid, in that order.
- A tirzepatide pen doses in milligrams. Anything showing insulin units is not tirzepatide.
- Batch numbers and barcodes can be copied from genuine packs, so they prove less than people think.
- Where the pen came from tells you more than how it looks.
Counterfeiters follow demand, and nothing in Nigeria is in more demand than tirzepatide. The checks below catch the crude fakes, which is most of them. They will not catch a good one, and it is important to be honest about that.
Start with the carton
- Manufacturer. Tirzepatide sold as Mounjaro is an Eli Lilly product. Look for the maker's name and address printed properly, not stuck on.
- Print quality. Blurred text, uneven ink, misaligned panels and thin card are all signals. Genuine cartons are sharply printed.
- Spelling and spacing. Read the whole carton, including the small print. Errors are common on fakes and almost unheard of on genuine packs.
- Tamper seals. Both ends should be sealed and unbroken. A carton that has been opened and reglued is a reason to stop.
- Language and market. Packs made for different markets look different. That alone does not mean fake, but it should prompt questions about the route it travelled.
Match the carton to the pen
- Strength. The dose on the carton and the dose on the pen label must be identical.
- Batch or lot number. Must match exactly between carton and pen label.
- Expiry date. Same on both, and in the future. Check the format is consistent across the pack.
- Label attachment. A label that is crooked, bubbled, peeling or clearly printed over another label is the single most damning sign.
The relabelling trick is real. In 2023 NAFDAC warned about falsified Ozempic pens circulating in Nigeria that were relabelled insulin pens. The counterfeit dosing scale ran from 0 to 80 units and extended outward when dialled, which no genuine Novo Nordisk semaglutide pen does. If a pen doses in units rather than milligrams, do not inject it.
The pen itself
- Dose display. Tirzepatide is dosed in milligrams. A display in insulin units means it is not what the label claims.
- Mechanism. The pen should behave exactly as the leaflet in the box describes. Read the leaflet before the first injection, not after.
- Build quality. Rough seams, loose caps, rattling parts and cheap plastic are all wrong.
- Needle fitting. Needles should attach cleanly and securely.
The liquid
It should be clear and colourless. Cloudiness, floating particles, colour or a pen that has clearly been frozen all mean do not use it, whether or not the pen is genuine.
What these checks cannot do
In 2024 NAFDAC passed on a warning about falsified Ozempic found at European wholesalers where the fakes carried batch numbers, 2D barcodes and serial numbers taken from genuine packs. If a counterfeiter copies real identifiers onto a convincing carton, no visual check will save you.
That is why provenance beats inspection. Knowing who held the pen, where it was stored and who is accountable if something is wrong protects you in a way that squinting at a carton cannot.
If something looks wrong
- Do not inject it.
- Keep the pen, the carton and the leaflet. They are the evidence.
- Photograph everything, including the batch number.
- Tell the seller the same day.
- Report it to NAFDAC on 0800-162-3322 or sf.alert@nafdac.gov.ng.
Our full counterfeit guide covers semaglutide pens as well, and the cold-chain questions that sit alongside authenticity.
Check Before You Inject
Ask us for the batch number and expiry before you pay, then match them against the pen when it arrives.
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