How to spot fake GLP-1 pens: warning signs and how to check

Why are fake GLP-1 pens a concern?

Because regulators on several continents have found them, including inside the regular supply chain. WHO says falsified Ozempic was "supplied in the regulated supply chain", and the US FDA found counterfeits "in the legitimate U.S. drug supply chain".

WHO warns that using falsified Ozempic "may result in the ineffective treatment of patients due to incorrect dosage, contamination with harmful substances, or use of unknown or substituted ingredients." Because the pens are injected under the skin, WHO adds that it may pose other serious risks "that could be life-threatening."

These are the incidents reported by the regulators used for this page:

Which lot and serial numbers did regulators flag?

These are examples published by regulators for the US, UK and Brazil markets. They are not a list of every fake, and packs sold in the Philippines may look different.

So a real batch or lot number alone does not prove a pen is genuine. WHO and the US FDA both list numbers that are genuine on their own.

What are the warning signs on the pen and pack?

WHO and the US FDA describe physical signs, based on the fakes they examined.

WHO (Medical Product Alert N°2/2024):

• Lot and serial number. Check them against the numbers WHO lists for the affected batches.
• The pen. Falsified Ozempic pens "may have a scale extending out from the pen when setting the dose."
• The label. It "might be of poor quality and may not adhere well to the pen."
• The carton. It "may have spelling mistakes on the front of the box."

US FDA (December 2025 update):

• On the counterfeit pens labelled lot PAR1229, the "EXP/LOT" text sits to the left of the expiry date and lot number. On the authentic Ozempic pen, it sits above them.

EMA (October 2023):

• Compare your pen with the patient information leaflet to see what the genuine pen should look like.
• EMA said the falsified pen looked different from the original, and that falsified pens "with other features are also likely."

A pen can pass all of these checks and still be fake. These signs only describe the fakes regulators have seen so far.

What were fake pens found to contain?

Not what the label said, in the cases regulators described.

• Insulin instead of semaglutide. The UK MHRA reported a very small number of hospitalisations after use of potentially fake pens. Serious side effects, "including hypoglycaemic shock and coma, indicate that the pens may contain insulin rather than semaglutide," it said.
• Counterfeit needles. The US FDA found the needles in its 2023 samples were counterfeit, so "the sterility of the needles cannot be confirmed," which raises the risk of infection.
• Unknown contents in general. The US FDA says counterfeit drugs "could contain the wrong ingredients, contain too little, too much or no active ingredient at all or other harmful ingredients."

The Philippine Pharmacy Act (RA 10918) defines counterfeit pharmaceutical products in similar terms: products without the amounts claimed, with wrong ingredients, without active ingredients, or deliberately mislabelled or in fake packaging.

What are the red flags in how a pen is sold?

The US FDA lists warning signs for people getting GLP-1 medicines online. Watch for a seller that:

• offers deep discounts or prices that seem too good to be true;
• sends medicine that looks different from what you received before, or arrives broken, damaged or without instructions;
• does not require a screening and prescription by a licensed doctor;
• has no licensed doctor available to answer questions after delivery;
• makes spelling errors on the label or gives incorrect pharmacy addresses;
• puts a pharmacy name on the label that you think may be fraudulent.

The US FDA also recommends not using any injectable GLP-1 medicine that arrives warm or without enough refrigeration, because this can affect its quality. Our guide to storing GLP-1 pens covers what the labels say about temperature.

In the UK, the MHRA said fake Saxenda pens had been obtained by the public through routes that do not require a prescription. It advised the public not to use any pre-filled weight-loss pens bought online.

FDA Philippines has also warned that medicines bought online may be unregistered, may not be genuine even if they look the same, and may not have been stored correctly (Advisory No. 2021-2381).

What about unapproved products sold as vials or "research" products?

This is a separate problem from fake brand-name pens. The FDA Philippines advisories below name vials and powders for injection. Regulators describe them as unapproved (US) or unregistered (Philippines).

• US FDA. It has warned companies that illegally sold unapproved drugs containing semaglutide, tirzepatide, retatrutide, survodutide or mazdutide "falsely labeled 'for research purposes' or 'not for human consumption.'" It urges consumers not to purchase these products, "which are of unknown quality and may be harmful to their health."
• US FDA, product labels. The US FDA says it is aware of fraudulent products sold as compounded semaglutide and tirzepatide whose labels name pharmacies that do not exist, or name a real licensed pharmacy that did not make the product. This is a US finding about unapproved products.
• FDA Philippines. In 2026 it issued advisories against unregistered tirzepatide products, including one labelled "For research only" (Advisory No. 2026-1309, 17 September 2026) and another sold as a powder for injection with bacteriostatic water (Advisory No. 2026-1283, 16 September 2026). It also warned against two unregistered retatrutide products (Advisories No. 2026-1265 and 2026-1392).

For products like these, FDA Philippines says "the public has no assurance as to its quality, safety and efficacy." Our guide on whether peptides are legal in the Philippines covers the law.

How do you check a GLP-1 product in the Philippines?

Check the product and the seller on the FDA Philippines Verification Portal, and buy only from FDA-licensed outlets.

• Check the product. FDA Philippines tells the public to "always check if the products are registered" on the Verification Portal at verification.fda.gov.ph, or on its list of verified unregistered health products.
• Check the seller. FDA Philippines says the portal can also verify FDA-licensed establishments.
• Buy from licensed outlets. FDA Philippines reminds consumers "to purchase drug products only from FDA-licensed establishments." Under RA 10918, no pharmaceutical product may be dispensed or sold to the public except through a retail drug outlet licensed by FDA Philippines.
• Use a prescription. Under RA 10918, prescription medicines may be dispensed only by a licensed pharmacist and only with a valid prescription.

FDA Philippines says the portal's information is for verification only and is not regulatory advice (Advisory No. 2023-2238). In Advisory No. 2026-0106 it advised the public to rely solely on the portal when confirming a product's status.

No FDA Philippines guidance on how to physically inspect a GLP-1 pen was found. The pen and pack signs above come from WHO, the US FDA and EMA, based on products in other markets. For brand registration here, see our guides to Ozempic in the Philippines and Mounjaro in the Philippines.

What should you do if you suspect a fake?

Stop using it, get medical advice if you have used it, and report it to FDA Philippines.

1. Do not use the pen. WHO advises not using affected products, and EMA says not to use pens you suspect are falsified.
2. Get medical advice if you already used it. WHO advises anyone who has used an affected product, or had an unexpected reaction or side effect, to seek immediate medical advice from a healthcare professional.
3. Report the product to FDA Philippines. Email ereport@fda.gov.ph or use e-Sumbong on www.fda.gov.ph to report suspected counterfeit or unregistered products and unlicensed sellers.
4. Report any side effects. FDA Philippines asks the public to report suspected adverse drug reactions immediately through its online form (https://bit.ly/PHFDAReportSideEffects). General questions go to info@fda.gov.ph.

Selling or importing counterfeit drugs violates RA 9711, the FDA Act of 2009, and RA 8203, the Special Law on Counterfeit Drugs, according to FDA Philippines.

For context, channels in other markets:

These channels are for patients in those markets. In the Philippines, use the FDA Philippines channels above.

What is not known about fake pens in the Philippines?

Quite a lot, based on the sources available for this page.

• No FDA Philippines counterfeit advisory was found. Searches of fda.gov.ph for "ozempic", "mounjaro" and "semaglutide" on 7 October 2026 found no advisory on counterfeit Ozempic, Wegovy, Mounjaro or semaglutide. A search for "semaglutide" returned only an advisory on VAT-exempt health products. This is a search result on that date, not proof that no fakes exist here.
• Registration was checked, packs were not. An FDA Philippines Verification Portal search on 7 October 2026 lists Ozempic, Wegovy and Mounjaro, including Mounjaro KwikPen, as registered prescription drugs.
• No Philippine pack details. The identifiers and pen features above come from packs found in the US, the UK, the EU and Brazil.
• No later WHO alert was searched. The WHO details are as of June 2024.