Unregistered products

What tests found

Lab tests of products sold online found from about half to almost double the amount on the label: 51%, 190% and 165% in three vials sold as retatrutide. Three 'research use only' semaglutide vials had 28.6% to 38.7% more than the label, purity far below the advertised figure, and bacterial toxins in all three.

The FDA reports dosing errors with compounded semaglutide of 5 to 20 times the intended dose, some ending in hospital stays. By May 31, 2026, it had received 990 adverse event reports for compounded semaglutide and more than 730 for compounded tirzepatide, and it notes that many go unreported.

Falsified pens have been found in Brazil, the UK and the US, and the WHO warned that a pen may contain a different medicine, such as insulin. In Mexico, a cartridge labeled tirzepatide turned out to contain semaglutide and bacterial growth.

What regulators say

Regulators in several countries have warned about these products, and the WHO has issued an alert about falsified pens. Your country's medicines regulator lists the products it has flagged.

Signs worth knowing

• Today

  Redness, warmth, swelling or pain at the injection spot that spreads, or pus

  With fever, chills or feeling unwell overall, it moves to Now.

• Today

  A much stronger effect after a new vial or a new preparation: vomiting that won't stop, not keeping fluids down

  Fainting moves it to Now.

• Now

  If you get shaky and break into a cold sweat, or feel confused, after a dose, call emergency services now.

  A falsified pen may contain insulin.

• Now

  Yellow skin or eyes, or dark urine

  Cases of liver injury were reported in Australia with a product sold as retatrutide.

• Soon

  No effect, or hunger rising, with a new vial

  The product may not be what the label says. Don't make up for it on your own.

• Soon

  A product that arrived warm, or with mismatched batch numbers or label errors

  Show it to a pharmacist or doctor before using it.

Telling your doctor

'Research use only' on a label doesn't make a product safe for people, and a high purity figure on a lab report doesn't tell you how much medicine is in the vial. If the effect changed suddenly after a new vial or batch, that's a signal, not an overreaction.

For today: in your profile you can record where your medicine comes from; by default it stays on your phone. Take that record, the product and its label to your doctor or pharmacist.

To take to your appointment

• My medicine doesn't come from a pharmacy with a prescription. What should we watch?
• The effect changed after a new vial. What should I do?