Unregistered tirzepatide: how to know what you are being injected with

Before you use any tirzepatide or semaglutide, ask for its registro sanitario number and look it up yourself in Invima’s registration search, by product name, registration number or active ingredient [10][12]. Invima (Instituto Nacional de Vigilancia de Medicamentos y Alimentos) is Colombia’s national drug and food regulator, and the registro sanitario is the marketing authorization number it grants. A product without that registration has not been evaluated for quality, safety or efficacy, and nobody knows what it contains, how it was made, or how it was stored and shipped [10]. That is the first check I would do, and below are the other six.

I am telling you this as an aesthetic physician in Barranquilla, Colombia, who works with facial treatments and with weight management. I think these medicines are good news. I care more about what you are being injected with than about the place where you are treated. And not every product without the original brand is fake: the question is whether it is registered, and whether someone is selling you one thing while telling you it is another.

If you live outside Colombia, the same idea applies: check the product with your own country’s medicines regulator, such as the FDA in the United States, or the EMA or your national medicines agency in Europe.

If they tell you “it’s the same as Mounjaro”, that phrase is in the FDA’s warnings

Tirzepatide is approved by the FDA, the US drug agency, under two brand names: Mounjaro, for type 2 diabetes, and Zepbound, for chronic weight management [2]. Semaglutide has its own, Ozempic and Wegovy [3][4]. Unapproved versions, including compounded preparations, do not go through the FDA’s review of safety, effectiveness and quality [1]. And among the warning signs the FDA itself teaches consumers is being assured that a compounded product is the same as the approved one [1]. In other words, the very phrase used to sell it to you is a signal to stop.

“It comes from the United States” does not guarantee anything either. The FDA has documented counterfeit Ozempic inside its own country, and fraudulent semaglutide and tirzepatide carrying labels from pharmacies that do not exist or that never prepared that product [1]. In 2024 the WHO confirmed falsified batches of Ozempic in Brazil, the United Kingdom and the United States, which had entered the regulated supply chain [5]. The European Medicines Agency reported fake pens with batch numbers, barcodes and serial numbers copied from genuine packaging [8]. That is why a box that looks fine does not replace checking the registration.

Invima has already warned about unregistered tirzepatide sold on social media for aesthetic use

In April 2026 Invima issued an alert about an injectable tirzepatide without marketing authorization that was being offered on social media for aesthetic use [10]. In that alert it reminds the public that tirzepatide is a medicine, not an aesthetic product, that it is used only with a medical prescription and according to the indications approved in Colombia, and that adverse reactions such as acute pancreatitis have been reported with its improper use [10]. In September 2025 it had already warned about a product sold as tirzepatide with vitamin B12, also unregistered [11], and in July 2024 about falsified batches of Ozempic in Colombia and other countries [9]. If someone offers you something similar, you can look up the health alerts on Invima’s website before you buy.

Inside a falsified vial there may be no active ingredient, a different amount from the one on the label, another undeclared substance such as insulin, or contamination from being made in a non-sterile place, according to the WHO [6]. None of that is visible to the naked eye. The FDA has also received reports of adverse events with compounded versions of semaglutide and tirzepatide, some due to dosing errors, and warns that it probably receives fewer reports than the cases that occur [1].

Registered and prescribed, it is still a medicine, with side effects and contraindications

A registered medicine, prescribed by a doctor who evaluated you, bought at a pharmacy and with follow-up, is a tool. In December 2025 the WHO published its first guideline on these medicines for treating obesity: it gives them a conditional recommendation in adults, except during pregnancy, within a plan that includes diet, physical activity and support from health professionals [7]. The same guideline warns that demand has driven up falsified and substandard products, and that quality depends on regulated distribution and on prescription by a qualified professional [7].

According to the FDA, tirzepatide acts on receptors for hormones produced by the gut to reduce appetite and food intake [2]. It is a facilitator, let’s put it that way: it does not do the work for you, it makes it easier. The FDA-approved labels list nausea, diarrhea, vomiting, constipation and abdominal pain among the common side effects, and state that these medicines should not be used if you have a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 [2][3][4]. Those questions get asked at the consultation, before the first dose. A vial that arrives by courier does not ask them.

If you are already using it, do this this week

Look up the registration of the product you have in Invima’s search [12]. If it does not show up, or if you bought it outside an authorized pharmacy, book a consultation and bring the box, the receipt and the prescription if you have it. If you noticed anything unusual after injecting it, talk to a health professional so it gets reported [5][6]. That visit may end with you continuing, switching or using nothing at all, and any of the three is fine.