European Commission authorizes Mounjaro

Tirzepatide, sold as Mounjaro, received a marketing authorization valid throughout the European Union on September 15, 2022 ^[1]. The decision cleared the once-weekly injection for use in the EU's member states and made Europe the second major market, after the United States, to act on Eli Lilly's dual GIP/GLP-1 receptor agonist.

Tirzepatide works differently from semaglutide, the active ingredient in Ozempic, Wegovy and Rybelsus. According to the European Medicines Agency, tirzepatide mimics two gut hormones — glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) — which bind to receptors in organs including the pancreas and brain. That increases the insulin the pancreas releases in response to food, lowers blood glucose, and also reduces appetite ^[1].

What the trial numbers showed

The EU review rested on five main type 2 diabetes studies involving more than 6,000 adults, with the primary measure being change in HbA1c, a blood test that reflects average glucose control ^[1].

In two of those studies, tirzepatide lowered HbA1c by up to 2.1 and 2.6 percentage points at 40 weeks — first when added to lifestyle changes alone, then when added to insulin glargine with or without metformin. Placebo groups saw no decrease and a 0.9-percentage-point decrease, respectively ^[1].

A third study compared tirzepatide directly against semaglutide on top of metformin. Tirzepatide lowered HbA1c by up to 2.5 percentage points at 40 weeks, versus 1.9 percentage points with semaglutide ^[1]. A fourth study found a reduction of up to 2.4 percentage points at 52 weeks on a background of metformin with or without an SGLT2 inhibitor, compared with 1.3 points for insulin degludec. A fifth found up to 2.6 percentage points at 52 weeks when added to as many as three oral medicines, compared with 1.4 points for insulin glargine ^[1].

The EMA's current overview page also describes evidence supporting uses added after the original 2022 authorization. A weight-management study of more than 2,500 adults with obesity (BMI over 30) or who were overweight (BMI 27 to 30) with at least one weight-related health problem found average weight reduction of at least 15% at 72 weeks depending on dose, versus 3% with placebo. More than 85% of participants on tirzepatide lost at least 5% of their weight, compared with 35% on placebo ^[1]. A separate study in 99 adolescents aged 10 to under 18 with type 2 diabetes reported HbA1c reductions of about 2 percentage points at 30 weeks, versus 0.2 with placebo ^[1].

The most common side effects — those affecting more than 1 in 10 people — are low blood glucose when the drug is used with a sulfonylurea or insulin, nausea, vomiting, abdominal pain, constipation and diarrhea ^[1]. European regulators described the gut-related effects as generally mild or moderate, occurring more often shortly after a dose increase, and "manageable" overall ^[1].

Why it matters for patients

For US readers, an EU authorization does not change what is available at an American pharmacy. What it does offer is a second, independent regulatory read of the same underlying evidence. The EMA concluded that tirzepatide lowered glucose "without significantly increasing the patient's risk of having low glucose levels," and that weight loss in the obesity trial was mainly loss of fat mass, alongside improvements in blood pressure and blood fats ^[1].

The head-to-head comparison against semaglutide is the number many patients ask about: 2.5 versus 1.9 percentage points of HbA1c reduction at 40 weeks in one trial on top of metformin ^[1]. That is a single study with specific doses and a specific population, not a guarantee of how any one person will respond, and the source does not break out results by dose level.

It is also worth noting what the source does not say. The EMA overview does not report cardiovascular outcome results, long-term data beyond 72 weeks, pricing, or how quickly individual EU countries made the drug available. Those points are not yet known from this material.

What happens next

The EU authorization dates to September 15, 2022 ^[1]. The EMA first published its plain-language Mounjaro overview on November 25, 2022, and the page has been revised since — its listed last update is August 18, 2026 — with the current version covering both type 2 diabetes in people aged 10 and up and weight management in adults ^[1]. The agency says data on the medicine are continuously monitored and suspected side effects are evaluated on an ongoing basis ^[1].