Next-Generation Weight Loss: Tirzepatide and Retatrutide vs Semaglutide in 2026
Tirzepatide (Mounjaro) and the emerging retatrutide are showing unprecedented weight loss results — up to 24% body weight reduction. This guide compares all GLP-1 class drugs and what European patients need to know.
The GLP-1 Revolution: From Ozempic to Triple Agonists
The weight-loss pharmacology landscape has transformed dramatically since 2021. First came semaglutide — delivering 15–17% weight loss. Then tirzepatide — a dual GLP-1/GIP agonist — achieved 20–22% in the SURMOUNT trials. Now retatrutide — a triple GLP-1/GIP/glucagon agonist — has shown 24.2% weight reduction at 48 weeks in Phase 2 trials. For context: bariatric surgery achieves 25–30%. We are approaching surgical-level weight loss in an injectable medication.
Tirzepatide (Mounjaro): Dual Agonist
Tirzepatide activates both GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptors. GIP activation appears to enhance GLP-1 efficacy through synergistic effects on satiety, metabolism, and fat tissue. SURMOUNT-1 results: 22.5% weight reduction at 72 weeks on 15 mg/week. Doses: 2.5 mg escalating to 5, 7.5, 10, 12.5, and 15 mg. Available in the EU as Mounjaro (EMA-approved for T2D, increasingly used off-label for obesity). Side effect profile similar to semaglutide but with higher rate of nausea at dose escalation.
Semaglutide 2.4 mg (Wegovy): The Current Standard
Wegovy at 2.4 mg weekly remains the gold standard for GLP-1 monotherapy in Europe, with the most robust clinical evidence and longest track record. STEP-1 trial: 14.9% weight loss at 68 weeks. SELECT cardiovascular outcomes trial showed 20% reduction in major cardiovascular events — making it the first weight-loss drug with proven CV benefit. For patients who cannot access tirzepatide, Wegovy at 2.4 mg remains the best-evidenced option.
Practical: Semaglutide or Tirzepatide?
Expected weight loss: Semaglutide ~15%, Tirzepatide ~22%. Tolerability: similar GI side effects; tirzepatide may have higher nausea in early weeks. Cost: Mounjaro typically 20–30% more expensive. Availability: Ozempic shortages have been widespread since 2023; Mounjaro supply is now more stable in Europe. Clinical decision: if weight loss of >20% is the goal and cost is not prohibitive, tirzepatide offers meaningfully superior outcomes. For patients with T2D, both are EMA-approved.
Where to Buy GLP-1 Medications in Europe
PharmaForce stocks Ozempic (semaglutide 0.5–2 mg), Wegovy (semaglutide 0.25–2.4 mg), Mounjaro (tirzepatide 2.5–15 mg), and Saxenda (liraglutide) for delivery across 30+ EU countries. All products are original branded pharmaceuticals from verified EU suppliers. Delivery to Germany, France, Poland, Netherlands, Belgium, Austria, Switzerland, Italy, Spain and all major EU markets in 3–8 business days. Discreet plain packaging. Free shipping on orders over €150.
Written by
Dr. Anna Fischer
Endocrinologist, MD