Since June 15, 2026, two anti-obesity injections are reimbursed in France under strict conditions. Wegovy (semaglutide) and Mounjaro (tirzepatide) join Saxenda (liraglutide) in the injectable therapeutic arsenal, but their prescription remains regulated as a second-line treatment, after the failure of nutritional management. The market for slimming injections attracts attention well beyond the medical framework, raising questions about their real effectiveness and limitations.
Weight regain after stopping treatment: the blind spot of slimming injections
The mechanisms of action of these molecules are well documented. However, the question of what happens when treatment is stopped deserves more attention. According to data reported by France Info in January 2026, stopping treatment leads to rapid weight regain. This data changes the interpretation of the effectiveness claimed by these treatments.
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Incretin mimetics (semaglutide, tirzepatide, liraglutide) act on appetite and gastric emptying as long as they are administered. Once interrupted, hunger signals regain their initial intensity. Therefore, the weight loss achieved during treatment is not permanently secured without a maintenance strategy.
This observation raises a question about the optimal duration of treatment. Current protocols include a dose escalation phase, followed by a maintenance phase, and then a gradual cessation to stabilize weight. Field reports vary regarding patients’ actual ability to maintain their results once the pen is put away. Choosing a slimming injection for weight loss thus requires integrating this temporal dimension from the outset.
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Semaglutide or tirzepatide: which molecule produces the best weight loss results
Wegovy is based on high-dose semaglutide. It targets a single receptor, GLP-1, a satiety hormone naturally produced by the intestine. Mounjaro uses a dual mechanism of GLP-1 and GIP, giving it a broader action on appetite regulation and carbohydrate metabolism.
Available summary data indicate that modern incretin mimetics can produce a weight loss of about 10 to 25% of initial weight depending on the molecule, dose, and severity of obesity. Several sources from 2026 present tirzepatide as superior to semaglutide in terms of the magnitude of weight loss.
However, individual effectiveness varies significantly. The patient’s metabolic profile, eating habits, and level of physical activity modulate the results. A treatment that works remarkably well for one person may prove disappointing for another, without the molecule being at fault.
And Saxenda in all this
Saxenda (liraglutide) remains available but is positioned as a secondary option. Its effectiveness is described as lower than that of semaglutide and tirzepatide. It also requires a daily injection, compared to a weekly injection for Wegovy and Mounjaro. This more demanding administration schedule, combined with lesser results, explains why prescriptions are now leaning towards the two newer molecules.
Prescription and reimbursement conditions in France: a very restricted framework
The reimbursement of Wegovy and Mounjaro since June 15, 2026, does not apply to all overweight patients. Only cases of severe or massive obesity are eligible, and under strict conditions. Here are the main criteria that govern access to these treatments:
- The treatment is administered as a second-line option, after documented failure of nutritional and behavioral management for at least six months
- The first prescription must be made by a specialist doctor (endocrinologist, hospital nutritionist), with general practitioners excluded from the initial prescription
- Regular medical follow-up is required before and during treatment to monitor tolerance and adjust doses
This restriction has a direct consequence: nearly one million patients could be eligible for reimbursement, but a large portion of those wishing to use these injections to lose a few pounds before summer do not fall within this framework. On France Info, Sébastien Czernichow emphasized that these medications “are not meant for aesthetics.”
Side effects of GLP-1 injections: what prescribers monitor
The most common side effects are digestive: nausea, vomiting, diarrhea, constipation. They mainly occur during the dose escalation phase and tend to diminish over time. The strategy of gradually increasing doses aims specifically to limit these disturbances.
More recent signals deserve attention. According to Top Santé, a new suspicion of side effects has been reported by doctors regarding slimming injections. The available data do not yet allow for conclusions about the severity or frequency of this signal, but it illustrates that pharmacovigilance remains active regarding these relatively new molecules.
Another point of vigilance: the parallel market. “Fake injectors,” fraudulent practitioners offering injections outside the medical framework, have been reported. Resorting to these channels exposes individuals to uncontrolled products, inappropriate dosages, and a complete lack of follow-up.
Orlistat: an oral alternative with modest results
Orlistat (Xenical) remains authorized in France in tablet form. Its mechanism is entirely different: it blocks the absorption of some dietary fats. Its effectiveness is described as modest compared to modern incretin mimetics. It may be suitable for profiles for which injection is not indicated, but the digestive effects (oily stools, urgent bowel movements) limit its acceptability in daily life.
The landscape of anti-obesity treatments is evolving rapidly. New molecules are being developed at Novo Nordisk and Eli Lilly, the two laboratories that dominate this market. The question is no longer just which injection leads to the most weight loss, but how to maintain this loss over time, and at what cost to the healthcare system.