The new medications for the treatment of overweight and obesity-related complications are molecules already used for the treatment of type 2 diabetes (liraglutide, semaglutide, tirzepatide). In Italy, only liraglutide can currently be used for the treatment of excess weight, but in the near future (either just before or just after summer) two other molecules, already in use in the USA and some European countries (semaglutide, tirzepatide), should become available. In recent months, news about these medications has appeared multiple times in both general and scientific media, and the highly authoritative journal Science has called these drugs “the discovery of 2023.” But where do we truly stand in understanding this new therapy? Let me address the most interesting points.

1. How do they work? They reduce hunger and provide early satiety, leading people to eat less spontaneously, without the effort of dieting. It should be considered that about 10% of patients have to stop the treatment due to side effects (see below), and another 10% do not respond to the treatment.
2. How much weight can be lost? The expected weight loss varies depending on the molecules. Liraglutide, the oldest molecule and perhaps for this reason the least interesting, can provide a loss of about 8-10% of total body weight: if I weigh 100 kg, I can expect to lose about 10 kg on average. Semaglutide can lead to a 15% loss, and tirzepatide offers slightly more. In comparison with bariatric surgery, it should be considered that the weight loss from surgery is about 30% of total body weight, perhaps slightly more. However, other molecules that seem to offer greater weight loss than the current drugs are under study.
3. What are the side effects? The most common are nausea and constipation. Less frequent but possible side effects include vomiting, gastroesophageal reflux, diarrhea, headache, and fatigue. Significant weight loss can lead to gallstones, and thus potential (rare) cholecystitis and pancreatitis. A lot has been said in the past about the risk of thyroid cancer and increased suicide risk. The first risk (thyroid cancer) has been completely ruled out by EMA (European Medicines Agency) and AIFA (Italian Medicines Agency), while regarding the second (suicide risk), a recent study involving nearly two million patients has excluded an increased suicide risk in patients treated with semaglutide.
4. Do they replace surgery? For now, absolutely not. Given the expected weight loss, it is clear that for a person weighing 85 kg, losing 8-10 kg can be very beneficial, while for a person weighing 130 kg, losing 13-15 kg may improve blood tests but will not be enough to consider the patient free from the obesity problem. These medications can, however, be a very useful tool either to help lose weight before surgery or to help someone who has been operated on, has gained back some weight after a few years, and doesn’t want to risk needing a second surgery in the future.
5. Are they covered by the national health system? Unfortunately, no. Only for people with type 2 diabetes can these medications be prescribed within a therapeutic plan, and therefore covered by the national health system. For people with complicated overweight or obesity, the medication is at the patient’s expense, and the price is high. Semaglutide is not yet on sale in Italy, but it will be soon. The final price is unknown, but in the USA, a one-month therapy costs about 1,200 dollars, while in Switzerland, it ranges from 500 to 600 euros. It is hoped that the price in Italy will be lower, but by how much, it is impossible to predict.