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Mechanisms of injectable medications for weightloss
In recent years, the use of weight-loss injections (also known as slimming injections or injectable pharmacological treatment for obesity) has become a central topic in both medicine and public discussion.
These are relatively new medications for weight management that offer an additional option for people living with overweight or obesity. When combined with proper nutrition and physical activity, these treatments can help reduce hunger, support eating less, and lead to meaningful weight loss.
The most commonly used medications today belong to a family called GLP-1, named after a natural hormone involved in regulating hunger and satiety. This hormone is released in the intestine after eating and “communicates” with different systems in the body. It affects satiety centers in the brain, slows stomach emptying, and also influences blood sugar balance.
Modern injections essentially mimic the activity of this natural hormone. They are called GLP-1 analogs - medications that imitate the hormone’s action but remain in the body longer. As a result, they allow a natural reduction in daily calorie intake, since patients experience less hunger and prolonged fullness after meals.
In recent years, several key medications for obesity treatment have entered the market. Some act through the GLP-1 mechanism alone, while others combine additional mechanisms. The main medications include:
A medication based on the active ingredient semaglutide. It is given as a once-weekly subcutaneous injection and is specifically indicated for obesity treatment. Wegovy acts on satiety centers in the brain, reduces hunger, and slows stomach emptying.
A newer medication that works through a dual mechanism: both GLP-1 and another hormone called GIP. This combination affects appetite regulation, fat metabolism, and blood sugar balance. Studies show that the medication can lead to significant weight loss.
An older medication from the same family that also works via the GLP-1 mechanism. Unlike Wegovy and Mounjaro, it is administered as a daily injection.
It is important to note that other medications with a similar mechanism also exist, but they are primarily intended for treating type 2 diabetes and are not defined as first-line obesity treatments for people without diabetes.
One of the reasons weight-loss injections have become a major focus in medicine is their unique mechanism of action. Unlike diets or supplements that attempt to influence appetite indirectly, these medications act on a natural hormonal system responsible for regulating hunger and satiety.
Wegovy, for example, is based on mimicking a natural hormone called GLP-1. This hormone is released in the intestine after eating and helps the body understand that it is time to stop eating. When using the medication, this hormonal effect is enhanced, creating a feeling of fullness earlier during the meal.
GLP-1 is part of a complex communication system between the digestive system and the brain. After eating, it is released from the intestine and travels through the bloodstream to brain areas responsible for appetite regulation.
When this signal reaches the brain, it activates mechanisms that reduce hunger and increase satiety. In simple terms, the body receives the message that enough food has been consumed.
Modern medications do not create a new hormone but mimic the action of the natural one. The difference is that the medication remains in the body longer, allowing it to influence appetite over time.
The medication’s effect does not occur only in the brain. A key part of the mechanism takes place in the digestive system.
One of GLP-1’s main effects is slowing stomach emptying. When the stomach empties more slowly, the feeling of fullness lasts longer after eating.
The result is a combination of two effects:
When these two effects work together, many people naturally eat less during the day, without feeling that they are “fighting” hunger as in traditional diets.
GLP-1 also plays an important role in regulating blood sugar. It increases insulin secretion and reduces glucagon secretion, helping maintain better blood sugar balance after meals.
This effect is one reason medications in this family were originally developed for type 2 diabetes. Later, it was discovered that they also affect body weight, leading to the development of versions specifically for weight management.
When hunger decreases and satiety appears earlier, a natural shift in eating habits may occur.
Many people report that they:
This change does not come from external restriction, but from a shift in the body’s hunger and satiety signals.
Ultimately, weight loss occurs when the body consumes fewer calories than it burns. When the medication reduces hunger and increases satiety, many people naturally decrease their daily food intake.
Over time, this reduction in calorie consumption can lead to meaningful weight loss. However, it is important to remember that the medication does not work alone. Combining it with balanced nutrition and physical activity can help achieve better results and maintain them over time.
Leumit’s dietitians are available to support you throughout your weight-loss journey, in clinics or via phone consultations. They can help you navigate the process, build a personalized plan, manage side effects, and develop habits that support long-term success.
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