Semaglutide is a medication used for managing blood sugar levels in adults with type 2 diabetes and for long-term weight management. It is available under brand names like Ozempic, Rybelsus, and Wegovy. Metabolism refers to the complex processes by which the body converts food and drinks into energy to sustain life and all bodily functions.
The Basics of Metabolism
This energy powers various bodily functions, including breathing, blood circulation, cell growth, and nerve function, even at rest. A significant portion of daily energy use, typically 50% to 80%, is accounted for by the basal metabolic rate (BMR). BMR represents the minimum calories required for these basic functions while the body is at rest.
Total daily energy expenditure (TDEE) includes BMR, the energy used for physical activity, and the thermic effect of food, which is the energy spent digesting and absorbing nutrients. Factors influencing an individual’s metabolic rate include body size, body composition (especially muscle mass), age, and activity level. For instance, individuals with more muscle tissue generally have a higher BMR because muscle requires more energy to maintain than fat. Metabolism tends to slow with age, partly due to a decrease in muscle tissue.
How Semaglutide Works
Semaglutide functions as a glucagon-like peptide-1 (GLP-1) receptor agonist, mimicking the natural GLP-1 hormone produced in the gut that regulates appetite and blood sugar levels. It primarily impacts energy intake and glucose regulation through several mechanisms.
It interacts with GLP-1 receptors in the brain, reducing feelings of hunger and promoting a sense of fullness. The medication also slows down gastric emptying, meaning food remains in the stomach longer. This delayed digestion contributes to a prolonged feeling of satiety. Additionally, semaglutide stimulates insulin release from the pancreas in a glucose-dependent manner, meaning it increases insulin only when blood sugar levels are elevated. It also suppresses glucagon, a hormone that raises blood sugar, thereby helping to maintain stable glucose levels.
Semaglutide’s Impact on Metabolic Rate
Semaglutide does not directly increase a person’s basal metabolic rate or energy expenditure. Its effectiveness in weight reduction is primarily due to a significant decrease in caloric intake. Studies have shown that resting metabolic rate, when adjusted for lean body mass, does not differ between semaglutide treatment and placebo.
Weight loss itself can lead to a reduction in BMR because there is less body mass for the body to maintain. Therefore, while semaglutide promotes weight loss, this weight loss might, in turn, lead to a lower BMR. The medication’s direct action is not to accelerate the metabolic rate; observed changes are a consequence of reduced calorie consumption.
Broader Metabolic and Health Effects
While semaglutide does not directly speed up metabolism, it offers various benefits for overall metabolic health beyond weight loss. It improves insulin sensitivity, allowing the body to use glucose more efficiently and stabilizing blood sugar fluctuations, which benefits individuals with type 2 diabetes. Semaglutide has also been linked to a reduction in systemic inflammation.
The medication contributes to improved cardiovascular health by lowering blood pressure and enhancing lipid profiles. Studies show it can significantly decrease systolic blood pressure, especially in individuals with obesity and hypertension. It can also lead to healthier lipid levels, including a reduction in LDL cholesterol and triglycerides.