In adults with obesity and prediabetes, losing weight through calorie reduction maintains muscle mass, but taking 1.8 mg of liraglutide daily causes muscle mass to decrease.
Mechanism
Synthesis from 1 study
The drug tricks the body into feeling full, but also tells it to break down muscle for energy when calories are low. Eating fewer calories without the drug keeps the body from breaking down muscle because it still has the signals needed to protect it.
Most probable mechanism
When a hormone-like drug activates receptors in the brain that signal fullness, the body starts breaking down muscle for energy instead of preserving it, even when calorie intake drops. This happens because the drug changes how the body decides which tissues to burn, favoring muscle over fat.
Liraglutide binds to glucagon-like peptide-1 receptors on hypothalamic glutamatergic neurons, enhancing satiety signaling and reducing appetite drive
Sustained GLP-1 receptor activation increases hepatic glucose production and reduces insulin sensitivity, elevating circulating glucagon and cortisol levels
Elevated glucagon and cortisol promote proteolysis in skeletal muscle by upregulating ubiquitin-proteasome and autophagy-lysosome pathways
During negative energy balance, the metabolic priority shifts from preserving lean mass to mobilizing amino acids for gluconeogenesis and energy production
Reduced insulin signaling and increased catabolic hormone activity suppress muscle protein synthesis and accelerate lean tissue loss
Evidence from Studies
Supporting (1)
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Contradicting (0)
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