Hormonal
GLP-1 receptor agonists (GLP-1RAs) such as semaglutide and tirzepatide reduce body weight primarily by suppressing energy intake through activation of GLP-1 receptors in the central nervous system (CNS) and peripheral vagal afferent pathways, rather than by increasing energy expenditure.
GLP-1 medications like semaglutide and tirzepatide are highly effective for weight loss, primarily by reducing appetite and food intake through brain and gut signaling. They are taken once weekly. While they achieve significant weight loss (15-20%+ in trials), real-world results vary, and about a third of users may not lose enough weight to be clinically effective. Common side effects like nausea are frequent but often manageable with dose titration. These drugs are not a magic bullet for everyone, especially those with type 2 diabetes or lower starting weights, and require medical supervision.
Notably, these drugs reduce weight primarily by reducing energy intake, via activation of the GLP-1 receptor on multiple sites of action primarily in the central nervous system... endogenous gut-derived GLP-1 plays a role in satiation in rodents and humans... acting peripherally as an interoceptive input to central eating control networks
Why this rating
Based on a synthesis of multiple clinical trials (STEP, SURMOUNT, SELECT) and mechanistic studies cited in a 2025 review.
Source
GLP-1 and the Neurobiology of Eating Control: Recent Advances
Lauren A. Jones et al. · Endocrinology · 2025
DOI 10.1210/endocr/bqae167
Related findings · Hormonal
- Initial treatment for type 2 diabetes should be a combination of metformin and either an SGLT-2 inhibitor or a GLP-1 receptor agonist to achieve cardiorenal protection, rather than monotherapy or older agents like sulfonylureas.Strong
- For patients with specific monogenic obesity syndromes (leptin deficiency, POMC/PCSK1/LEPR mutations), targeted pharmacotherapy (recombinant leptin or setmelanotide) is highly effective and should be prioritized, unlike in polygenic obesity.Strong
- Continued weekly administration of 2.4 mg subcutaneous semaglutide prevents weight regain and promotes further weight loss in adults with overweight or obesity, whereas switching to placebo results in significant weight regain.Strong
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