Semaglutide Doesn't Rewire the Brain's Appetite-Suppressing Neurons, Study Finds

Semaglutide and lipidized prolactin-releasing peptide (LiPR) — two anti-obesity compounds — did not change the proportion of POMC-expressing neurons when applied to human stem cell-derived hypothalamic neurons or mouse brain tissue. LiPR also did not alter POMC neuron shape, gene expression patterns, or the generation of new POMC neurons in mice. This suggests anti-obesity medications do not work by rewiring the brain's appetite-suppressing neuron population.

Researchers grew hypothalamic neurons from human induced pluripotent stem cells (iPSCs) in the lab and exposed them to semaglutide or LiPR during their maturation phase. They then measured the proportion of POMC-expressing neurons. In a separate experiment, they administered LiPR to live mice and examined newly generated POMC neurons in the medial basal hypothalamus.

Scientists have wondered whether weight-loss drugs like semaglutide might permanently reshape the brain's appetite circuits by changing which neurons mature into appetite-suppressing cells. This study suggests they don't — the drugs appear to work through other mechanisms rather than by altering the fundamental composition of hypothalamic neurons. This is reassuring because it means the drug effects are likely reversible rather than structural.

As millions of people take GLP-1 drugs for weight loss, a key question is whether these medications cause permanent changes to brain circuitry. This study provides early evidence that semaglutide does not fundamentally alter the brain's appetite neuron population — suggesting the appetite effects may be pharmacological rather than structural, which could explain why appetite often returns after stopping the medication.

This study used iPSC-derived neurons in a dish, which may not fully replicate how neurons behave in a living human brain. The mouse experiments only tested LiPR, not semaglutide. The study examined only POMC neurons and did not assess other neuron types that might be affected. Treatment duration and dosing in the lab setting may not reflect long-term clinical use.