Scientists at the National Institutes of Health have discovered how weight‑loss medicines such as semaglutide act inside brain cells. Their work with mice shows new details about the signals that make these drugs work differently for each person and why the results can become weaker over time.
Drugs that activate the GLP‑1 receptor, like Ozempic and Wegovy, are already known to cut appetite and help people lose weight. Researchers now know more about which parts of the brain are involved, but they have just begun to see what happens inside the nerve cells they target.
Brain Signals That Lead to Weight Loss
The team blocked or removed certain signaling molecules inside neurons to see which pathways mattered most. They found that semaglutide works best when a molecule called cyclic adenosine monophosphate (cAMP) builds up in a tiny brain area called the area postrema, which helps control hunger. Not every neuron responded the same way, though.
Why the Benefits May Fade
To see if they could make the signal last longer, researchers gave the mice a drug named roflumilast. This medicine stops an enzyme called PDE4 from breaking down cAMP, letting more neurons keep the signal active for a longer period. The result suggests future GLP‑1 treatments might stay effective longer, possibly needing fewer injections and helping people get past weight‑loss plateaus.
What Comes Next
A challenge of the study was that the scientists could only watch the inside of brain cells for a few hours at a time. They hope new tools will let them follow the drug’s effects for days or weeks. Understanding these brain chemistry details could guide the creation of stronger, longer‑lasting weight‑loss medicines.