First Look at How Tirzepatide Affects the Brain's Reward Center — and an Unexpected Finding About Food Cravings | Research

The takeaway

Direct brain recordings from a patient on tirzepatide revealed that increased food preoccupation episodes were preceded by heightened slow-wave activity in the nucleus accumbens, a key reward center.

First-in-human
This is the first time researchers have directly recorded electrical activity from the human nucleus accumbens during incretin-based therapy, revealing unexpected reward-circuit modulation on tirzepatide.

What the researchers found

In a first-in-human investigation, researchers recorded electrical activity directly from the nucleus accumbens — a key brain reward center — of a patient taking tirzepatide (a dual GIP/GLP-1 receptor agonist used for obesity). After starting tirzepatide, the patient experienced increased episodes of severe food preoccupation. These episodes were preceded by a surge in slow-wave (delta-theta, ≤7 Hz) brain activity in the nucleus accumbens, suggesting that the drug modulates reward circuitry in ways that may paradoxically intensify food-related thoughts in some individuals.

Why it matters

GLP-1-based drugs like tirzepatide are widely prescribed for obesity and are known to reduce appetite and food intake. However, their effects on the brain's reward system are poorly understood because directly recording from deep brain structures in living humans is exceptionally rare. This case provides the first direct electrophysiological evidence of how an incretin therapy engages the mesolimbic reward pathway, and the unexpected finding of increased food preoccupation challenges simple assumptions about how these drugs work in the brain.

The numbers in context

n=1, delta-theta frequency ≤7 Hz power increase in nucleus accumbens preceding food preoccupation episodes

How the study worked

Researchers recorded electrophysiology directly from electrodes implanted in the nucleus accumbens of a single patient-participant with obesity who was prescribed tirzepatide. They monitored brain activity patterns before, during, and after episodes of food preoccupation, identifying characteristic changes in delta-theta frequency power that preceded these episodes.

Who was studied

A single patient with obesity who had electrodes implanted in the nucleus accumbens, treated with a short-term course of tirzepatide

What this study cannot tell us

This is a single-patient case report, so the findings cannot be generalized to the broader population taking tirzepatide or other incretin-based therapies. The patient already had electrodes implanted in the nucleus accumbens (likely for another clinical indication), making them a highly atypical case. The short-term course of tirzepatide may not reflect long-term brain adaptations. Causal relationships cannot be established from observational data in one individual.

How to read the evidence

This is a single-patient case report. While the data is unprecedented and published in a top-tier journal (Nature Medicine), findings from one individual with implanted brain electrodes cannot be generalized. It is hypothesis-generating rather than conclusive.

When this study was published

Published in 2025 in Nature Medicine, this is a cutting-edge study at the frontier of understanding how GLP-1-based drugs affect the human brain. The findings are preliminary but highly relevant given the explosive growth of these medications.

The bigger picture

GLP-1-based obesity drugs are among the most prescribed medications worldwide, yet how they affect the brain remains largely a black box. Most evidence comes from animal studies or human brain imaging, which lack the precision of direct electrophysiology. This pioneering case opens a window into the real-time neural dynamics of incretin therapy in the human reward system — and the unexpected finding of increased food preoccupation raises important questions about potential psychological side effects that may affect a subset of patients.

Questions still open

Do other patients on tirzepatide or similar GLP-1 drugs experience similar breakthrough food preoccupation, and is this a common but underreported side effect?
Does the delta-theta power increase in the nucleus accumbens normalize with longer-term tirzepatide use as the brain adapts?
Could monitoring reward-circuit brain activity help predict which patients will respond well versus poorly to incretin-based obesity therapies?

Common questions

Does tirzepatide cause food cravings?

In this single case, a patient on tirzepatide experienced increased episodes of severe food preoccupation, which is unexpected since the drug typically reduces appetite. This doesn't mean it's a common effect — it's one patient, and most people on tirzepatide report decreased appetite and food intake.

What is the nucleus accumbens and why does it matter here?

The nucleus accumbens is a small brain structure at the center of the reward system — it helps drive motivation and pleasure-seeking behaviors, including eating. By recording directly from this area, researchers could see how tirzepatide changed the brain's reward signals in real time, something never done before in a human on this type of drug.

Read the original research

Brain activity associated with breakthrough food preoccupation in an individual on tirzepatide.

Nature medicine, 31(12), 4038-4043

View on PubMed ↗Publisher’s paper ↗

Citation

Choi, Wonkyung; Nho, Young-Hoon; Qiu, Liming; Chang, Andrew; Campos, Gustavo; Seilheimer, Robert L; Wilent, W Bryan; Bakalov, David; Firdous, Nida; Kerr, Marie; Joshi, Disha; Maze, Gabriella; Topalovic, Uros; Batista, Daniel; Suthana, Nanthia; Amaro, Anastassia; Hayes, Matthew R; Cajigas, Iahn; Cristancho, Mario; Allison, Kelly C; Pesaran, Bijan; Scangos, Katherine W; Gold, Joshua I; Wadden, Thomas A; Halpern, Casey H. (2025). Brain activity associated with breakthrough food preoccupation in an individual on tirzepatide.. Nature medicine, 31(12), 4038-4043. https://doi.org/10.1038/s41591-025-04035-5