Doctors say Ozempic alters your brain chemistry in this surprising way
By now, you probably know that Ozempic can have a big impact on your body. But what might be news to you is that it also leads to major brain changes.
Ozempic and other related weight loss medications interact between your body and your brain to help you stay feeling full and have fewer cravings, aiding in weight loss (and leading to anywhere from 5 to 20% of reduced weight in a year).
The success of these drugs reveals a lot more about the role that the brain plays in weight loss in general. There’s still a lot we don’t know about how and why Ozempic and its fellow glucagon-like peptide-1 agonist meds (commonly referred to as GLP-1s) impact the brain—but we do know that they mimic a naturally occurring hormone in the brain that controls mechanisms like satiety and appetite, among others. And, researchers and doctors are saying its impact can go beyond diabetes and weight loss, treating brain-related diseases from addiction to Alzheimer’s.
Here’s what we know so far about what Ozempic does to your brain.
Meet the experts: Michael Russo, MD, is a board certified bariatric surgeon at MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center. Alexandra Sowa, MD, is an obesity medicine specialist and author of the upcoming book The Ozempic Revolution.
The weight-loss gut-brain connection
What’s unique about GLP-1s—a.k.a. Ozempic, Monjauro, Wegovy, and Zepbound, among others—is that they target hormones, which play a major role in your weight and weight loss, says Dr. Russo. These drugs work by mimicking a hormone that signals satiety, keeping you fuller for longer and requiring you to eat less.
While this hormone is released in your gut, it’s also released in your brain, creating a feedback loop between the two that tells you when you’re full, says Dr. Russo. (This is just one of the interactions that happens along the gut-brain axis, which refers to the different hormones, microbiota, and more that connect both parts of the body, per a 2020 review in Frontiers.)
For people who carry a lot of weight, this feedback loop gets disrupted. This happens through a combination of genetics and environmental factors—like consuming a diet of ultra-processed foods—that dysregulate your hormones and rewire your brain, says Dr. Sowa. These dysregulated hormones contribute to just about—from how easy it is to gain weight, how hard it is to lose, and how and where it’s stored in the body, she says. (This is also why the advice, 'just eat less', isn’t helpful for weight loss, says Dr. Sowa. A lot of times, there’s something more than diet and exercise impacting your size: your brain.)
As a hormonal med, GLP-1s work along this gut-brain axis to get you 'get back to baseline', says Dr. Russo. As for where exactly in your noggin GLP-1s are working, experts think most of the action is in the hypothalamus. This is a 'primitive' part of the brain that drives and encourages compulsions to eat, sleep, and reproduce, says Dr. Russo. 'We think that GLP-1s are likely affecting this pleasure and reward centre—almost the addiction centre—in the brain that can have us act in a compulsive way to seek certain types of pleasurable experiences', says Dr. Russo.
While you may not think food would have anything to do with this addiction centre of the brain, it absolutely can. We know that a Western diet, characterised by processed foods and liquid sugars, is addictive, as confirmed by a 2020 article in Nutrients.
We also know that GLP-1s modulate dopamine, which plays a big role in addiction, per a 2022 review in The British Journal of Pharmacology. So, part of the reason GLP-1s help you lose weight is by curbing cravings and food noise, partly because the hit of dopamine you get from eating 'highly palatable foods' like sweets and snacks isn’t quite as high. While GLP-1s tamper down levels of dopamine that are stimulated from something like alcohol or drugs, they shouldn’t impact the baseline level of dopamine someone has, the review says.
GLP-1s don’t just reduce your appetite overall, says Dr. Sowa. While taking a GLP-1 medication, people also report changing the kinds of foods they want to eat. Processed foods like sweets are typically less appealing, and some foods might even taste differently, says Dr. Russo. Research is still emerging, but one study done in humans found that while in the weight loss phase of taking a GLP-1 (compared to the maintenance phase), patients had a decreased preference for high-fat, savoury foods, according to a 2024 review in the International Journal of Obesity. Another 2023 review in Diabetes, Metabolic Syndrome and Obesity similarly found that people reported a decreased preference for sweet, savoury, and dairy foods while on semaglutide.
What these brain changes mean beyond food noise and weight loss
GLP-1s don’t just have your brain craving less junk food; experts are hopeful that they might be able to treat substance use disorders, as Women’s Health reported previously. Early studies mostly done in mice, as well as limited studies done on humans, are finding the potential to reduce addictive behaviours for people with alcohol, nicotine, and opioid dependencies, according to a September 2024 review in Pharmacological Research.
After analysing data from 228,000 people in Sweden, researchers wrote in a November 2024 study in JAMA Psychiatry that people on a GLP-1 medication had a lower risk of being hospitalised for alcohol-related issues, concluding that they 'offer promise as a novel treatment to reduce alcohol consumption and to prevent development of alcohol-related outcomes'. Again, research on this is developing in real time, so docs aren’t quite sure what’s behind this effect. It’s likely related to the same pathway in the hypothalamus that reduces food cravings and reduces the hit of dopamine you get, says Dr. Russo.
On the flip side of this, a less activated reward centre in the brain could also impact the enjoyment you get from other, healthy activities, like a hobby you really love, Dr. Russo points out. A small number of patients—less than 1% in his practice, he notes—experience something called anhedonia, or lack of interest in things they previously found pleasurable while on a GLP-1.
How GLP-1s might improve brain health
One more exciting thing that GLP-1s might be able to do to your brain? Lower its risk of Alzheimer’s and dementia. If you’re wondering why—you guessed it—researchers are not quite sure yet. In October 2024, a study in Alzheimer’s and Dementia linked semaglutide medications and Alzheimer’s, finding that type-2 diabetes patients taking those meds compared to other treatments had a 'significantly' lower risk of developing the degenerative brain disease.
A potential reason is that GLP-1s have an anti-inflammatory property both inherently and because they help stabilise blood sugar, says Dr. Sowa. And, Alzheimer’s, the leading cause of dementia, is characterised by inflammation in the brain.
Overall, there's a lot more research that needs to be done on what exactly GLP-1s do in the brain. What we know—from doctors who prescribe it—is that early research is exciting, yielding preliminary findings about curbing ultra-processed food cravings, aiding addiction recovery, and even warding off dementia—with hopefully more to come from this drug that operates between your brain and your body.
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