Semaglutide, a weight loss injection, helped people with schizophrenia lose an average of 10.1 kg (22 pounds) over 24 weeks, according to a 2026 research study. Gram Research analysis found that participants maintained about half this weight loss one year after treatment ended, suggesting the medication requires ongoing use to sustain benefits. The study also detected changes in gut bacteria that may relate to improved health outcomes.
A new study shows that semaglutide, a weight loss medication, helped people with schizophrenia who were taking antipsychotic medications lose significant weight. Over 24 weeks, participants lost about 10% of their body weight on average. The study also found changes in gut bacteria that might be connected to better health. However, when people stopped taking semaglutide, they regained some of the weight. This research suggests the medication could help address weight gain that often happens with certain psychiatric medications.
Key Statistics
A 2026 study of 26 people with schizophrenia found that semaglutide produced a 9.8% body weight reduction over 24 weeks, with participants losing an average of 10.1 kg compared to their baseline weight.
Among the 17 participants who completed the full 24-week semaglutide intervention, waist circumference decreased by 7.3%, indicating significant reduction in abdominal fat.
At 76-week follow-up, participants maintained an average weight loss of 5.3 kg (5.1% of baseline), demonstrating that approximately half the weight loss persisted after discontinuing semaglutide.
The 2026 research found that microbial diversity in the gut decreased with semaglutide use, with enrichment of Parasutterella excrementihominis bacteria, suggesting potential biological mechanisms underlying weight loss.
The Quick Take
- What they studied: Whether semaglutide (a weight loss injection) could help people with schizophrenia lose weight while taking antipsychotic medications that often cause weight gain
- Who participated: 26 adults with schizophrenia (average age 41.5 years, 65% women) who were overweight and taking either clozapine or olanzapine, two common antipsychotic medications
- Key finding: People who completed the 24-week treatment lost an average of 10.1 kg (about 22 pounds), representing a 9.8% reduction in body weight. This benefit partially decreased after stopping the medication, with a 5.3 kg loss maintained at 76 weeks.
- What it means for you: If you have schizophrenia and struggle with weight gain from your psychiatric medications, semaglutide might help you lose weight. However, the weight loss requires ongoing treatment, and you should discuss this option with your doctor to see if it’s appropriate for your situation.
The Research Details
This was an open-label study, meaning both the participants and researchers knew who was receiving semaglutide. Participants received the medication through injections once per week for 24 weeks, starting with a lower dose that gradually increased to the full dose. The study tracked weight, waist size, blood sugar levels, and gut bacteria at the beginning, during treatment, and for one year after treatment ended.
The researchers used a real-world setting in a public mental health clinic, which means the results reflect what might happen in typical medical practice rather than in a controlled laboratory. They measured body composition using special scanning technology and analyzed stool samples to examine changes in gut bacteria.
This research approach is important because people with schizophrenia often gain significant weight from their psychiatric medications, which increases their risk of heart disease and diabetes. Testing semaglutide in this specific population helps doctors understand whether a weight loss medication can safely help this group without interfering with their psychiatric treatment. The inclusion of gut bacteria analysis provides insight into biological mechanisms that might explain how the medication works.
The study had some limitations that readers should know about: it was relatively small (26 participants), and only 65% completed the full 24-week intervention. There was no comparison group taking a placebo, so we can’t be completely certain the weight loss was entirely due to semaglutide rather than other factors. However, the results were statistically significant and the study was conducted in a real clinical setting, which increases its practical relevance.
What the Results Show
During the 24-week treatment period, participants lost an average of 10.1 kg (9.8% of their body weight), with waist circumference decreasing by 7.3%. These results were statistically significant, meaning they’re unlikely to have occurred by chance. The weight loss was substantial enough to potentially reduce health risks associated with obesity.
When researchers followed participants for an additional 52 weeks after treatment ended, the weight loss partially persisted. At the 76-week mark (one year after starting treatment), participants had maintained an average loss of 5.3 kg (5.1% of their baseline weight). This suggests that while some weight was regained after stopping the medication, participants didn’t return to their starting weight.
The study also examined blood sugar control using a measure called HbA1c, which reflects average blood sugar over three months. While there was a trend toward improvement, this change wasn’t statistically significant, meaning it could have occurred by chance. This suggests semaglutide’s primary benefit in this population is weight loss rather than blood sugar control.
An interesting secondary finding involved changes in gut bacteria. The diversity of bacteria in participants’ guts decreased as they spent more time on semaglutide. One specific type of bacteria, called Parasutterella excrementihominis, became more abundant. While the researchers suggest these changes might be associated with health improvements, the study didn’t directly measure whether these bacterial changes improved health outcomes. This finding opens the door for future research to understand how semaglutide affects the gut and whether these changes matter for overall health.
Previous research has shown that antipsychotic medications like clozapine and olanzapine frequently cause weight gain, sometimes 10-15 kg or more. This new study adds to growing evidence that semaglutide can help counteract this medication-related weight gain. However, most previous semaglutide studies focused on people without schizophrenia or other serious mental illnesses, so this research fills an important gap by showing the medication can work in this specific population without interfering with psychiatric treatment.
The study had several important limitations. First, it was small with only 26 participants, and one-third didn’t complete the full treatment period. Second, there was no control group receiving a placebo, so we can’t completely rule out that some weight loss came from increased attention to health or other factors. Third, the study was open-label, meaning participants knew they were receiving an active medication, which could influence their behavior and results. Fourth, the study didn’t measure whether weight loss improved psychiatric symptoms or quality of life. Finally, the study was conducted in one setting, so results might differ in other populations or healthcare systems.
The Bottom Line
According to Gram Research analysis, semaglutide appears effective for weight loss in people with schizophrenia taking antipsychotic medications (moderate confidence level based on this single study). If you have schizophrenia and are struggling with weight gain from psychiatric medications, discuss semaglutide with your psychiatrist or primary care doctor. The medication requires ongoing use to maintain weight loss benefits. It should be combined with healthy eating and physical activity when possible. Regular monitoring of weight, blood sugar, and psychiatric symptoms is important.
This research is most relevant for people with schizophrenia who are overweight or obese and taking clozapine or olanzapine. It may also be relevant for people taking other antipsychotics that cause weight gain, though this specific study only tested clozapine and olanzapine. People with schizophrenia and diabetes should discuss semaglutide with their doctors, as the study excluded people with diabetes. This research is less relevant for people without serious mental illness, as other weight loss approaches might be more appropriate.
Based on this study, you could expect to see meaningful weight loss within 24 weeks of starting semaglutide, with the most significant losses occurring during the first few months. However, weight loss typically continues throughout the 24-week period. After stopping the medication, expect some weight regain, though the study suggests you may maintain about half of the weight loss achieved during treatment. Individual results will vary, and combining medication with lifestyle changes may improve outcomes.
Frequently Asked Questions
Can semaglutide help with weight gain from antipsychotic medications?
Yes, according to a 2026 study, semaglutide produced significant weight loss in people taking clozapine or olanzapine, with participants losing an average of 10.1 kg over 24 weeks. However, weight loss requires ongoing medication use, as benefits partially diminish after stopping treatment.
How much weight can I expect to lose with semaglutide if I have schizophrenia?
The study showed an average weight loss of 9.8% over 24 weeks, which equals about 10 kg for someone weighing 100 kg. Individual results vary, and combining medication with healthy eating and exercise may improve outcomes. Results depend on your starting weight and adherence to treatment.
Will I keep the weight off after stopping semaglutide?
Partially. The 2026 research found that participants maintained about 5.3 kg of their 10.1 kg weight loss one year after stopping semaglutide. This suggests some weight regain occurs, but not a complete return to baseline weight. Long-term lifestyle changes help maintain results.
Does semaglutide affect psychiatric symptoms or antipsychotic medication effectiveness?
This study didn’t specifically measure psychiatric symptom changes, so we don’t have clear evidence either way. The research focused on weight and metabolic changes. Anyone considering semaglutide should discuss potential interactions with their psychiatrist before starting treatment.
What changes happen to gut bacteria when taking semaglutide?
The study found that gut bacterial diversity decreased and a specific bacteria called Parasutterella excrementihominis became more abundant during semaglutide treatment. Researchers suggest these changes may relate to health improvements, but the study didn’t directly measure health benefits from these bacterial changes.
Want to Apply This Research?
- Track weekly weight and waist circumference measurements. Record the specific dose of semaglutide you’re taking each week and any side effects. Monitor appetite changes and food intake patterns. Track psychiatric symptom stability to ensure the medication doesn’t interfere with mental health treatment.
- Use the app to set a realistic weight loss goal (aim for 1-2 pounds per week). Log meals to increase awareness of eating patterns. Set reminders for weekly semaglutide injections. Track physical activity, even light movement like walking, which can enhance weight loss results.
- Establish a baseline weight and measurements before starting semaglutide. Weigh yourself weekly at the same time of day and record in the app. Take waist circumference measurements monthly. Schedule regular check-ins with your doctor (every 4-8 weeks) to monitor progress and adjust treatment if needed. After stopping semaglutide, continue tracking weight monthly for at least 6 months to monitor for regain.
This research summary is for educational purposes only and should not replace professional medical advice. Semaglutide is a prescription medication that requires medical supervision. If you have schizophrenia or another serious mental illness and are considering semaglutide for weight loss, discuss this option with your psychiatrist or primary care doctor before starting treatment. Do not start, stop, or change any psychiatric medications without consulting your healthcare provider. This study was relatively small and had limitations; more research is needed to fully understand semaglutide’s safety and effectiveness in people with schizophrenia.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.