A large-scale analysis of social media posts is providing a new perspective on what people taking GLP-1 for diabetes or obesity are experiencing in real life.
The study results do not prove that the drug caused these symptoms, but the authors say this pattern may warrant further study.
“These are signals, not conclusions, but they’re worth paying attention to because they come directly from patients, unprompted,” says lead author Neil Sehgal, a doctoral student at the University of Pennsylvania in Philadelphia.
But some experts aren’t convinced the findings are worth further study, given the anonymous nature of Reddit posts.
Research using AI to analyze real patient reports
To better understand how people experience GLP-1 drugs outside of clinical trials, researchers used AI to analyze Reddit posts from 2019 to 2025.
They identified approximately 70,000 users who said they were taking drugs such as semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound). Approximately 44 percent of these users reported at least one side effect.
Many of the most commonly reported symptoms, such as nausea, vomiting, and constipation, mirror those reported by participants in clinical trials.
Some symptoms reported online are not commonly seen in clinical trials
Symptoms reported online but not commonly documented in GLP-1 trials include:
- About 4 percent of users who reported side effects mentioned menstrual changes such as irregular cycles, heavy bleeding, or spotting between periods.
- Approximately 17% of users reported fatigue.
- Temperature-related complaints such as chills, chills, and hot flashes were each reported by 1% to 4% of people.
While the study is interesting as a computer science paper, its methods and results don’t stand up to scrutiny from medical science, said Yuval Pinto, M.D., a physician in obesity and family medicine at Johns Hopkins School of Medicine in Baltimore.
The data comes from an open, anonymous platform, so researchers cannot confirm who is posting or whether users are accurately reporting their drug use or symptoms, said Dr. Pinto, who was not involved in the study.
“We also have no way of knowing whether these posts are from people who are currently taking GLP-1, how long they have been taking it, any other co-morbidities, or even other medications they are taking that may be causing these side effects,” he says.
The survey results should be taken with a grain of salt.
The findings draw attention to symptoms that are not consistently reported in GLP-1 clinical trials or do not meet the criteria for reporting, the authors wrote. In other words, trial participants may report certain symptoms, but researchers may conclude that it doesn’t matter because people receiving the placebo (dummy treatment) have the same experience.
For example, fatigue has been reported in some GLP-1 trials. One meta-analysis found that about 7.5 percent of people taking GLP-1 reported fatigue, as did 5 percent of participants taking a placebo.
But it’s worth pointing out that the Reddit study didn’t have a placebo group, Pinto said. Although a significant number of people taking GLP-1 experienced fatigue, it is not clear how many comparable people not taking GLP-1 report that symptom.
A number of placebo-controlled trials that track symptoms are being conducted to ensure this data is being collected, Pinto said. Across randomized clinical trials of GLP-1 drugs involving thousands of participants, the most common side effects are consistently stomach-related and include nausea, diarrhea, constipation and vomiting, he says.
“This is consistent with what I’ve seen in my practice: people consistently report these gastrointestinal symptoms and rarely report other symptoms,” he says.
Pinto said when people experience symptoms that are outside the norm, they are often unrelated. “People tend to attribute symptoms to the most recent event in their life, even when there is no connection,” he says.
Some symptoms and changes may be due to weight loss rather than GLP-1. “For example, some women find it easier to get pregnant after losing weight, but that’s not a side effect of GLP-1,” he says.
The same goes for hair removal. “Rapid weight loss can cause temporary hair loss, but it’s not directly caused by the drug,” Pinto says.
What this means for people taking GLP-1 drugs
The researchers hope their findings will encourage doctors and researchers to take a closer look at the side effects patients are discussing online.
“They’re clearly in the patient’s mind, and that’s worth paying attention to,” Sehgal says.
Pinto agrees that people should feel empowered to talk to their health care providers about the symptoms they’re experiencing.
“Your doctor is in the best position to know your medical history, the dosage of GLP-1, how long you’ve been taking it, and other medications you’re taking, which are important factors that may affect your symptoms,” he says.
