The amazingly effective pharmaceuticals used for weight loss, known as GLP-1s, may seem like a miracle, but, like most new drugs on the market, their side effects are still being discovered. For sure, these prescription drugs take away the food noise for most people, allowing patients to lose, in some cases, massive amounts of weight. Almost everyone taking the weekly injection of a myriad of GLP-1s can attest to its effectiveness. This week, results from an atypical survey of these patients were published, and lo and behold, some side effects not seen in the clinical trials emerged.
The survey asked Reddit posters about their experience with glucagon-like peptide-1 receptor agonists (GLP-1 RAs). They analyzed more than 400,000 posts from 67,000 users about their experience taking the drugs. Of those who took the medication, 44% reported some type of side effect.
Naturally, the majority of health issues associated with taking GLP-1s involve the gastrointestinal system. Known side effects, such as nausea and vomiting, were high on the list, as expected. What was surprising was that so many others not previously mentioned were common.
“These are signals, not conclusions — but they’re coming directly from patients, unprompted, and that’s worth paying attention to,” according to Neil Sehgal, one of the authors of the paper. A strength of this type of study is that the information comes from “real-world” patients. Here are some key findings:
13% experienced mental health changes that include depression and anxiety. Insomnia was also reported.
Close to 4% reported reproductive system changes (mostly irregular cycles in women)
Body temperature fluctuations, from hot flashes to chills.
5% claimed they suffered from acid reflux, headaches, and dizziness.
16% reported fatigue
Doctors point out that several of these side effects may be due to another condition, not the drug itself. If this sounds confusing, it is. For example, if someone is experiencing heart palpitations, it may be due to low blood pressure, not the prescription drug. As one Reddit poster intoned, “Being in a 600-1000 calorie per day deficit leads to fatigue. More news at 11.”
Yet another user noted many of the symptoms mentioned were a byproduct of starvation: “Sounds like symptoms of malnutrition which GLP-1s can cause when you aren’t eating enough.”
A criticism of this survey is that several weight-loss medications that weren’t GLP-1s, such as phentermine, were included in the study. As well, the Reddit population doesn’t exactly mirror the general population. Reddit users tend to be younger males.
GLP-1s and the $64,000 Question
Of course, the 800-pound gorilla, the question that everyone wants an answer to, is what will happen when a patient stops using a GLP-1. That’s where the traditional “watch your diet and remember to exercise” comes into play. For some who have lost considerable weight, it’s an opportunity to begin an exercise regimen in earnest. “I’ve lost 60lbs in a year (on/off monjaro) and am training for a marathon in May. I never would have developed my exercise habits without losing the first 40 or so lbs,” wrote one poster.
It must be noted that there were many side effects reported that were positive, like this one: “My side effect was that I, a heavy daily binge drinker, haven’t had a sip of alcohol since the day I took the first dose. I’ll take odd unknown side effects over slowly poisoning myself any day!”
To be sure, this was an unorthodox experiment, and the patterns found should be taken as stepping stones for additional research and not as gospel.









