Literally every day I read something about Glucagon Like Peptide-1Receptor Agonists, GLP-RA’s. That’s the million dollar name for the class of drugs shamelessly called “the fat shot.” GLP-1’s have taken America by a storm greater than Hurricane Katrina without all the devastation. The only things devastated by GLP-1’s are the waistlines of the millions of people who have lost weight because they’ve taken the drugs for several months. Tirzepatide is leading the pack of prescriptions for GLP-1’s to the delight of every employee and stockholder of Eli Lilly and Co.
These drugs are incredibly profitable because the market for their use is so vast. Obesity is a worldwide epidemic with Americans somewhere in the top contenders for the most overweight population. And GLP-1’s do what they say they are supposed to do quite effectively. They claim users of GLP-1’s can lose up to 25% of their body weight so if you weigh 250 lbs., you can anticipate losing over 60 lbs. We all know people who claim to lose 55lbs., 87lbs., or an amount greater than 25% of their original weight. We see clear evidence they work!
Along with appetite suppression and weight loss, GLP-1’s are plagued with adverse effects that involve nearly every human organ system. The lungs, cardiovascular system, GI tract, liver and bile ducts, pancreas, kidneys, joints, and central nervous system all have had multiple reports of problems. These “problems” result from the anti-inflammatory effects of the drug class.
Gastrointestinal symptoms are the most common of the problems—nausea, vomiting, constipation, diarrhea, and abdominal discomfort are common. The number one reason patients stop taking GLP-1’s is nausea, followed by vomiting and diarrhea. GLP-1’s slow the movement of food material from the stomach through the small bowel and colon so patients feel full quickly and can’t finish a meal. Constipation, abdominal discomfort and pain occur frequently.
The liver, gall bladder, and bile ducts are susceptible to these drugs with the risk of gallstones being increased. Gall bladder inflammation (cholecystitis), bile duct inflammation (cholangitis), and pancreatitis are more serious adverse events.
In one study, fatigue was the second most commonly reported symptom, but in more current studies, it has not been reported enough to be a concern. The same study reported 4% of users had “reproductive symptoms” which are irregular periods, heavy bleeding, and intermenstrual bleeding.
Vision problems, especially in diabetic patients, can be very common. Sudden, painless vision loss from “non-arteritic anterior ischemic optic neuropathy” is a potentially serious problem. Lack of adequate blood flow to the optic nerve causes injury to the nerve and swelling of the retina, but despite strong suspicion, numerous studies have failed to prove GLP-1’s are the cause.
Most diabetics have some degree of chronic kidney disease. Those patients with “severe kidney impairment” are more likely to have the many adverse GI effects associated with GLP-1’s.
When semaglutide and terzepatide are compared, both cause nausea, fatigue, vomiting, constipation, and diarrhea, but with semaglutide, nausea and vomiting are reported by an additional 8%-11% of study participants.
Older adults, have high GLP-1 discontinuation rates. After 24 months of use, 68.2% of patients under 65 had stopped GLP-1’s. Those aged 65-74 quit 75.3% of the time, while those over 75 years quit 82.6% of he time. Bone loss and muscle mass loss affect the elderly as well, and lead to discontinuation. Cost, variable weight loss, and GI effects are reasons for stopping.
Another reference stated the assertions that GLP-1’s cause thyroid cancer, increase the risk of suicide, and cause pancreatitis are untrue and refuted by clinical studies. If a patient has a personal or family history of medullary thyroid cancer, however, GLP-1’s are contraindicated. There is no proven association of GLP-1’s causing thyroid cancer.
Like any drug class, GLP-1’s aren’t benign despite the incredible positive results patients experience. Along with those positive results must come some negative aspects. Patients lose weight with GLP-1’s because they aren’t hungry and don’t eat. In my brief experience, as a patient taking tirzepatide, I have very little appetite and almost feel nausea. My stomach constantly feels full, I can’t make myself eat, and I’m constipated. I’ve thrown away food that I previously would have finished. I don’t know how much I’ve lost, but I know I am losing because my clothes are looser.
I’ve taken 4 doses (4 weeks) of 2.5 mg, 3 doses (3 weeks) of 5 mg, and am noticing all the symptoms mentioned already. The maintenance dose is usually 10 mg or 12.5 mg weekly, so I have a way to go to reach maintenance. I expect the symptoms I’m having will only get worse as the weight melts away. I hope I’m able to see it through. I don’t mind the injections as the drug is administered with a pen-like injection device, and the needle stick is barely noticeable. I’ll keep you up to date on my progress and any adverse symptoms I encounter.
References: Spiriano P. GLP-1 Drugs Under Scrutiny: How Real Are the Risks? Medscape 2026 April 6.
Paauw DS. Myth of the Month: GLP-1’s Have Many Dangerous Side Effects. Medscape 2026 April 2.
Talwadeker M. FDA Data Reveal Different Risks for GLP-1’s. Medscape 2026 April 2.
Larkin M. Reddit Analysis Uncovers Unreported GLP-1 Side Effects Medscape 2026 April 16.
