The Side Effects That Often Make People Quit Weight Loss Drugs, According to Experts
Recently, Mounjaro was licensed as a weight loss drug in the UK, and can now be prescribed by your GP. For some, this is akin to a miracle drug, but for others, it can be a source of frustration.
Medications like Wegovy (Semaglutide) and Mounjaro (Tirzepatide) are transforming the fight against obesity, helping many lose weight, manage blood sugar, and reduce their risk of chronic disease. But despite these drugs’ effectiveness, not everyone sticks with them. According to experts, certain side effects cause some patients to give up on the drugs entirely.
We spoke with our expert Paul, MPharm, a clinical pharmacist from Optimal You https://optimalyou.co.uk/, to understand why people are walking away from two of the most powerful tools in modern weight loss.
The Side Effects That Drive People to Quit
“The number one reason patients stop taking Wegovy or Mounjaro is gastrointestinal distress,” says Paul. “The nausea, vomiting, diarrhea, and constipation can be really intense, especially if a dose is increased too quickly.”
Both drugs work by mimicking hormones that help regulate appetite and blood sugar, but that same mechanism that makes them work also slows digestion, and for some this causes persistent and uncomfortable symptoms.
Up to 50% of reported users of GLP-1-based drugs stated they experienced nausea severe enough to consider discontinuing the drug. While many experience relief within weeks, others find the symptoms too disruptive to tolerate.
Dosing Too Fast, Feeling Too Sick
Paul warns that rushing the dosing schedule is a major mistake that increases the chance of quitting early.
“Both Wegovy and Mounjaro are designed with gradual dose escalation, but patients often want to jump to the higher dose to see faster results,” he says. “That’s when the side effects really kick in.”
He advises starting at the lowest dose and moving up slowly and always following the advice of your GP, even if weight loss plateaus temporarily. “Ultimately, it’s not a race. The goal is to help the body adapt.”
Other Side Effects That Lead to Dropout
While GI symptoms are the most common deal-breakers, Paul points to a few other side effects that can also drive patients off the drugs:
* Fatigue and low energy: Especially in the early weeks, due to reduced caloric intake.
* Bloating or early satiety: Some patients feel uncomfortably full after very small meals.
* Gallbladder issues: Including gallstones, often related to rapid weight loss.
* Mood changes: Rare but some patients do report stronger emotions or increased anxiety.
He also notes reports of hair thinning, though this is typically a side effect of speedy weight loss itself rather than the drugs directly.
Can These Side Effects Be Managed?
Fortunately, most side effects are manageable with proper support.
“Simple changes, like eating smaller meals, staying hydrated, and avoiding fatty foods can make a big difference,” says Paul. “And if side effects persist, we can adjust the dose or pause treatment temporarily.”
He encourages patients to report side effects early and keep in regular contact with their GP. “Don’t suffer in silence. Small tweaks can make the difference between quitting and success.”
Wegovy vs. Mounjaro: Is One Easier to Tolerate?
Some patients ask if one drug is gentler than the other, but it depends on the individual. Both medications are highly effective, helping patients lose, on average, 15–20% of their body weight, but choosing the right one can come down to how the body handles side effects.
Final Advice: Patience Pays Off
For those just starting their journey with Wegovy or Mounjaro, our expert, Paul, offers this advice:
1. Stick to the titration schedule.
2. Manage expectations.
3. Communicate with your GP.
4. Treat it like a marathon, not a sprint and stay consistent.
“These medications are powerful, but they’re not magic. The patients who succeed are the ones who listen to their bodies and GPs, stay patient, and don’t give up.”