This article will appear in the forthcoming fall issue of Johns Hopkins Magazine.
The food noise stopped.
It's a common response from people taking GLP-1 receptor agonists, referring to the relentless internal monologue that once revolved around food cravings: A few chips won't hurt. Someone left cookies in the break room.
For many, that chatter silences soon after starting a GLP-1 such as Ozempic, Wegovy, or Zepbound. These drugs mimic a natural hormone, GLP-1, secreted in the gut after meals. The hormone slows digestion, stimulates the pancreas to release insulin, and signals to the brain a sense of fullness. Over time, less hunger and fewer intrusive thoughts about food often lead to sustained weight loss.
Originally developed to treat Type 2 diabetes, GLP-1s are soaring in popularity. One in eight Americans takes one, a KFF poll from 2025 found. Analysts predict demand will keep rising sharply, not just in the U.S., where changes in Medicare and Medicaid coverage are expanding access and lowering costs, but also worldwide, where the global market could reach $190 billion by 2035.
G. Caleb Alexander, a professor of epidemiology and medicine at theJohns Hopkins Bloomberg School of Public Health, prescribes and manages GLP-1s for patients. He also serves as founding co-director of theJohns Hopkins Center for Drug Safety and Effectiveness, where he studies the use of GLP-1s and other medications in real-world settings. Recently, he made a key finding: GLP-1s help people shed pounds, regardless of their age, race, ethnicity, diabetes status, and starting weight, but they do so for women moderately more than men. His results, published in JAMA Internal Medicine, suggest a possible synergistic interaction with estrogen, but more research is needed to know for sure.
To Alexander, "These drugs are transformative-a real game changer," he says. "After decades of exhaustive searches for a successful weight-loss drug, we've found one that appears to be remarkably safe and effective."
Diabetes patients have been taking GLP-1s for decades. But as more individuals use these products indefinitely, the new prevalence raises questions about safety and side effects, both in the short term and years down the road.
What to know
"All medications come with risks and side effects," Alexander says. But in his clinic, most patients tolerate GLP-1s well. When side effects do occur, they can often be abated by reducing the dose, and many go away within a few months as the body grows accustomed to the drug, he says.
The most common are gastrointestinal: nausea, diarrhea, constipation, and abdominal pain. Other potential effects include dizziness, a faster heart rate, headache, and difficulty feeling joy, possibly owing to less pleasure from food.
To ease symptoms, Alexander tells patients to eat smaller, more frequent meals; avoid foods and drinks high in sugar and fat; stay hydrated; and consume fiber-rich foods.
A small number of patients experience side effects severe enough to stop treatment. Even so, Alexander says side effects explain only part of the drug's "astronomically high discontinuation rate." Studies show that roughly 50% to 75% of people quit taking the drug within the first year. "Intolerance is part of the picture, but several other reasons drive nonadherence," Alexander says. Costs and insurance coverage play a role. While most health insurances cover GLP-1s for Type 2 diabetes, fewer cover them for obesity and weight loss, leaving some patients to pay as much as $500 a month.
Alexander notes that discontinuation may also relate to efficacy. Although oral GLP-1s are typically less effective than injections, they offer a good alternative for patients who can't tolerate needles. Success involves following the old dosing adage: Start low and go slow. "Typically we titrate up the medicine slowly, and one should always settle for the lowest effective dose," Alexander says.
What happens when someone stops the drug? "Studies show that people tend to gain back the weight in about 18 months," he explains. Once the drug leaves your system, appetite rebounds, food noise returns, digestion speeds up, and your metabolism resets.
More serious consequences
Low blood sugar, or hypoglycemia, can occur in people with diabetes taking GLP-1s, particularly if they manage glucose levels with medicines such as insulin. "Hypoglycemia causes lightheadedness, fatigue, malaise, and confusion," Alexander says. "When severe, it can cause seizures." Talk to a doctor if you notice symptoms.
Gradual and significant muscle loss, or sarcopenia, can also occur, especially among the elderly and those who are already frail, he says. While some doctors recommend resistance and strength training for anyone taking a GLP-1, whether they lose muscle or not, Alexander doesn't consistently do so in his clinic. More research is needed.
Though rare, reports of pancreatitis, thyroid cancers, kidney damage, and gallbladder problems have surfaced. But these outcomes haven't been borne out by follow-up studies, he says, and shouldn't necessarily influence someone's decision to try the drug.
Added benefits
Other good news: Studies suggest GLP-1s show promise beyond weight loss, although teasing apart causation from correlation can be tricky. Potential perks include:
- Lowering blood pressure and risks for heart attacks, strokes, and other cardiovascular events
- Improving liver function and lowering inflammation in metabolic liver disease
- Decreasing overall cancer risk and significantly lowering risks for endometrial and ovarian cancers
- Lessening the severity of obstructive sleep apnea
- Curbing cravings and reducing relapse in addictions
- Easing joint pain and slowing cartilage damage in osteoarthritis
"The more we study, the more potential benefits we see in using GLP-1s to help address other health problems," Alexander says. Could this be a wonder drug, revolutionizing the treatment of more than diabetes and obesity?
Time will tell.
