GLP-1 has been hailed as a life-changing treatment for those looking to lose weight and adjust their relationship with food, but like any drug, it’s not without side effects. “As a family physician, I often see patients experience some predictable side effects when starting GLP-1 drugs, such as semaglutide or liraglutide,” says Elizabeth Kazarian, M.D., a family physician in Arlington, Virginia. “These side effects can be unpleasant, but they are usually manageable with proper guidance and adjustments.”
Not surprisingly, digestive problems tend to be most common, especially during the first few weeks as your body adjusts, says New York endocrinologist Rekha Kumar, M.D. “For most people, these are temporary, and with proper clinical support and a gradual approach to dosing, most people find that their symptoms quickly disappear and they can continue to meet their health goals.” Additionally, “with lower-dose approaches, such as microdosing, which many prevention-focused patients choose, these effects tend to be even milder,” he points out.
Below we list some of the most common side effects and solutions recommended by experts. However, it’s important to note that everyone responds differently to these drugs, Dr. Kazarian says, and you should always check with your doctor before starting or adjusting your GLP-1 dose. “Your care should be as individual as your health goals,” agreed Dr. Kumar, noting that at Found, where he serves as a medical advisor, patients receive personalized guidance. “You will never manage this alone.”
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Dr. Elizabeth Kazarian is a board-certified family physician in Arlington, Virginia. Dr. Rekha Kumar is a board-certified endocrinologist in New York State.
Pro tip: What and how you eat can affect GLP-1 side effects
“When it comes to GLP-1, how you eat is just as important as what you eat,” says Dr. Kumar. He says it’s important to focus on unprocessed, whole foods. “Eating slowly, in small portions, and avoiding heavy or fried foods can make a big difference in how you feel, especially at the beginning and on the day of treatment.”
“When using GLP-1, it’s also worth paying a little more attention to protein. Protein stabilizes energy, protects muscle tone, and helps you feel satisfied without discomfort,” says Dr. Kumar. But he points out that the protein fad could go too far. “Most women don’t need to achieve the grams lauded by many wellness influencers. Getting plenty of fiber from vegetables and fruits and staying hydrated can be just as important as protein, for example,” says Dr. Kumar. “These are the cornerstones of metabolic health whether you use GLP-1 or not.”
Most common GLP-1 side effects
nausea
Dr. Kazarian said nausea tends to be the most common side effect, especially in the first few weeks and during dose increases. “To relieve nausea, I encourage patients to eat less, avoid fatty and rich foods, and increase their dose slowly,” says Dr. Kazarian. Dr. Kumar offers similar advice, saying that if nausea occurs, it’s best to “continue eating simple, nutritious foods and spread your meals evenly throughout the day.”
digestive system problems
Dr. Kazarian says that while constipation is frequently reported, some people may experience diarrhea instead. “If you’re constipated, hydration and fiber are important. We recommend aiming for 25 to 30 grams of fiber per day through fruits, vegetables, whole grains, legumes, or fiber supplements if needed,” says Dr. Kazarian. “Gentle exercise, such as walking, can also aid digestion.” Dr. Kumar says you can also consider gentle over-the-counter solutions if needed. On the other hand, if diarrhea occurs, Dr. Kazarian says, “staying on a bland diet and avoiding caffeine and spicy foods may alleviate symptoms.”
loss of appetite
“Feeling full faster or having a lower appetite isn’t actually a side effect; it’s how the drug supports your metabolism,” says Dr. Kumar. However, Dr. Kazarian explains, “While a decrease in appetite is expected and often desired, in some cases it can be noticeable.” If you’ve completely lost your appetite, she recommends focusing on smaller but more nutritious meals like smoothies, soups, and high-protein snacks.
fatigue
Dr. Kazarian says fatigue and low energy levels can occur, especially if patients aren’t eating enough or staying hydrated. It may sound simple, but fatigue often improves when you address your hydration and calorie intake, she says. “Some patients experience mild fatigue and heartburn, especially after a rich meal, which is why nutrition is so important,” says Dr. Kumar. “It’s important to stay hydrated and maintain a consistent eating schedule. It helps prevent fatigue and keeps your energy consistent.”
