6 Common Side Effects of Taking GLP-1 Medication

With nearly half of Americans saying weight loss is a goal for them, it’s no wonder that interest in GLP-1 medications has been on the rise. GLP-1 (short for glucagon-like peptide-1) medications are meant to help manage blood sugar levels and appetite, and they have changed the landscape of diabetes management and weight loss in recent years. While these medications can be beneficial for some, they can also come with unpleasant side effects like nausea, constipation and fatigue. 

While these side effects are common, they can be quite disruptive to daily life if left unchecked for too long. If your symptoms start to feel unmanageable, contact your health care provider for personalized advice. Whether you’re new to GLP-1 medications or seeking better ways to handle your side effects, we are bringing you tips to help you stay on track with your health goals while feeling your best.

1. Constipation

These medications can slow digestion, which can sometimes result in fewer or more difficult bowel movements. “To manage constipation, focus on two essential elements: fiber and hydration,” says Ana Pruteanu, M.S., RDN, CEDS-C, LDN. Fiber-rich foods like lentils, chickpeas, whole grains and vegetables help bulk up stool, making it easier to pass. And hydration is equally important. “Hydration helps soften stool and supports the fiber in doing its job,” adds Pruteanu. Bring a water bottle with you to make it easy to sip throughout the day. This can help you meet your daily water intake needs and help keep things moving smoothly. 

If your constipation lasts for more than three days, speak with your doctor about options to help. You might need to add a stool softener, or reduce your GLP-1 medication dosing until your gastrointestinal system can tolerate the side effects.

2. Diarrhea

“While constipation may be an issue for some, others may experience diarrhea while taking GLP-1 medications,” comments Lisa Andrews, M.Ed., RD, LD . Due to an aptly named phenomenon called dumping syndrome, slowed digestion can lead to pressure in the upper gastrointestinal tract, which triggers a release of stool in the lower GI tract, causing loose stools. “A bland diet that limits excessive fiber and includes plenty of fluids may help. Avoid foods such as dried fruit or sugar-free foods that could contain sugar alcohol, which can exacerbate diarrhea for some,” recommends Andrews. 

If you’re experiencing diarrhea, eat small meals and snacks that are low in fat to reduce the time they spend in the stomach. Remember, GLP-1 medications slow down digestion, so you might need to revisit your dosing with your doctor if symptoms persist. 

3. Low Appetite

GLP-1 medications work by suppressing appetite, which can uniquely be both a benefit and a challenge. It’s important to ensure you’re still meeting your nutritional needs, even if you don’t feel as hungry. Small, frequent meals that are nutrient-dense can help—focus on protein and produce first. “Smoothies are a great option, allowing you to blend together protein-rich Greek yogurt, fruits and a handful of greens. Snacks like hard-boiled eggs, cottage cheese or hummus with veggies provide a boost of protein and energy,” recommends Pruteanu.

4. Nausea

Nausea is one of the most frequently reported side effects when starting a GLP-1 medication, due to slowed-down digestion. Nausea may be related to overeating while taking these medications as well. Keep in mind that nausea should go away after you adjust to the medication for a couple weeks, and it should subside after the first few days following your subsequent injections.

That said, it can be more manageable with a few simple strategies. Firstly, get ahead of it. Nausea snowballs with time—eat early and eat often. Even if nausea is affecting your appetite and you’re only able to take a few bites, having something in your stomach can help prevent nausea from worsening. When eating, choose low-fat meals and smaller portions. “Large portions and high-fat foods can be difficult to tolerate due to the way GLP-1 medications slow digestion and enhance feelings of fullness,” says Sheila Patterson, RD, CDCES, founder of The Sugar Dietitian. 

She recommends practicing mindful eating techniques, slowing down your eating pace, paying attention to your body’s hunger and fullness cues, and stopping eating when you feel comfortably full. As with any symptom that feels too intense, discuss your nausea with your health care provider if it is interfering with your daily life.

5. Fatigue

Feeling tired during GLP-1 treatment is common as your body adjusts to taking in significantly fewer energy sources. Combating fatigue starts with fueling your body properly. Eating small, protein-rich meals helps maintain steady blood sugar levels and helps provide sustained energy. If you have trouble eating enough protein, consider a protein supplement while on your weight-loss journey. 

“To boost your energy levels, set reminders to eat small, protein-rich meals every three to four hours to help keep blood sugar steady. Setting reminders and staying on a meal schedule can also be helpful if you have a reduced appetite, to ensure you take in the nutrients your body needs,” advises  Melissa Mitri, M.S., RD.

6. Reflux

Reflux, or heartburn, can be an uncomfortable side effect of GLP-1 medications, as these drugs slow the digestive process, causing food to stay in the stomach longer.  “It’s helpful to limit or avoid common triggers, such as coffee, caffeine, alcohol, carbonated drinks, certain spices and acidic foods like tomatos and citrus if they bother you—especially in the few days following injection. Speak to your health care provider about taking over-the-counter antacids if dietary changes do not alleviate symptoms,” says Lauren Harris-Pincus, M.S., RDN, author of The Everything Easy Pre-Diabetes Cookbook.

If dietary changes don’t fully alleviate heartburn symptoms, speak with your health care provider about the possibility of using an over-the-counter antacid. With time, your digestive system may adapt, but these adjustments can help reduce discomfort in the meantime.

Other Healthy Eating Tips While Taking GLP-1 Medication 

An overall healthy lifestyle is crucial for supporting weight loss, whether or not you’re taking a GLP-1 medication. Here are some healthy eating tips to help support your goals: 

• Choose lean proteins: Stick to lower-fat protein choices like chicken, lower-fat fish, pork chops or tofu to avoid exacerbating nausea or reflux.
• Incorporate movement: Gentle activities like walking after meals can support digestion and reduce symptoms like reflux or bloating.
• Plan ahead: When your appetite is low, preparing balanced meals and snacks in advance can make it easier to stay on track and meet your nutritional needs despite feeling less hunger.
• Monitor symptoms: Keep a food and symptom journal to identify specific triggers or patterns unique to your experience. This is helpful to share with your prescribing health care provider, too.

The Bottom Line

Taking a GLP-1 medication can come with both positive and negative side effects, but they can be more manageable with the right strategies. By focusing on a nutrient-rich diet, staying hydrated and listening to your body, you can navigate symptoms like nausea, fatigue and constipation effectively. Always consult your health care provider for personalized advice and adjustments to your treatment plan if you feel your symptoms are unmanageable or too intense.