The Most Common GLP-1 Side Effects — and How to Cope

Glucagon-like peptide-1 (GLP-1) medications have changed the game when it comes to treating obesity or type 2 diabetes. Semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro, Zepbound), and orforglipron (Foundayo) can improve blood sugar levels, cause meaningful weight loss, and deliver a big boost to overall metabolic health.

But GLP-1s typically come with side effects or other issues. These can vary widely, ranging from digestive problems like nausea and constipation to appearance-related concerns like temporary hair thinning and so-called “Ozempic face.”

This doesn’t mean significant discomfort is something you’re expected to endure indefinitely. “No one should suffer in the process of weight loss,” says Yuval Pinto, MD, an obesity and family medicine doctor at Johns Hopkins Medicine in Baltimore.

Learning which side effects are typical (and manageable) and which ones are severe enough to require medical attention can help you use GLP-1s safely and get the most benefit.

Nausea and Vomiting

Because GLP-1 drugs cause the stomach to empty more slowly, large meals — particularly those with high-fat foods — may be harder to tolerate. Eating quickly or continuing after you feel full can also trigger symptoms, Dr. Pinto says.

Constipation and Diarrhea

The slowed rate at which food moves through the digestive system helps explain constipation. Diarrhea also occurs with GLP-1s, although exactly why isn’t as clear, Pinto says.

Reflux, Bloating, Abdominal Pain, and “Sulfur Burps”

Some changes that occur while you’re taking a GLP-1 aren’t caused directly by the medication. Instead, losing weight (particularly if it happens quickly) along with eating much less or becoming dehydrated can trigger symptoms, says Pinto.

Hair Shedding

“GLP medications are not known to affect hair follicles directly,” says Tonia Yee Vinton, MD, an endocrinologist at the University of Texas Southwestern Medical Center in Dallas who specializes in obesity, metabolic syndrome, and preventive medicine. Rapid weight loss, reduced calorie intake, nutritional deficiencies, and stress are more likely triggers for GLP-1-related hair loss, she says.

A common pattern is telogen effluvium, the medical term for temporary shedding that typically begins two to three months after a physical stressor and usually goes away within six to nine months once the underlying problem is addressed, says Dr. Vinton.

Facial Volume Loss (Ozempic Face)

Fatigue and Headaches

If a patient is experiencing these issues, Pinto considers other possible causes rather than automatically blaming the GLP-1. Not eating enough food or not drinking enough fluids during treatment can contribute to fatigue, headaches, dizziness, and low blood pressure.

You don’t have to simply push through side effects. Eating differently, tracking symptoms, and keeping your prescriber informed can make treatment easier to tolerate.

Be Mindful About How You Eat and Drink

While you may not be able to avoid GI side effects completely, a few simple habits can help lessen their impact, says Natasha Pyfrom, MD, a primary care physician who treats people with obesity at Atrium Health Primary Care Shiland Family Medicine in Rock Hill, South Carolina.

Dr. Pyfrom recommends that you:

• Eat smaller portions.
• Eat slowly and stop eating when you’re full.
• Limit foods that consistently trigger symptoms, such as spicy foods and fried foods. “Tracking the relationship between food choices and symptoms can be helpful,” she says.
• Drink plenty of water.

Speak Up Before Your Next Dose Increase

If side effects are an issue, make sure you tell your doctor — especially before moving up in dose, says Pinto. Your clinician may recommend staying at the current dose longer or making another adjustment.

If you’re losing weight so quickly that it’s resulting in hair shedding or Ozempic face, you might also want to ask your clinician about dialing down your GLP-1 dose to reduce stress on your body.

Keep a Symptom Diary

Pyfrom recommends tracking meals and symptoms to identify patterns. Include your dose day so you and your prescriber can see whether certain foods, portions, or dose changes seem to cause problems.

Protect Your Nutrition

Reduced appetite is expected, but you should still be able to eat enough to meet your nutritional needs and avoid deficiencies that can worsen issues like hair shedding.

Excessive appetite suppression, nausea, or vomiting that prevents adequate nutrition intake is a reason to discuss your dose with your prescriber, says Vinton.

Ask Before Treating Side Effects on Your Own

Before routinely adding a stool softener (to alleviate constipation), antacid (for reflux), or antinausea medication, talk to your doctor, says Pinto.

“A patient who does not tolerate one medication may do very well on another, so having side effects with one GLP-1–based treatment does not necessarily mean the entire class is off the table,” says Pyfrom.

Severe complications from GLP-1 use tend to be rare, but they can happen.

Pancreatitis

Acute pancreatitis (sudden swelling and inflammation of the pancreas, the organ that produces hormones like insulin) can occur in people taking GLP-1 medications and appears in current prescribing-information warnings, although reviews of randomized trials have not established a clear increase in pancreatitis risk.

Gallbladder Problems

Dehydration and Kidney Stress

Hypoglycemia

Pinto recommends contacting your healthcare provider and/or seeking emergency care if you have:

• Repeated vomiting or can’t keep food or fluids down
• Severe diarrhea or signs of significant dehydration, such as extreme dizziness
• Severe or persistent upper abdominal pain, particularly pain that spreads to the back
• Right upper abdominal pain with fever, jaundice, or dark urine
• Severe constipation accompanied by abdominal pain or vomiting