What you’ll learn:
- GLP-1 medications help manage appetite and blood sugar, and slow digestion, making them widely used for both diabetes management and weight loss.
- Common side effects include nausea, vomiting, diarrhea, and constipation, which typically improve as your body adjusts to treatment.
- Symptoms vary by medication and dose, so working with your provider can help you manage side effects and find the best option for you.
GLP-1 medications have quickly become some of the most talked-about treatment options for weight loss and type 2 diabetes management. You might recognize names like Ozempic®, Wegovy®, Mounjaro®, and Zepbound®.
These medications work by mimicking one or more hormones in your body to help regulate appetite, manage blood sugar, and slow digestion. As more people explore these treatments, questions about what to expect, especially when it comes to side effects, are becoming more common.
And it makes sense why people are interested: GLP-1s don’t just support weight loss. A recent large-scale study involving people with a BMI over 30 found that these medications were linked to lower rates of heart disease, stroke, and kidney issues. The health benefits extended across multiple subgroups and locations, pointing to the broader potential of GLP-1 medications.
Here’s the tradeoff: While GLP-1 medications can be highly effective, they often come with side effects, particularly in the early weeks. Nausea, constipation, and fatigue are common. The good news? Many of these symptoms improve with time, and gradual dose increases (also called titration) can make a big difference in how your body adjusts.
Whether you’re already taking a GLP-1 medication or just considering it, knowing the possible side effects can help you feel more prepared. We’ll cover the most common symptoms, when they tend to show up, and tips to help manage them.
Why GLP-1 medications cause side effects
GLP-1 medications work by mimicking a hormone your body naturally makes called glucagon-like peptide-1. (That’s where the GLP-1 comes from.) Your body releases this hormone after eating and in response to other triggers, like physical activity or rising blood sugar levels, helping you feel full and keeping your glucose levels in check.
One of the biggest effects of GLP-1s is on appetite and digestion. These medications target the brain’s appetite centers to help reduce hunger and increase feelings of fullness. They also slow down how quickly food leaves your stomach, helping you feel satisfied longer and making it easier to eat smaller portions.
But because these changes directly affect how your digestive system functions, they can also lead to side effects, especially during the first few weeks as your body adjusts. Slowed stomach emptying can cause nausea, bloating, or even vomiting if food stays in your stomach too long. It can also contribute to constipation since digestion slows down overall. Some people experience diarrhea, likely due to how GLP-1s influence gut motility and fluid balance in your digestive tract.
A step-up dosing schedule will be planned to help minimize GLP-1 side effects. You’ll start on a low dose and gradually increase over several weeks or months.
GLP-1 side effects: When they’re most likely
You’re most likely to notice side effects during the first few weeks or right after a dose increase. Most people find that these symptoms start to ease once they adjust.
GLP-1 medications are started at a low dose and increased gradually over time to help reduce side effects. Not everyone needs to reach the maximum dose to see benefits. If a lower dose is working well for you, sticking with it is fine.
Here’s a brief overview of some of the more popular GLP-1 medications, their active ingredients, and their doses:
| Active ingredient | Medications & doses |
|---|---|
| Semaglutide | Ozempic®: 0.25 mg, 0.5 mg, 1 mg, 2 mg (weekly) Wegovy®: 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, 2.4 mg (weekly) Rybelsus®: 3 mg, 7 mg, 14 mg (daily, oral) |
| Tirzepatide | Mounjaro®/Zepbound®: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg (weekly) |
| Liraglutide | Saxenda®: 0.6 mg to 3 mg (daily) Victoza®: 0.6 mg, 1.2 mg, 1.8 mg (daily) |
| Dulaglutide | Trulicity®: 0.75 mg, 1.5 mg, 3 mg, 4.5 mg (weekly) |
| Exenatide | Byetta®: 5 mcg, 10 mcg (twice daily) Bydureon®: 2 mg (weekly) |
GLP-1 side effects: What people experience
Most GLP-1 medications come with similar side effects since they have very similar mechanisms of action. While the experience can vary from person to person, some symptoms are reported more often than others.
How often these show up—and how noticeable they feel—can depend on the specific medication and dose. The following sections give a quick overview of what people have reported with GLP-1 treatments as a whole and tips to help you handle them if they occur.
Digestive symptoms are the most common side effects people report when taking GLP-1 medications. One recent study of over 10,000 adults using GLP-1s looked at how often they experienced GI side effects across semaglutide (Ozempic® and Wegovy®), liraglutide (Victoza® or Saxenda®), dulaglutide (Trulicity®), and exenatide (Byetta® or Bydureon®).
Worth noting: Tirzepatide (Mounjaro® or Zepbound®) was not included in this study. While it leads to similar digestive symptoms, early research suggests it may have a slightly different side effect profile due to its dual mechanism of action.
Here’s how often the most common GI side effects showed up in the study:
| Symptom | % reported |
|---|---|
| Abdominal pain | 58% |
| Constipation | 30% |
| Diarrhea | 31% |
| Nausea and vomiting | 23% |
What else did the data tell us?
- Some medications—like dulaglutide and liraglutide—were tied to higher rates of these symptoms than others.
- While more serious effects like gastroparesis and pancreatitis were reported, they were rare, and the risk didn’t vary as much across medications.
- Females, younger adults, and people with conditions like chronic kidney disease or heart failure tended to report more GI symptoms.
All in all, the study reinforces that while digestive issues are common across all medications, your experience can depend on which GLP-1 you’re using, your health history, and how your body responds over time.
GLP-1 medications: Comparing side effects
If you’re exploring GLP-1 medications like semaglutide, tirzepatide, liraglutide, and dulaglutide, you’ll notice that while they share many similarities, each one can affect the body a bit differently. Side effects are generally similar, but their frequency and intensity vary depending on the specific active ingredient.
The table below focuses on the highest approved doses for each medication. Not everyone reaches the maximum dose, but this gives a useful snapshot of what some people experience over the course of treatment.
| Medication (dose) | Nausea | Vomiting | Diarrhea | Constipation | Dyspepsia (indigestion) | Key differences |
|---|---|---|---|---|---|---|
| Semaglutide (2.4 mg) – Wegovy | 44% | 24% | 30% | 24% | 9% | Highest rates of nausea, vomiting, diarrhea, and constipation compared to all others listed. |
| Tirzepatide (15 mg) – Mounjaro/Zepbound | 28% | 13% | 23% | 11% | 10% | Lower rates of nausea and constipation than semaglutide Diarrhea is slightly more common than with dulaglutide and liraglutide. |
| Liraglutide (3 mg) – Saxenda | 39% | 15% | 21% | 19% | 9% | Lower rates of vomiting and diarrhea than with semaglutide, but nausea is still relatively high. |
| Dulaglutide (4.5 mg) – Trulicity | 16% | 9% | 10% | Not reported | 2% | Lowest overall rates of GI side effects among all medications listed. |
Which GLP-1 has the least side effects when used for weight loss?
When it comes to taking GLP-1 medications for weight loss, side effects matter—especially when you’re committing to a long-term plan. The two most powerful options on the market—semaglutide (Wegovy®) and tirzepatide (Zepbound®)—are not only effective but generally well tolerated by most people. But which one had fewer side effects with the biggest benefits?
In clinical trials, Wegovy® helped people lose an average of 15% of their body weight over 68 weeks. Zepbound® showed even greater results, with an average loss of 22% at the highest dose over 72 weeks. Both medications can cause side effects like nausea, diarrhea, or fatigue, but these are usually mild and temporary.
When comparing the two, tirzepatide had slightly lower dropout rates due to GI symptoms (about 3%) compared to semaglutide (about 6%). Overall side effect rates were similar for both—around 77%—but most people were able to stay on both medications. Based on current research, tirzepatide appears to offer the best balance of weight loss results and tolerability among the newer GLP-1 options.
How long do GLP-1 side effects last?
Here’s a quick summary of what clinical studies say about how long the most common digestive side effects from GLP-1 medications typically last:
| Symptom | Typical onset | How long it lasts |
|---|---|---|
| Nausea | Most common in the first 4–5 weeks | Usually resolves within 8 days of starting |
| Vomiting | Often starts early in treatment | Lasts 1 to 8 days in most cases |
| Diarrhea | Common in the first 4 weeks | Reported to last about 3 days |
| Constipation | Can begin anytime in the first 16 weeks | May persist for an average of 47 days |
Other potential side effects of GLP-1s
Not every side effect comes directly from the GLP-1 medications themselves—some can happen simply because of the changes that come with losing weight or other things unrelated to the medication. Here are a few things people often ask about, plus what might help if you run into them:
Is muscle loss or loss of muscle tone a side effect of GLP-1s?
It’s not a direct effect of the medication, but losing weight quickly without enough protein or physical activity can lead to muscle loss.
What to do: Make sure you’re eating enough protein and try adding some resistance training to maintain your muscles.
What is “Ozempic face,” and is it caused by the drug?
Losing weight can lead to a loss of fat in the face, which can make your features look a bit sunken or hollow. This change is due to weight loss, not the medication directly.
What to do: Stay hydrated and talk to your provider about finding a more sustainable weight loss pace.
Why do I feel colder than usual on GLP-1s?
A lower body weight or reduced calorie intake can make it harder for your body to stay warm. This side effect is also due to weight loss, not the medication directly.
What to do: Stay active throughout the day and layer up if needed to help your body maintain warmth.
Is hair loss or thinning a side effect of GLP-1s?
Rapid weight loss can stress the body and affect hair growth. While the FDA is looking into it, hair loss hasn’t been directly tied to GLP-1 use.
What to do: Aim for a balanced diet with enough protein, iron, and other key nutrients that support hair health.
Do GLP-1s affect mood, anxiety, or depression?
Some people report emotional changes on GLP-1s, though the FDA has not found a connection between GLP-1s and depression. Weight loss or hormonal shifts may contribute.
What to do: Check in with your provider if you notice mood changes. For urgent help, contact the Suicide & Crisis Lifeline by calling 988.
Can GLP-1s cause insomnia?
Some people notice it’s harder to fall asleep or stay asleep, especially when their dose changes.
What to do: Eat lighter in the evening, avoid caffeine and screens before bed, and follow a consistent pre-sleep routine.
Have questions? Your healthcare provider or Noom Med clinician can help you determine what’s normal and what might need attention.
Do females experience different side effects of GLP-1s?
While the list of official side effects is the same for everyone, research shows that females are more likely to report certain side effects, such as nausea, vomiting, headaches, and dizziness, compared to males. Here are a few other things worth knowing about how GLP-1s might affect females:
- More regular periods with PCOS: Some studies suggest that people with PCOS might see their periods become more regular while using GLP-1s, thanks to weight loss and improved hormone balance.
- Cycle changes: Some people report irregular periods or spotting while using these medications. This may happen as weight loss affects hormone levels like estrogen.
- Fertility changes: Weight loss can sometimes improve ovulation, which might make pregnancy more likely. If you’re planning to conceive, you’ll need to stop your GLP-1 medication at least two months before trying.
- Birth control considerations: Because GLP-1s slow digestion, they might affect how your body absorbs oral birth control. Using a backup or non-pill method is often recommended, just to be safe.
If you notice changes in your cycle or are planning for pregnancy, check in with your healthcare provider. They can help you figure out what’s best for your health and your goals.
GLP-1s and injection site reactions
If you’re using a GLP-1 injectable like Ozempic®, Wegovy®, Mounjaro®, or Zepbound®, you might notice some mild skin reactions where you give your shot. Here’s what you might experience:
- Redness or swelling: After your injection, you might spot a small red or raised patch. This usually fades on its own within a day or two.
- Itching or irritation: Some people feel a slight itchiness after their shot. Try not to scratch since that can make it feel worse.
- Tenderness or bruising: A little soreness or a small bruise can happen, often from needle placement or how you give the shot.
Want to help prevent these? Try these quick tips, based on prescribing information for these medications:
- Rotate your injection sites each week among your belly, thigh, or upper arm.
- Clean the area with an alcohol swab and let it dry before injecting.
- Inject slowly and skip rubbing the area afterward to avoid extra irritation.
If the redness or pain continues or you notice anything unusual, like warmth or pus, reach out to your healthcare provider to get it checked out. But in most cases, these skin reactions are pretty manageable with just a few adjustments.
How to manage the most common GLP-1 side effects
Most GLP-1 side effects are manageable with a few strategies. Below are general recommendations from healthcare experts for some of the most commonly reported side effects tied to GLP-1 medications:
| Symptom | What can help |
|---|---|
| Nausea | Eat small, low-fat meals and avoid greasy or spicy foods to reduce nausea. |
| Vomiting | Stick to clear fluids and bland foods to soothe an upset stomach. |
| Diarrhea | Stay hydrated and choose low-fiber foods to support digestion while symptoms last. |
| Constipation | Add fiber slowly, drink more water, and move regularly to ease constipation. |
| Abdominal pain | Start with clear liquids and take a short break from solid foods to give your stomach a rest. |
| Dyspepsia/indigestion | Avoid trigger foods, reduce stress, and don’t eat too close to bedtime. Elevating your head at night may also help. |
| Headache | Stay hydrated, check blood sugar, and eat balanced meals. You can consider OTC pain relievers to help ease discomfort. |
| Fatigue | Staying well-hydrated, monitoring your blood sugar levels, and getting enough sleep can help support your energy. |
| Dizziness | Take your time when standing up and make sure you’re drinking enough water to help prevent lightheadedness. |
GLP-1s: What are the side effects of stopping a GLP-1?
Stopping a GLP-1 without a plan can bring back the issues you had before you took it. Any changes to your medication should be made under the guidance of your healthcare provider.
Here’s what to know:
- Hunger may return: GLP-1s work in part by reducing appetite. Once a medication is stopped, it’s common for hunger cues and food cravings to become more noticeable again.
- Some weight regain is likely: Without continued support from the medication, regaining some of the lost weight is possible.
- A gradual taper may help: In some cases, slowly reducing the dose under your provider’s guidance can ease the transition and give your body more time to adjust.
- Healthy habits make a difference: Building consistent routines around movement, nutrition, sleep, and stress management can help preserve your progress after stopping a GLP-1. Having tools for tracking, support, and accountability—like Noom—can also help.
Be sure to check in with your healthcare provider before making any changes to your treatment.
Severe side effects and warnings of GLP-1s
Serious side effects with GLP-1 medications are rare, but knowing what to watch for can help you catch problems early.
One important safety note: GLP-1s carry an FDA-boxed warning about the potential risk of thyroid C-cell tumors. While it’s not clear if this applies to humans, you shouldn’t take these medications if you or anyone in your family has a history of medullary thyroid cancer (MTC) or MEN 2. Be sure to tell your healthcare provider before you start.
Other rare but serious side effects to watch for and that require immediate medical attention include:
- Pancreatitis: Watch for severe stomach pain that persists and moves to your back. This can happen with or without nausea and vomiting.
- Gallbladder problems: Signs include pain in your upper belly, fever, yellowing of your skin or eyes, or pale-colored stools.
- Kidney issues: Dehydration from vomiting or diarrhea can put a strain on your kidneys. You might notice tiredness, swelling in your legs or feet, or urinating less often.
- Severe allergic reactions: Signs of an allergic reaction include swelling of your face, lips, tongue, or throat, trouble breathing, or a full-body rash.
- Low blood sugar (hypoglycemia): Hypoglycemia is more likely if you’re also taking insulin or diabetes medications. Symptoms include shakiness, sweating, dizziness, or confusion.
Most people won’t experience these issues, but it’s important to know what to watch for. If something feels off or you notice any of these symptoms, get medical help right away.
Who shouldn’t take GLP-1 medications?
GLP-1 medications can be helpful for many people, but they aren’t right for everyone. Certain preexisting health conditions or risks mean these medications aren’t safe for you.
You shouldn’t take GLP-1 medications if:
- You or a family member has ever had medullary thyroid cancer (MTC) or MEN 2 (a rare endocrine condition).
- You have a known allergy to the medication or any of its ingredients.
Your provider may advise extra caution or suggest another option if you:
- Have a history of pancreatitis.
- Struggle with severe digestive problems like gastroparesis since GLP-1s slow down digestion and could make symptoms worse.
GLP-1 medications also aren’t recommended if you’re pregnant, planning to become pregnant, or breastfeeding.
Before starting any GLP-1, be sure to go over your health history with your provider. They’ll help you decide if it’s a good fit for your goals and safety.
Long-term side effects and benefits of GLP-1 medications
GLP-1 medications are best known for helping with weight loss, but studies suggest their long-term impact can extend much further, especially when it comes to heart and kidney health.
GLP-1s may help protect the heart
A 2024 review highlights how these medications may do more than lower blood sugar or support weight loss. In major clinical trials, GLP-1s were linked to fewer strokes, heart attacks, and other serious heart issues, even for people taking other heart medications.
What makes this even more compelling is the possibility that GLP-1s may directly impact artery health. According to the review, these medications might help stabilize plaque buildup in the arteries, making it less likely to trigger dangerous events like heart attacks. That’s a powerful potential benefit that goes beyond the usual reasons people take these drugs.
Lower mortality and kidney benefits
Another 2024 study looked at people with a BMI over 30 (without diabetes) over five years. It found that those who used GLP-1 medications had a lower risk of all-cause mortality (death from any cause) during the study period and also had lower risks of heart failure, stroke, and kidney injury.
While this type of research can’t prove cause and effect, it does suggest that GLP-1s may support long-term health in more ways than one. Together with clinical trial data, it strengthens the idea that these medications could play a much bigger role in improving overall health.
Potential neurological and cognitive benefits
GLP-1s may also protect your brain. In a study, liraglutide slowed brain shrinkage and cognitive decline in early Alzheimer’s disease by 18%, and reduced atrophy in key memory areas by nearly 50% compared to placebo. In Parkinson’s research, a randomized trial of exenatide showed slowed motor deterioration after 48 weeks compared to placebo. Other data also links GLP-1 use to lower dementia risk in diabetics compared to sulfonylureas or insulin.
May improve liver health
GLP-1 medications may help improve liver conditions like fatty liver disease (NAFLD) and its more serious form, NASH. In a 2023 study, people taking 2.4 mg of semaglutide each week were nearly twice as likely to see NASH go away, without their liver scarring getting worse, compared to those on a placebo. They also had more improvement in liver scarring (called fibrosis). These benefits seem to go beyond just weight loss, suggesting GLP-1s may reduce inflammation in the liver directly.
They could help manage addiction
Could GLP-1 medications do more than curb appetite? Early research suggests they might also help reduce addictive behaviors. That’s because GLP-1 receptors aren’t just in the gut—they’re also in the brain areas linked to reward and cravings. Animal studies show that GLP-1 drugs can reduce the urge to use alcohol, cocaine, and opioids, and even lower the risk of relapse. One small study found that people with opioid use disorder had about 40% fewer cravings when taking liraglutide. There’s also data showing that people with diabetes on GLP-1s have lower rates of substance use disorders than those not taking them. It’s still in the early days, but the connection is promising—and it’s an exciting area for future research.
Understanding GLP-1 side effects
GLP-1 medications can be powerful tools for weight loss and diabetes management, but they come with side effects. Slow dose escalation is needed to help your body adjust, and it may take time to find the right medication and dose that works for you. Since different GLP-1s can affect people differently, it’s important to work with your provider to explore options and find the best fit for your needs. It’s a process, but with the right approach, these medications can make a significant impact on your health.
When it comes to GLP-1 therapy, the benefits often outweigh the risks. Significant weight loss can help improve health issues associated with a higher BMI. Beyond appetite control and weight loss, GLP-1s may also support heart, kidney, liver, and brain health—and potentially even reduce addictive behaviors. While more research is still needed, the potential benefits extend far beyond the scale. If you’re considering a GLP-1 or are already on one, staying informed and working closely with your healthcare team will help you get the most out of your treatment.
If you qualify for Noom Med, you’ll get personalized support from a licensed clinician who can answer questions, monitor your progress, prescribe medication if needed, and help you adjust your plan.
Note: Ozempic®, Rybelsus®, Mounjaro®, Victoza®, and Trulicity® are not FDA-approved for treating obesity or weight loss.
