GLP-1 side effects and what's normal

The most common side effects are nausea, early fullness, constipation, mild stomach discomfort, and fatigue. These are usually mild and improve as your body adapts over several weeks. Small changes to meals, hydration, and timing can help manage most symptoms.

Nausea: Eat small, slow meals. Choose bland foods when queasy and avoid greasy or spicy options. Ginger tea or peppermints can help. Stop eating at early fullness.

Constipation: Build fiber intake gradually to 25-35 g/day (oats, beans, chia, psyllium). Drink 2--3 liters of water daily. A 10-20 minute walk after meals helps. If needed, try magnesium at night or an osmotic laxative (PEG 3350) per label directions.

If constipation is not improving: Add a daily fiber supplement such as psyllium (Metamucil), keep up fluids (about 8 to 12 cups, or 64 to 96 oz, a day; see "How much water should I drink, and do I need electrolytes?") and walking (even 10 minutes after meals), and try magnesium citrate or a fiber supplement. Avoid relying on laxatives long term. Do not increase your dose until your bowel movements are regular. If you have gone many days without a normal bowel movement despite these steps, or you are bloated and uncomfortable, message your care team. They may ask you to pause injections until it resolves and restart at a lower dose.

Gas, trapped gas, and burping: These are common because GLP-1 medications slow digestion. Eat smaller meals more slowly, skip carbonated drinks, and stay upright after eating. Heavy carbs, sugars, fast food, and coffee can make burping worse. Over-the-counter gas relief (such as Gas-X) can help. If pain above your belly button persists or gets worse, schedule a call with your provider.

Reflux or heartburn: Eat earlier, lighter dinners and stop eating 2-3 hours before lying down. Sip fluids between meals rather than during them. Limit common triggers — chocolate, peppermint, coffee, carbonation, alcohol, and very greasy or spicy food. Ginger (not peppermint) can settle the stomach. A short walk after meals helps.

If lifestyle changes and over-the-counter options are not enough, your care team can discuss other options. A prescription acid reducer (omeprazole) is one, usually taken every morning before eating for about 14 days, and Pepcid can be used for shorter-term relief. If you already take a reflux medicine, keep taking it as directed. Reflux sometimes gets worse after a dose increase, so ask your care team to review your dose if it keeps happening.

Contact your care team right away if reflux is severe, you have trouble swallowing, chest pain, or vomiting. Seek urgent care or call 911 if you vomit blood, have severe abdominal pain, or cannot keep fluids down.

Diarrhea or loose stools: Choose binding, gentle foods for a few days — rice, bananas, applesauce, toast, oatmeal, and baked chicken. Keep fat lower, favor cooked over raw vegetables, and limit sugar alcohols (sorbitol, xylitol) and very high-FODMAP foods. Magnesium supplements can also cause loose stools — if you started one for constipation, that may be the cause.

Fatigue and GI discomfort: Stay hydrated, prioritize protein at each meal, and consider adding electrolytes on active or hot days.

Side effects after a dose increase: Side effects tend to show up when your dose goes up, and they can appear at any step, even if earlier doses felt fine. Before assuming the dose is the cause, check the usual triggers: not eating enough protein before your injection, dehydration, undereating, overeating, and high-fat or heavily processed food. Fatty or fast food, sugary foods, carbonated drinks, and alcohol are common culprits.

If symptoms keep coming back after each dose, your dose may be too high for you right now. Do not increase your dose while side effects are ongoing. Only move up when your results level off and you are feeling well. A lower dose that works is better than a higher dose that makes you feel sick. Message your care team and they will review your dose. They may suggest going back to your previous dose and staying there longer, or ask whether splitting your weekly dose into two smaller injections is an option for you. Please do not change or split your dose on your own.

Nausea in particular: Eat a protein-rich breakfast before your injection, sip water or electrolytes through the day, and keep meals small. If you need more than diet changes, ask your care team about an anti-nausea medication (Zofran), which can be ordered through the patient portal.

Tiredness after your injection: Feeling tired on injection day and the day after is common, especially when you start or increase a dose. It usually eases over several days to a few weeks as your body adjusts.

• Take your shot in the evening so you can rest through it.
• Eat enough. Low protein, low calories, and low fluids are common causes of tiredness while you are eating less. A common target is around 100 g of protein a day. Eat small, balanced meals with protein and complex carbs.
• Plan lighter days after your shot and take short walks.
• If tiredness is severe, lasts more than a few days, goes on for several weeks even with good nutrition, or comes with dizziness or signs of low blood sugar, message your care team. They may check for other causes and review your dose. If you were already living with a fatigue condition, tell them if symptoms go beyond your usual baseline.
• You can also ask your care team whether an energy-support option is right for you.

Headaches and body aches: These can happen when you start or change dose. Drink enough water and electrolytes, eat regular meals with enough protein and fiber, and use an over-the-counter pain reliever such as Tylenol or Advil if needed, following the label. If headaches continue past 1 to 2 weeks despite these steps, or aches return with every dose, contact your care team. For dizziness, sleep, anxiety, and other non-stomach symptoms, see "Can my GLP-1 cause tiredness, headaches, dizziness, aches, anxiety, or trouble sleeping?"

Injection site reactions (redness, itching, small raised spots): Mild irritation is common, especially after a dose increase, and can last a few days to a few weeks. To reduce it:

• Rotate your injection site every week (thigh, abdomen, back of the upper arm), and avoid injecting near your belly button.
• Let the medication warm to room temperature for 15 to 30 minutes before injecting.
• Take an oral antihistamine on injection day, and apply an over-the-counter antihistamine cream to the site afterward.
• If you notice reactions only with certain vials, ask your care team about an additive-free formulation, since B vitamin additives can add to skin sensitivity for some people.

Contact your care team if the rash is getting worse or spreading. If a rash, hives, or itching spreads beyond the injection site or across your body, hold your next injection and contact your care team right away, since it could be an allergic reaction. Swelling of the face, lips, or throat, or trouble breathing, is an emergency: call 911.

When to contact your provider: Reach out if nausea or vomiting lasts more than 24 hours, you can't keep fluids down, constipation lasts more than 3--4 days despite taking steps above, or side effects worsen after a dose increase.

Hold your next injection if you are still having significant symptoms. Do not inject while you have active vomiting, ongoing diarrhea, or other significant stomach symptoms. Wait until you are feeling back to normal and hydrated. Then message your care team before your next dose, since they will often recommend restarting at a lower dose so your body can adjust more gradually.

• Vomiting for several days, or vomiting you cannot control: message your care team the same day. Seek urgent care if you cannot keep fluids down or feel dizzy or weak.
• Symptoms that are longer or different from your usual pattern (for example, flu-like symptoms lasting several days after a shot that usually bothers you for one day): ask your care team to review it.
• A rash, hives, or itching that spreads beyond the injection site or across your body: hold your next injection and contact your care team. See "Injection site reactions" above.
• If you are recovering from a stomach virus and your symptoms are lingering, your care team may suggest pausing until you feel completely normal, then restarting, so it is clearer whether the virus or the medication is causing symptoms.

Warning signs --- seek urgent care: Severe or persistent abdominal pain, repeated vomiting, signs of dehydration, black or bloody stools, yellowing skin or eyes, swelling of face or throat, trouble breathing, chest pain, confusion, or severe weakness. If you think it's an emergency, call 911.