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What About the Serious Side Effects of Semaglutide and Tirzepatide?

Medically reviewed by our physician · Updated September 19, 2026 · Washington Trim Clinic, Bellevue, WA
The short answer

Stomach side effects are common and usually mild or moderate. The frightening ones you see in lawsuit ads are rare. The real danger is having a side effect and nobody to call. At our Bellevue clinic you start on a low dose, and a team that knows you can stop or change the plan.

What is true

  • These are real medications with real risks. Nobody should tell you otherwise.
  • There is a thyroid tumor warning, based on animal studies. People with a personal or family history of medullary thyroid cancer or MEN2 should not take these drugs.
  • Gallbladder problems happened in about 2 in 100 people in the brand-name trials.
  • These drugs are not for use if you are pregnant, trying to become pregnant, or breastfeeding.
  • If you have type 2 diabetes: diabetes alone does not rule you out, but people who take insulin or insulin-related medication are not candidates for our program. GLP-1 medications taken with insulin or some other diabetes drugs can cause low blood sugar. Tell us every medication you take, and our physician reviews them.

What we do about it

  • Our physician reviews your health history before anything is prescribed.
  • You start on a low dose. It goes up slowly, and only if you are doing well.
  • A rash, or nausea that does not settle? We stop or change the plan.
  • Most side effects can be managed. See what usually helps, then ask us what is right for you.
  • Feel unwell? Call or text us. Our team replies the same business day, and the doctor can change your dose. To call: (425) 552-3755.
  • Strong stomach pain that does not go away, or trouble breathing, is an emergency. Call 911, at any hour.

What usually helps, and why you should ask us first

General information only, not medical advice. This section describes what commonly helps people in general. It is not advice for you, and reading it does not make you our patient. What is right for you depends on your health history, your other medications and your dose. If you are our patient, call or text us before you change anything, and our team and physician will advise you personally. If you are not our patient, speak with the doctor or clinic that prescribed your medication. In an emergency, call 911.

Most side effects are manageable, and there is usually something that helps. These are the general steps described in a published expert guide. Your own plan comes from us.

Nausea

Smaller meals, eaten slowly, and less fried, fatty or very sweet food often help. If it does not settle, our physician can hold your dose or go back one step.

Vomiting

Small sips of fluid, often. Contact us the same day. If you cannot keep fluids down, get medical care right away.

Constipation

More water, more fiber added slowly, and a daily walk help most people. For some of our patients, changing from semaglutide to tirzepatide has helped (in a trial comparing the brand-name drugs, fewer people stopped tirzepatide because of stomach side effects). Our physician decides if that is right for you.

Diarrhea

Plenty of fluids, and less fatty food for a few days. It usually passes in a few days. If it does not, contact us.

Heartburn and bloating

Smaller meals, an earlier last meal, and fewer fizzy drinks often help. Tell us if it continues.

Feeling tired

This often means too little food or water. Reaching your calorie, protein and water targets usually helps.

Redness where you inject

Change the injection place each week. A rash that spreads is different: stop and call us.

Hair shedding

Some people, women more often than men, notice more hair shedding a few months after they start. In the brand-name trials, about 5 to 7 in 100 people on Zepbound (tirzepatide) and 3 in 100 on Wegovy (semaglutide) reported it, compared with about 1 in 100 on placebo (Zepbound label, Wegovy label). A 2026 research review links it mainly to losing weight quickly, not to damage to the hair root, and hair usually grows back within 3 to 6 months after weight becomes stable. Enough protein and a slower pace of weight loss help. Tell us if you notice it, and we will look at your protein target and your dose. More: hair loss on GLP-1 medication and tirzepatide and hair loss.

The most useful step is to tell us. Two people with the same side effect can need different answers. Our team replies the same business day, and our physician can hold, lower, pause or change your medication. Strong stomach pain that does not go away, vomiting that will not stop, yellow skin or eyes, swelling of the face or throat, or trouble breathing are emergencies. Call 911.

The numbers, common and rare

People reporting each effect in the clinical trials of brand-name Wegovy (semaglutide), from the FDA prescribing information. Blue = medication. Grey = placebo (an injection with no medication).

Nausea
44%
16%
Diarrhea
30%
16%
Vomiting
24%
6%
Constipation
24%
11%

In the trials of brand-name Zepbound (tirzepatide), nausea was reported by 25% to 29% of people depending on dose, compared with 8% on placebo (FDA prescribing information). For both drugs most effects were mild and came when the dose went up. About 5 to 7 in 100 people stopped because of side effects.

In our own clinic: about 2 to 3 in 100 of our patients developed a skin rash, and we stopped their medication. About 1 in 100 stopped because of nausea. These are our own records, not a study.

Common questions

What is the most common side effect of semaglutide and tirzepatide?

Nausea. In the brand-name trials, 44% of people on Wegovy (semaglutide) and 25% to 29% on Zepbound (tirzepatide) reported nausea, compared with 16% and 8% on placebo. It was usually mild and tended to appear when the dose went up.

What helps with constipation on semaglutide or tirzepatide?

In general, more water, more fiber added slowly, and a daily walk help most people. For some of our patients, changing from semaglutide to tirzepatide has helped. This is general information, not personal medical advice. If you are our patient, contact us and our physician will advise you. If not, ask the clinic that prescribed your medication.

Do semaglutide and tirzepatide cause hair loss?

Some people notice more hair shedding a few months after starting, women more often than men. In the brand-name trials, about 5 to 7 in 100 people on Zepbound (tirzepatide) and 3 in 100 on Wegovy (semaglutide) reported hair loss, compared with about 1 in 100 on placebo. Research links it mainly to losing weight quickly. It usually grows back within 3 to 6 months after weight becomes stable. Enough protein and a slower pace of weight loss help. Ask your own clinic for personal advice.

Do semaglutide and tirzepatide cause stomach paralysis?

Serious stomach and bowel problems are reported but rare. Strong stomach pain that does not go away is an emergency, and you should call 911.

Do semaglutide or tirzepatide cause suicidal thoughts?

The FDA reviewed trial and real-world data and found no increased risk. In January 2026 it asked for that warning to be removed from the labels.

Can I take semaglutide or tirzepatide if I have type 2 diabetes?

Type 2 diabetes alone does not rule you out. People who take insulin or insulin-related medication are not candidates for our program. Our physician reviews every medication you take before anything is prescribed.

What happens if I get side effects at Washington Trim Clinic?

Call or text us. Our team replies the same business day, and our physician can lower the dose, pause, or stop the medication.

More honest answers

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Sources

Compounded medication is made for one patient, so it does not go through the FDA approval process. How we choose and check our pharmacies. Trial figures on this page describe brand-name products and are not a promise of results. Individual results vary. This page is general information, not medical advice.