Tirzepatide Side Effects: Hair Loss, Stomach Trouble, and What's Actually Serious

What are the most common side effects of tirzepatide?

Tirzepatide acts on two gut hormone receptors, called GIP and GLP-1. Together they slow how fast your stomach empties and quiet your appetite. Nearly every common side effect traces back to those two actions.

The figures below come from the adverse reactions table in Zepbound's FDA label. It pools two weight-loss trials. It compares the 5, 10 and 15 mg doses with placebo, a dummy shot.

Some stomach symptom showed up in 56% of people at every dose, against 30% on placebo. Most nausea, vomiting and diarrhea came during a dose increase and faded over time.

Few people quit over it. Even at the top dose, only 4.3% stopped because of stomach problems, against 0.5% on placebo.

Mounjaro's label comes from trials in people with type 2 diabetes, so its figures differ. There, nausea ran 12% to 18% by dose, against 4% on placebo. The trials enrolled different people, so the two labels don't rank the brands.

For Zepbound alone, see Zepbound side effects. To compare tirzepatide with semaglutide, using the one head-to-head trial, see GLP-1 side effects.

Does tirzepatide cause hair loss?

It can, though not by attacking your hair roots. Zepbound's label lists hair loss in 4% to 5% of people, against 1% on placebo. The label says these cases were linked to weight loss.

Women see it far more often. Among women in those trials, 7.1% reported hair loss on Zepbound, against 1.3% on placebo. Among men, it was 0.5%, against none on placebo. No one on Zepbound stopped treatment because of it.

The usual pattern is telogen effluvium, a temporary shedding all over the scalp. Fast weight loss pushes many hairs into a resting phase at the same time. A few months later, those hairs fall out together.

That delay is what catches people off guard. Shedding tends to start a few months after your fastest weight loss, not when you start the drug. For most people, hair grows back once weight settles. Mounjaro's label also lists hair loss among reports made after approval.

If perimenopause is already thinning your hair, the two can stack. Perimenopause hair loss explains that separate cause and what helps.

How long do tirzepatide side effects last, and how do you manage them?

Stomach symptoms are usually worst in the days after a dose increase. The label says most of them happened during dose increases and eased over time. A few habits cover most of what shows up.

• Follow the dose schedule. Increases come at least 4 weeks apart, to give your gut time to adjust. Rushing tends to backfire.
• Eat smaller, lower-fat meals. A large or fatty meal on a slowed stomach is a common nausea trigger.
• Drink enough fluids. This matters most during a stretch of vomiting or diarrhea, because losing fluid can harm your kidneys.
• Put protein first at each meal. It helps you feel full and protects muscle while you eat less. Our tirzepatide diet guide has the details.
• Use a new injection spot each week. The label says to rotate, even within the same area of your belly, thigh or upper arm.
• Notice your timing. You can take tirzepatide at any time of day, with or without food. Some people move their shot day once they see when nausea peaks.

What are the serious side effects, and does tirzepatide cause cancer?

A shorter list sits below the everyday stomach complaints. These problems are rarer. They are the reason for the label's warnings.

• Thyroid C-cell tumors. This is the boxed warning, the FDA's strongest kind. In rats, tirzepatide caused these tumors. It is not known whether it does in people. Don't take it if you or a relative had medullary thyroid cancer, or if you have MEN 2, a rare gene condition.
• Pancreatitis. This is swelling of the pancreas, the organ behind the stomach that helps digest food. It has been seen with tirzepatide and similar drugs, sometimes in a severe or fatal form. In Zepbound's weight-loss trials, confirmed cases were 0.2% on the drug and 0.2% on placebo.
• Gallbladder disease. Gallbladder inflammation affected 0.7% of people on Zepbound, against 0.2% on placebo. The label links these events to weight loss.
• Severe stomach reactions. These hit 1.7% to 3.1% of people by dose, against 1% on placebo. Tirzepatide isn't recommended if your stomach empties very slowly, a condition called severe gastroparesis.
• Kidney injury from dehydration. Long bouts of vomiting or diarrhea can drain enough fluid to harm the kidneys.
• Serious allergic reactions. These are rare and include swelling of the face or throat.
• Low blood sugar. The risk is highest if you also take insulin or a sulfonylurea, a type of diabetes pill.
• Eye changes with type 2 diabetes. A fast drop in blood sugar can briefly worsen diabetic eye disease, called retinopathy.
• Anesthesia. A slowed stomach raises the risk of breathing food into your lungs under sedation. Tell your care team before any procedure.

On the cancer question, the boxed warning is about one rare type, medullary thyroid cancer. The label says it is unknown whether tirzepatide causes it in people. The warning concerns C-cells, which are not the cells behind the common thyroid cancers.

For other cancers, the evidence so far is reassuring. A 2026 review in the Annals of Internal Medicine pooled 48 placebo-controlled trials of GLP-1 drugs and dual agonists like tirzepatide. It found they probably have little or no effect on pancreatic, thyroid, breast or kidney cancer. Those trials ran a few years at most, so longer studies continue.

Which side effects mean calling a doctor the same day?

Everyday nausea and bloating can wait for a routine message. The signs below can't. This list follows the Medication Guide that comes with Zepbound.

• Severe belly pain that won't go away, with or without nausea or vomiting. It can spread to your back. The guide says to stop the shot and call right away, since it can mean pancreatitis.
• Pain in your upper stomach, fever, yellow skin or eyes, or clay-colored stools. These can point to the gallbladder.
• Nausea, vomiting or diarrhea that won't go away. Losing that much fluid can lead to kidney problems.
• Swelling of the face, lips, tongue or throat, trouble breathing or swallowing, a severe rash, fainting, or a very fast heartbeat. These are signs of a serious allergic reaction. Get medical help right away.
• A lump or swelling in your neck, hoarseness, trouble swallowing, or shortness of breath. These can be signs of a thyroid tumor.
• Shakiness, sweating, confusion or a fast heartbeat if you also take insulin or a sulfonylurea. These can mean low blood sugar.
• Changes in your vision, if you have type 2 diabetes.

Are tirzepatide side effects different for women over 40?

The clearest difference on the label is hair loss, which women reported far more often than men. Beyond that, the menopause transition can blur the picture. Tiredness, broken sleep and stomach upset can come from either one.

A rough rule helps. Stomach symptoms that follow your dose increases are likely the drug. Tiredness or mood shifts that ignore your dosing, or arrive with hot flashes, more likely belong to perimenopause.

Birth control pills need a plan. Tirzepatide can make them work less well. Both labels advise switching to a non-pill method, or adding a barrier method like condoms. Do this for 4 weeks after you start, and for 4 weeks after each dose increase. Patches, rings, hormonal IUDs and implants are not affected.

What are tirzepatide's long-term side effects?

Tirzepatide has been sold as Mounjaro for type 2 diabetes since May 2022. That gives several years of safety data in that group. Weight-loss use under the Zepbound name is newer, since late 2023.

Part of the weight you lose is lean mass, which includes muscle. In a body-scan study inside the SURMOUNT-1 trial, about a quarter of the weight lost was lean mass. The share was about the same on placebo, but tirzepatide meant far more weight lost overall.

After 40, muscle is already harder to keep, so that deserves a plan. GLP-1s and muscle loss in perimenopause covers what protects it.

Bone has less research. Zepbound's label gives no bone density or fracture data. Weight loss in general can lower bone density, which matters more after menopause.

Stopping is the other long-term question. In the SURMOUNT-4 trial, everyone took tirzepatide for 36 weeks first. Those then switched to placebo regained 14% of their body weight over the next year. Those who stayed on it kept losing.

Is tirzepatide safe? Zepbound, Mounjaro and compounded versions

For most adults, yes, with the warnings above in mind. The common side effects are frequent but usually manageable. The serious ones are uncommon.

Zepbound and Mounjaro are the same drug with different FDA approvals. Zepbound is approved for weight management. It is also approved for moderate to severe sleep apnea in adults with obesity.

Mounjaro is approved for type 2 diabetes. Since August 2026, it is also approved to lower the risk of heart attack, stroke and heart-related death in adults with type 2 diabetes at high risk. Prescribing it for weight loss without diabetes is off-label, meaning a use the FDA has not approved. It is the same drug at the same doses, so the side effects carry over.

Compounded tirzepatide is a different case. A pharmacy mixes it, and the FDA does not review it for safety, quality or how well it works. The tirzepatide shortage ended in December 2024. The FDA now says compounded drugs should only be used when an approved drug can't meet a patient's needs.

By May 31, 2026, the FDA had received more than 730 reports of side effects with compounded tirzepatide. Some involved doses above the label, or dose increases faster than it allows. Many of the reported side effects matched those of the brand-name drug. Compounded tirzepatide covers the legal limits and prices.

Does a tirzepatide pill have different side effects than the shot?

There is no FDA-approved tirzepatide pill. Zepbound and Mounjaro are both weekly shots. Any tirzepatide tablet, troche, capsule or drop sold online is compounded.

Tirzepatide is a peptide, a small protein that stomach enzymes break down. No pill form of it has passed FDA review. So how much of an oral dose reaches your blood has not been shown.

Some telehealth programs sell one anyway. Henry Meds, for example, sells compounded tirzepatide only as a tablet. Tirzepatide pills and patches compares those options.

If you want an FDA-approved GLP-1 pill, Foundayo is a different Lilly drug, orforglipron, approved on April 1, 2026. Its own guide is Foundayo dosage.

What do real tirzepatide users say about side effects?

Forums and review sites repeat a few patterns. These are personal stories, not trial data, but they match the label well.

• The first weeks are the hardest. Nausea and a much smaller appetite lead most complaints.
• Hair shedding shows up later. Threads about it tend to come a few months after the biggest drop on the scale.
• Muscle worries come up often, mostly from people losing weight fast while eating little protein.
• Many bad reviews are about the company, not the drug. Billing, shipping and customer service draw more complaints than the medicine itself.

Tirzepatide reviews gathers what users report in more detail.

Where to get tirzepatide with support if a side effect isn't settling

If a symptom drags on past the first couple of months, programs differ most in what they include.

• [Mochi Health](/reviews/mochi-health/) prices by dose. It sells compounded tirzepatide as a weekly shot, and the price rises with your dose. A slower dose climb also keeps the bill lower.
• [Henry Meds](/reviews/henry-meds/) sells a tablet. Its compounded tirzepatide comes only as a tablet. That may suit you if shots are the problem, though tablets are not FDA-approved.
• [Fridays](/reviews/fridays/) includes a dietitian. One-on-one dietitian support and coaching help when appetite changes make meals hard.

For brand-name Zepbound, which follows the FDA label exactly, see Zepbound without insurance.