Semaglutide Side Effects: What to Expect and When They Ease

Most people who take semaglutide get stomach side effects, and most of those fade. In the adult weight-loss trials behind the label of the FDA-approved semaglutide product for weight management, 73% of people on the 2.4 mg weekly dose reported a digestive side effect, compared with 47% on placebo. Nausea was the most common at 44%. These effects cluster in the first four to five months, while the dose is stepped up, and a typical bout of nausea lasted about 8 days. About 7% of people stopped treatment because of side effects. Rare but serious risks, including pancreatitis, gallbladder disease, and a boxed warning about thyroid tumors seen in rodents, need to be understood before starting.

What semaglutide is and why it causes side effects

Semaglutide is a GLP-1 receptor agonist: a lab-made version of glucagon-like peptide-1, a hormone your gut releases after you eat. In the United States it is sold as an FDA-approved semaglutide product for type 2 diabetes (a weekly injection and, under the January 2026 label, also a daily tablet), as a separate oral semaglutide tablet for type 2 diabetes, and as an FDA-approved semaglutide product for weight management (a weekly injection or a daily tablet for weight reduction and for lowering cardiovascular risk). This guide leans mostly on the prescribing information for the weight-management semaglutide product, because it covers the doses used for weight management and reports side effects in the most detail.

The same actions that make the drug work also explain most of its side effects. According to the prescribing information, semaglutide lowers calorie intake, most likely by acting on appetite, and GLP-1 receptors are present in several brain areas that regulate appetite. It also delays gastric emptying, meaning food leaves your stomach more slowly. A stomach that empties slowly, combined with a brain signal that says "you have had enough," is a reasonable explanation for nausea, fullness, belching, and reflux. If you want the fuller picture of the mechanism, see how GLP-1 weight loss injections work.

One more fact shapes the whole timeline: semaglutide has an elimination half-life of about 1 week. That is why it can be injected once weekly. It also means the drug builds up gradually over the first several weeks at each dose, and that it stays in your circulation for about 5 to 7 weeks after the last dose. Side effects neither start nor stop overnight.

Regulatory status as of September 2026

As of September 2026, semaglutide is FDA approved. The current label for the weight-management semaglutide product (revised June 2026) lists three uses for the injection: reducing the risk of major cardiovascular events in adults with established cardiovascular disease and either obesity or overweight; reducing excess body weight and maintaining the reduction in adults and children 12 and older with obesity, and in adults with overweight plus at least one weight-related condition; and treating a form of fatty liver disease called MASH with moderate to advanced fibrosis, under accelerated approval. The weight-management semaglutide tablets are approved for the cardiovascular and weight indications in adults. Every semaglutide product carries a boxed warning, the FDA's strongest, about thyroid C-cell tumors.

Compounded semaglutide is a different matter. Compounded drugs are not FDA approved, and the FDA does not review them for safety, effectiveness, or quality before they are sold. The FDA reports that as of May 31, 2026, it had received 990 adverse event reports involving compounded semaglutide, and that some reports requiring hospitalization may have been related to dosing errors, including patients measuring and self-administering incorrect doses and health care professionals miscalculating doses. The agency has also raised concerns about salt forms (semaglutide sodium and semaglutide acetate), which it considers different active ingredients from the one in the approved drugs. On April 30, 2026, the FDA proposed excluding semaglutide from the list of bulk substances that large outsourcing compounders may use; that proposal had not been reported as final when this guide was written. The side effect numbers in this guide come from trials of the approved products and may not apply to compounded versions.

Why the dose starts low and climbs slowly

Nobody starts semaglutide at the full dose. The weight-management semaglutide label sets a starting dose of 0.25 mg once weekly and instructs prescribers to follow a stepwise escalation, stating the reason plainly: to reduce the risk of gastrointestinal adverse reactions. The starting dose is not the treatment dose. It exists to let your body adapt.

Two details in the label matter for side effects. First, if you do not tolerate a dose during escalation, the label tells prescribers to consider delaying the next step by 4 weeks. Slowing down is built into the official schedule and is not a failure. Second, for weight reduction, the maintenance dose can be either 2.4 mg or 1.7 mg, chosen on response and tolerability. The decision about which dose you stay on belongs to you and your prescriber.

The current label also includes a higher option for adults: for people who have tolerated 2.4 mg for at least 4 weeks and for whom more weight reduction is clinically indicated, the dose may be raised to a maximum of 7.2 mg once weekly, using the higher-dose (7.2 mg) semaglutide product. The tablet form has its own ladder: 1.5 mg daily for 30 days, then 4 mg, then 9 mg, each for 30 days, reaching 25 mg daily from day 91.

Each step up is a fresh exposure to a higher drug level, and because of the one-week half-life, blood levels keep rising for several weeks after each increase. This is why side effects often flare for a week or two after a dose increase and then settle, and why the first 16 to 20 weeks are the bumpiest stretch.

How common each side effect is

The most reliable frequencies come from the pooled adult weight-management trials summarized in the prescribing information for the weight-management semaglutide product: three randomized, double-blind, placebo-controlled trials in which 2,116 adults took 2.4 mg weekly for up to 68 weeks and 1,261 took placebo. The table shows most of the side effects reported by at least 2% of people on semaglutide and more often than on placebo (the label's table also lists gastritis, gastroenteritis, and low blood sugar in people with type 2 diabetes).

Read the placebo column too

Notice that 16% of people on placebo reported nausea and 16% reported diarrhea. Everyone in these trials was also on a reduced-calorie diet and being asked about symptoms at every visit. The fair way to read the table is the gap between the columns: semaglutide added roughly 28 percentage points of nausea, 18 points of vomiting, 14 points of diarrhea, and 13 points of constipation on top of what people reported anyway.

How severe are they

A pooled analysis of the STEP 1 to 3 trials (2,117 people on semaglutide 2.4 mg, 1,262 on placebo), published in Diabetes, Obesity and Metabolism in 2022, found that 99.5% of gastrointestinal events on semaglutide were non-serious and 98.1% were mild to moderate. The label puts the rate of severe gastrointestinal reactions at 4.1% with the injection versus 0.9% with placebo. So about 1 in 25 people has a digestive reaction rated severe. One caution about this analysis: it was funded by the manufacturer, as were the trials themselves.

How many people stop because of side effects

In the pooled label data, 6.8% of people on semaglutide 2.4 mg and 3.2% on placebo permanently stopped treatment because of side effects. Nausea (1.8%), vomiting (1.2%), and diarrhea (0.7%) were the leading reasons. In STEP 1 alone (1,961 adults, 68 weeks, published in the New England Journal of Medicine in 2021), 4.5% stopped for gastrointestinal reasons versus 0.8% on placebo. The pooled analysis found that most of these discontinuations happened during dose escalation.

The picture was less rosy in the much larger and longer SELECT trial: 17,604 adults with cardiovascular disease, followed for an average of about 40 months. There, 16.6% of people on semaglutide stopped the drug because of adverse events, compared with 8.2% on placebo. SELECT participants were older (45 and up) and the trial ran far longer, so the two figures are not directly comparable, but they show that tolerance in a tightly run 68-week trial is a best case.

Lower doses cause fewer side effects

Side effects rise with dose. In the placebo-controlled diabetes trials summarized in the label for the FDA-approved semaglutide product for type 2 diabetes, nausea was reported by 15.8% of people on 0.5 mg and 20.3% on 1 mg, versus 6.1% on placebo, and overall digestive side effects by 32.7% and 36.4% versus 15.3%. Those rates are about half, or less, of what is seen at 2.4 mg. If you are taking semaglutide for type 2 diabetes at those doses, the numbers in the large table above overstate what you should expect.

The 7.2 mg dose and altered skin sensation

At the newer 7.2 mg dose, the label reports results from two 72-week trials in which 1,311 adults with obesity were assigned to 7.2 mg, 304 to 2.4 mg, and 303 to placebo. Nausea (39% versus 35%) and vomiting (22% versus 16%) were somewhat more common than at 2.4 mg, and the share who quit over side effects was the same, 5% in each semaglutide group.

The standout difference was dysesthesia: altered skin sensations such as tingling, burning, sensitive skin, or pain from light touch. It was reported by 22% of people on 7.2 mg, 6% on 2.4 mg, and 0.3% on placebo. The label says its frequency rises with dose and blood level. Most people recovered, faster when the dose was reduced or paused, but 18% of those affected had not reported recovery by the end of the trial. With the 25 mg tablet, 5% reported it versus none on placebo. This is a real, dose-related effect that few people have heard of, and it is worth reporting to your prescriber if it appears.

The timeline: what to expect and when it eases

Trials report side effects as "ever happened during 68 weeks," which makes them sound constant. They are not. The pooled STEP analysis tracked how many people had each symptom at any given time, and how long individual episodes lasted. That gives a realistic calendar. Your own course may differ: these are averages from trial participants, and delays in escalation shift everything later.

Weeks 1 to 4: the starting dose

The 0.25 mg dose is low, but the drug accumulates across the first month, so side effects can appear after the first injection or build in week 3 or 4. Common early reports are mild nausea, feeling full quickly, belching, and a change in bowel habits in either direction. Many people feel little at this stage. Feeling nothing at 0.25 mg does not predict how the higher doses will feel, and it does not mean the medication is failing.

Weeks 5 to 16: escalation

Each four-week step roughly doubles the dose at first (0.25 to 0.5 to 1 mg), then rises more gently (1.7, then 2.4 mg). A common pattern is a flare of nausea or loose stools in the first week or two after each increase, followed by calmer weeks. Both the weight-management and type 2 diabetes semaglutide labels state that most reports of digestive side effects occurred during dose escalation, and the label notes that kidney problems related to dehydration also occurred more often during titration. This is the stretch in which staying hydrated and reporting persistent vomiting matter most.

Weeks 17 to 20: reaching the full dose

On the standard schedule you reach 2.4 mg at week 17, and blood levels take several more weeks to plateau. That is consistent with the pooled STEP finding that the proportion of people experiencing nausea, vomiting, or diarrhea at any given time peaked around week 20. If the month after reaching the full dose feels like the hardest one, that matches the trial data.

After week 20: maintenance

From about the fifth month on, the proportion of people with active nausea, vomiting, or diarrhea fell steadily in the STEP trials. Side effects do not vanish, though. In STEP 4, where everyone took semaglutide for 20 weeks and was then randomly assigned to continue or switch to placebo, 41.9% of those who continued reported a new digestive event during the following 48 weeks, compared with 26.1% of those switched to placebo. In the two-year STEP 5 trial (304 adults), 82.2% of people on semaglutide reported a digestive side effect at some point over 104 weeks, versus 53.9% on placebo, and the investigators again described most events as mild to moderate and transient.

How long a single episode lasts

This is the most reassuring number in the literature. In the pooled STEP 1 to 3 analysis, the median duration of an individual episode on semaglutide was 8 days for nausea, 3 days for diarrhea, and 2 days for vomiting. Median means half of episodes were shorter and half were longer. These are bouts, and most people have stretches of feeling normal between them.

Constipation is the slow one

Constipation behaved differently. Its median duration was 47 days on semaglutide (35 days on placebo), and its prevalence leveled off around week 10 and stayed there instead of fading. If constipation appears, expect it to need ongoing management with fluids, fiber, and movement, and tell your prescriber if it becomes severe. Severe constipation, fecal impaction, and intestinal blockage appear in the label's postmarketing reports.

If you miss doses and restart

Tolerance fades when the drug is stopped. The current label says that if 2 or more consecutive weekly injections are missed, dose escalation should be reinitiated at a lower dose, to reduce the risk of digestive side effects. If you have been off semaglutide for a few weeks, talk with your prescriber before taking your previous dose. For what else changes when treatment stops, see what happens when you stop taking semaglutide.

Do side effects cause the weight loss

A common belief is that semaglutide works by making you too queasy to eat. The pooled STEP analysis tested this. People with digestive side effects lost slightly more weight than people without (in STEP 1, 17.3% versus 15.7%), but a formal mediation analysis found that less than 1 percentage point of the drug's extra weight loss over placebo was explained by those side effects. People who never felt sick still lost nearly as much. Suffering is not a sign that the drug is working, and the absence of nausea is not a sign that it is failing.

What helps with stomach side effects

There are no large randomized trials of diets or remedies for GLP-1 side effects. The best available guidance is expert consensus, which is a weaker tier of evidence than the trial data above. A multidisciplinary panel published recommendations in the Journal of Clinical Medicine in 2022. Their suggestions are low risk and widely used:

• Eating habits: eat slowly, eat smaller portions, eat more often instead of having large meals, stop when you feel full, avoid lying down after a meal, and eat without distractions so you notice fullness.
• Nausea: avoid strong smells; bland or soothing foods such as crackers, apples, mint, or ginger may help.
• Vomiting: keep up fluids in small, frequent sips and keep meals small. Vomiting that prevents you from keeping fluids down needs medical attention because of the dehydration and kidney risk described below.
• Diarrhea: drink generously; temporarily cut back on dairy, coffee, alcohol, soft drinks, very hot or very cold foods, and high-fiber foods until it settles.
• Constipation: adequate fiber, generous water intake, and regular physical activity.

For prescribers, the same panel recommends extending the escalation phase when side effects occur: staying 2 to 4 more weeks at the previous dose or pausing temporarily. This mirrors the label's advice to consider delaying escalation by 4 weeks. Whether to slow down, step back, or use an anti-nausea medication is a decision for your prescriber. Do not adjust the dose on your own.

Serious risks

The side effects above are common and usually manageable. The ones below are uncommon or rare, but they are the reason semaglutide requires a prescription and follow-up.

Boxed warning: thyroid C-cell tumors

In mice and rats, semaglutide caused thyroid C-cell tumors, including cancers, in a dose-dependent and duration-dependent way at blood levels similar to those in people. This is animal evidence. The label states that it is unknown whether semaglutide causes these tumors, including medullary thyroid carcinoma (MTC), in humans. Because of the uncertainty, semaglutide is contraindicated in anyone with a personal or family history of MTC or with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2), an inherited condition that predisposes to MTC.

Human data are observational and conflicting. A French case-control study in Diabetes Care (2023), with 2,562 thyroid cancer cases and 45,184 controls, all people with type 2 diabetes, found that 1 to 3 years of GLP-1 drug use was associated with a higher risk of all thyroid cancer (adjusted hazard ratio 1.58) and of medullary thyroid cancer (1.78). A larger Scandinavian cohort study in the BMJ (2024) compared 145,410 GLP-1 users with 291,667 users of another diabetes drug class over an average of 3.9 years and found no increased risk of thyroid cancer (hazard ratio 0.93, 95% confidence interval 0.66 to 1.31). Its estimate for medullary cancer specifically was too imprecise to settle the question (1.19, interval 0.37 to 3.86). Neither study type can prove or rule out causation. In the Scandinavian study thyroid cancer was rare whichever drug people took: about 1.3 to 1.5 cases per 10,000 person-years.

The label advises against routine calcitonin blood tests or thyroid ultrasound for screening, because they are of uncertain value and can lead to unnecessary procedures. It does advise reporting symptoms: a lump in the neck, trouble swallowing, shortness of breath, or persistent hoarseness.

Pancreatitis

Acute pancreatitis, including fatal cases, has been reported with GLP-1 drugs. In the adult weight-management trials it was confirmed in 4 people on semaglutide (0.2 cases per 100 patient-years) and 1 on placebo (less than 0.1). The warning sign is severe abdominal pain that does not go away, sometimes spreading to the back, with or without vomiting. The label instructs that semaglutide be discontinued if pancreatitis is suspected. Blood levels of the pancreatic enzymes lipase and amylase rise on average with semaglutide (lipase by 39%), and the label says the significance of that rise on its own, without symptoms, is unknown.

Gallbladder disease

In the adult weight-reduction trials, gallstones were reported by 1.6% of people on the injection versus 0.7% on placebo, and gallbladder inflammation (cholecystitis) by 0.6% versus 0.2%. Rates were higher in adolescents (gallstones in 3.8% versus 0%). Rapid weight loss itself raises gallstone risk, but the label notes that gallbladder disease was more common on semaglutide even after accounting for the amount of weight lost. Symptoms include pain in the upper right or middle abdomen, fever, yellowing of the skin or eyes, and clay-colored stools.

Dehydration and kidney injury

The label carries a warning titled acute kidney injury due to volume depletion. There have been postmarketing reports of acute kidney injury, some requiring dialysis, mostly in people who had become dehydrated from nausea, vomiting, or diarrhea. In the weight-reduction trials, acute kidney injury occurred in 7 people on semaglutide (0.4 per 100 patient-years) versus 4 on placebo (0.2), more often during dose titration and in people with existing kidney impairment. The practical message: persistent vomiting or diarrhea is a kidney issue as well as a comfort issue.

Severe stomach problems, gastroparesis, and bowel obstruction

The label warns of severe gastrointestinal reactions and says semaglutide is not recommended in people with severe gastroparesis, a condition in which the stomach empties very slowly. Postmarketing reports include ileus (a bowel that stops moving), intestinal obstruction, and severe constipation with fecal impaction. Because these come from voluntary reports, their true frequency cannot be calculated.

The main published estimate comes from a research letter in JAMA (2023) that used a US insurance claims database. Compared with people taking bupropion-naltrexone, another weight-loss drug, people taking semaglutide or liraglutide had higher rates of gastroparesis (adjusted hazard ratio 3.67), bowel obstruction (4.22), and pancreatitis (9.09). For semaglutide the gastroparesis rate was 9.1 per 1,000 person-years, based on just 4 cases. The limits are serious: only 613 semaglutide users were included, event counts were small (the confidence interval for pancreatitis ran from 1.25 to 66), body mass index was unavailable, and it is an observational study. Treat it as a signal that these events are uncommon but real, not as a precise risk.

Aspiration during anesthesia or deep sedation

Because semaglutide slows stomach emptying, food can remain in the stomach even after a normal pre-procedure fast. The label describes rare postmarketing reports of pulmonary aspiration (stomach contents entering the lungs) during general anesthesia or deep sedation in people taking GLP-1 drugs, and says the data are insufficient to recommend a specific fix such as a longer fast or pausing the drug. It tells patients to inform their healthcare providers about semaglutide before any planned surgery or procedure.

Guidance released in October 2024 by five medical societies, including the American Society of Anesthesiologists and the American Gastroenterological Association, says most patients can continue GLP-1 drugs before elective surgery. It identifies people at higher risk: those in the dose-escalation phase, those on higher doses, and those with active nausea, vomiting, or abdominal pain. For them it suggests measures such as a liquid diet for 24 hours beforehand, a bedside ultrasound of the stomach, or postponing elective procedures until symptoms settle. Tell your surgeon, your anesthesiologist, and whoever is performing your colonoscopy or endoscopy that you take semaglutide, and let them decide the plan with your prescriber.

Low blood sugar

On its own, semaglutide stimulates insulin only when blood sugar is elevated, so low blood sugar (hypoglycemia) is mainly a concern for people with type 2 diabetes who also take insulin or a sulfonylurea. In the weight-management trial in adults with type 2 diabetes, clinically significant hypoglycemia (below 54 mg/dL) occurred in 6.2% on semaglutide versus 2.5% on placebo. The label advises prescribers to consider lowering the dose of insulin or the sulfonylurea when starting semaglutide. It also notes more serious hypoglycemia in people with prior bariatric surgery in the SELECT trial (2 of 87 on semaglutide versus 0 of 97 on placebo).

Eyes: diabetic retinopathy and NAION

In a 2-year trial of lower-dose semaglutide in people with type 2 diabetes and high cardiovascular risk, complications of diabetic retinopathy (diabetes-related damage to the retina) occurred in 3% on semaglutide versus 1.8% on placebo. The increase was concentrated in people who already had retinopathy (8.2% versus 5.2%). Rapid improvement in blood sugar is known to temporarily worsen retinopathy. The label advises monitoring people with a history of diabetic retinopathy.

A separate issue is non-arteritic anterior ischemic optic neuropathy (NAION), a rare loss of blood flow to the optic nerve that causes sudden, painless vision loss in one eye. A 2024 study in JAMA Ophthalmology from a single neuro-ophthalmology center found a higher rate of NAION in people prescribed semaglutide (hazard ratio 4.28 in those with diabetes, 7.64 in those with overweight or obesity), but it drew from a specialty referral population and cannot show causation. In June 2025 the European Medicines Agency's safety committee reviewed all available data and concluded that NAION is a very rare side effect of semaglutide, affecting up to 1 in 10,000 people, with large studies in adults with type 2 diabetes suggesting roughly a two-fold increase in risk, or about one extra case per 10,000 person-years of treatment. The June 2026 US label for the weight-management semaglutide product does not list NAION. Sudden vision loss or rapidly worsening eyesight warrants immediate medical attention regardless.

Heart rate

Semaglutide raises resting heart rate by an average of 1 to 4 beats per minute. More people on semaglutide than placebo had an increase of 20 beats per minute or more at some visit (26% versus 16%). The label advises reporting palpitations or a racing heartbeat at rest, and discontinuation if a sustained increase in resting heart rate occurs. For context, in SELECT the same drug reduced heart attacks, strokes, and cardiovascular deaths by 20% (6.5% versus 8.0% had an event) in people with existing cardiovascular disease.

Allergic reactions

Serious allergic reactions, including anaphylaxis and angioedema (swelling of the face, lips, tongue, or throat), have been reported. A prior serious hypersensitivity reaction to semaglutide or its ingredients is a contraindication. Mild injection site reactions such as redness or itching occurred in 1.4% of people versus 1% on placebo.

Mood and suicidal thoughts: a warning that was removed

When the weight-management semaglutide product was approved, its label included a warning about suicidal behavior and ideation. On January 13, 2026, the FDA announced that it had asked manufacturers to remove that warning from the weight-management semaglutide, liraglutide, and tirzepatide products. Its review covered 91 placebo-controlled trials with 107,910 participants and found no increased risk of suicidal thoughts or behavior with GLP-1 drugs, and an FDA study of insurance data covering more than 2.2 million people found no increase in intentional self-harm compared with users of another diabetes drug class. The current weight-management semaglutide label no longer contains the warning. A large electronic health record study in Nature Medicine (2024) had pointed the same direction. None of this means mood changes should be ignored: tell your prescriber about new or worsening depression, and in the US the 988 Suicide and Crisis Lifeline is available at any hour.

Other signals in the label

• Low blood pressure and fainting: hypotension in 1.3% versus 0.4% on placebo, and fainting in 0.8% versus 0.2%, more often in people taking blood pressure medication. Doses of those medications sometimes need review as weight falls.
• Hip and pelvis fractures: in SELECT, more fractures of the hip and pelvis occurred on semaglutide among women (1% versus 0.2%) and people 75 and older (2.4% versus 0.6%).
• Kidney stones: reported by 1.2% versus 0.8% on placebo in SELECT.
• Appendicitis: 0.5% versus 0.2% in the weight-reduction trials.
• Altered taste: 1.7% versus 0.5%.

Muscle loss, hair loss, and other effects of losing weight

Some effects blamed on semaglutide are largely consequences of losing a lot of weight, by any method.

Muscle and lean mass

The only direct body composition data from the main weight-loss trials come from a substudy of STEP 1 in which 140 people (95 on semaglutide) had DEXA scans, an X-ray method that separates fat from lean tissue. Over 68 weeks the semaglutide group lost 15.0% of body weight. Total fat mass fell 19.3%, visceral (deep abdominal) fat fell 27.4%, and total lean body mass fell 9.7%. Because fat fell proportionally more, lean mass as a share of body weight rose by 3.0 percentage points.

Two cautions apply. "Lean mass" on a DEXA scan includes water and organ tissue as well as muscle, so a 9.7% drop is not a 9.7% loss of muscle. And the substudy was small, exploratory, reported as a conference abstract, and did not measure strength or physical function. Still, a meaningful loss of lean tissue is real, and it matters most for older adults, which fits uneasily with the fracture signal in SELECT. Resistance training and adequate protein are the standard recommendations for preserving muscle during any weight loss, though no large randomized trial has yet tested them specifically in people taking semaglutide. If your efforts in the gym are not showing up on the scale, why you might be working out but not losing fat covers the basics.

Hair loss

Hair loss was reported by 3.3% of adults on 2.4 mg versus 1% on placebo (4% of women, 0.9% of men), and by 5.8% on 7.2 mg. The label states that hair loss was associated with weight reduction, which points to the weight loss itself as at least part of the cause. The trials did not follow hair regrowth, so good data on how long it lasts in semaglutide users do not exist.

Who should not take semaglutide, and who needs extra caution

The label lists two absolute contraindications:

• A personal or family history of medullary thyroid carcinoma, or MEN 2.
• A prior serious allergic reaction to semaglutide or any ingredient in the product.

It also identifies situations that call for avoidance or closer supervision:

• Pregnancy: semaglutide may cause fetal harm based on animal studies, and weight loss offers no benefit during pregnancy. For people taking it for weight or cardiovascular risk, the label says to discontinue when pregnancy is recognized, and to stop at least 2 months before a planned pregnancy because of the long half-life.
• Breastfeeding: breastfeeding is not recommended while taking the weight-management semaglutide tablets, because an absorption enhancer in the tablet passes into milk. For the injection, there are no data on whether it passes into human milk.
• Severe gastroparesis: not recommended.
• History of pancreatitis or gallbladder disease: discuss with your prescriber; these are the organs most affected by the serious warnings.
• Diabetic retinopathy: monitoring for progression is advised.
• Kidney impairment: kidney side effects were more frequent in people with existing impairment, mainly through dehydration.
• Insulin or sulfonylurea use: higher risk of low blood sugar.
• Other GLP-1 drugs: the label says not to combine semaglutide products with each other or with any other GLP-1 receptor agonist. This includes tirzepatide; see how tirzepatide and semaglutide compare.
• Oral medications that need precise levels: delayed stomach emptying can change absorption. In one study with the tablet form, exposure to the thyroid medication levothyroxine rose by 33%. The label advises closer monitoring of drugs with a narrow therapeutic range.
• Adults 75 and older: very few were included in the weight-loss trials (23 people, about 1%), so side effect data in this group are thin.

When to seek urgent care

Call your prescriber promptly, or go to an emergency department if symptoms are severe, for any of the following. These follow the warning signs in the FDA-approved Medication Guide and the European safety review.

• Severe abdominal pain that will not go away, with or without vomiting, especially if it spreads to your back (possible pancreatitis). The Medication Guide says to stop using the drug and call right away.
• Pain in the upper abdomen with fever, yellowing of the skin or eyes, or clay-colored stools (possible gallbladder problem).
• Vomiting or diarrhea that does not go away, an inability to keep fluids down, very little urine, or lightheadedness when standing (dehydration and possible kidney injury).
• Swelling of the face, lips, tongue, or throat, trouble breathing or swallowing, severe rash, fainting, or a very rapid heartbeat (serious allergic reaction). This is an emergency.
• Severe bloating with inability to pass stool or gas, or persistent vomiting of undigested food (possible obstruction or severe gastroparesis).
• Sudden loss of vision or rapidly worsening eyesight.
• A lump or swelling in the neck, persistent hoarseness, or trouble swallowing.
• Signs of low blood sugar if you have diabetes: shakiness, sweating, confusion, slurred speech, or drowsiness.
• A racing or pounding heartbeat at rest that lasts several minutes.
• Thoughts of harming yourself. In the US, call or text 988.

Myths versus realities

Myth: the nausea lasts as long as you take the drug

Reality: in the pooled STEP trials the median episode of nausea lasted 8 days, and the share of people with nausea at any one time peaked near week 20 and then declined. Constipation is the exception and often persists.

Myth: if you do not feel sick, it is not working

Reality: less than 1 percentage point of semaglutide's additional weight loss was explained by digestive side effects. People without them lost nearly as much weight.

Myth: semaglutide causes thyroid cancer in people

Reality: it causes thyroid C-cell tumors in rodents. Whether it does so in humans is unknown. Observational studies conflict, and the largest found no increase over about four years. The contraindication for people with MTC or MEN 2 in the family is a precaution taken seriously because the question is open.

Myth: "stomach paralysis" is common

Reality: slower stomach emptying is an expected, labeled effect of the drug. Diagnosed gastroparesis appears uncommon; the one claims-based estimate was about 9 cases per 1,000 person-years, from a small sample. It is rare enough to be unlikely for any one person and real enough that persistent vomiting should never be ignored.

Questions to ask your prescriber

1. Do I have any contraindication, including a family history of medullary thyroid cancer or MEN 2?
2. What is the plan if I cannot tolerate a dose increase? Can escalation be delayed, and is 1.7 mg a reasonable long-term dose for me?
3. Which of my current medications might need adjusting as I eat less and lose weight, such as insulin, sulfonylureas, blood pressure drugs, or levothyroxine?
4. Is the product you are prescribing an FDA-approved pen or tablet, or a compounded product? If compounded, how is the dose measured and who makes it?
5. What symptoms should make me call you the same day, and what should send me to the emergency department?
6. I have a procedure or surgery coming up. Who will coordinate the plan with the anesthesia team?
7. How will we monitor for muscle loss, and what protein intake and strength training do you suggest for me?
8. If I have diabetic eye disease, how often should my eyes be checked?
9. I am planning a pregnancy. When should I stop?
10. What should I do if I miss two or more doses?

Semaglutide is one option among several, and the right choice depends on your health history and goals. An overview of semaglutide as a treatment and the broader medical weight loss options can help you prepare for that conversation.

This is general information, not medical advice. Whether a treatment is right for you is determined by a licensed provider after an evaluation.