Semaglutide (Ozempic, Wegovy, Rybelsus): The Complete Guide

Semaglutide is a medication that mimics the hormone GLP-1: it increases fullness, reduces hunger, slows the emptying of the stomach and helps control blood sugar. Novo Nordisk sells it under three brand names. In the US, Ozempic (a weekly injection, now also sold as a daily tablet) and Rybelsus (a daily tablet) are approved for type 2 diabetes. Wegovy (a weekly injection or a daily tablet) is approved for weight management in people with obesity, or with overweight and at least one weight-related condition, and to lower cardiovascular risk in some of them^[1,2,3]. In the STEP 1 trial, in people without diabetes, Wegovy lowered weight by 14.9% on average over 68 weeks, compared with 2.4% on placebo^[11]. Its most common side effects are digestive^[2].

Here I bring together what the US labels (FDA), the EU labels (EMA) and the main trials say. Label facts have a dotted underline and the date I checked them. The decision to start, adjust or stop semaglutide is always made by your prescriber, with you.

What semaglutide is and how it works in the body

Semaglutide is a GLP-1 receptor agonist: it switches on the receptor for GLP-1 (glucagon-like peptide-1), a hormone your body makes. The US Wegovy label calls GLP-1 a physiological regulator of appetite and caloric intake, and describes semaglutide as an analog with 94% sequence homology to human GLP-1^[2]. Its half-life is approximately 1 week^[2], which is why the injections are weekly.Dotted underline: a drug-label fact; hover over it to see the date it was checked.

The US label sums up the effect on weight in one line: semaglutide decreases calorie intake, and the effect is likely mediated by appetite^[2]. The EU label, in section 5.1, goes into more detail. It acts on three fronts^[5]:

• Appetite and fullness. The GLP-1 receptor is found in areas of the brain that regulate appetite^[2]. In trials, semaglutide increased feelings of fullness and satiety, lowered hunger, improved control of eating, reduced food cravings and lowered the preference for high-fat food. In a phase 1 trial, energy intake during an ad libitum meal was 35% lower than with placebo after 20 weeks^[5].
• Stomach emptying. It slightly delays the passage of food from the stomach to the intestine, mostly right after meals. The US Ozempic label describes a minor delay in gastric emptying in the early postprandial phase, and reports no apparent effect on the rate of gastric emptying with semaglutide 2.4 mg^[1].
• Blood sugar. It stimulates insulin release and lowers glucagon in a glucose-dependent manner, that is, when blood sugar is high^[1]. The risk of low blood sugar (hypoglycemia) rises mainly when it’s used with insulin or an insulin secretagogue, such as a sulfonylurea^[1,2].

How it fits into the wider family, including tirzepatide, is in what GLP-1 medications are.

Ozempic, Wegovy and Rybelsus: how the three brands differ

All three contain the same active ingredient; the approved use, the form, the doses and the price differ. This table summarizes the US labels.

Sources: sections 1 and 3 of the US labels for Ozempic, Wegovy and Rybelsus and Ozempic tablets^[1,2,3]; approval dates from Drugs@FDA^[7,8,9,10]. MASH: metabolic dysfunction-associated steatohepatitis, a fatty liver disease with inflammation.

A few points worth knowing:

• BMI in the US labels. The US Wegovy indication gives no BMI (body mass index) cut-offs; its trials enrolled adults with a BMI of 30 or more, or 27 to 29.9 with a condition such as high blood pressure or high cholesterol^[2]. See what BMI measures.
• Rybelsus and Ozempic tablets aren’t interchangeable. “Ozempic tablets” is the name the FDA approved in January 2026 for the newer 1.5, 4 and 9 mg formulation, first sold as Rybelsus^[8]. The two share one US label, which warns that they are not substitutable on a mg-to-mg basis. The label estimates an absolute bioavailability of about 0.4% to 1% for Rybelsus and 1% to 2% for Ozempic tablets^[3].
• Wegovy tablets. The US label notes that Wegovy tablets have not been studied for weight reduction in adults with type 2 diabetes^[2]. More in the Wegovy pill.
• The EU labels are narrower. There, Ozempic and Rybelsus are approved for type 2 diabetes only, and the heart results appear in the trial section, not as an indication^[4,6]. Wegovy covers weight management in adults with a BMI of 30 or more, or 27 to 30 with at least one weight-related condition, and in teens 12 and older with obesity and a body weight above 60 kg (132 lb)^[5]. The EU sells only Rybelsus tablets, in 1.5, 4, 9, 25 and 50 mg^[6]. Spain and Latin America are covered in the Spanish version of this guide (in Spanish), and generic semaglutide by country in generic semaglutide: patents and approvals.

For a closer look at the two injections, see Ozempic vs. Wegovy, and for Wegovy against tirzepatide, Zepbound vs. Wegovy.

What the clinical trials show

The headline numbers come from a few large placebo-controlled trials funded by Novo Nordisk. It pays to look at who was studied, for how long, and the difference from placebo.

95% CI: 95% confidence interval, the range where the true effect probably lies. HR (hazard ratio): compares the risk between the two groups over time; 0.80 means a 20% lower relative risk. HbA1c: average blood sugar over the past two to three months. The US Wegovy label describes these trials under numbers: SELECT is Study 1, STEP 1 is Study 2, STEP 2 is Study 3 and STEP 4 is Study 5^[2]. All the weight-loss trials can be compared side by side in the trial results chart.

STEP 1: obesity or overweight without diabetes

In STEP 1, 86.4% of people on semaglutide lost at least 5% of their weight (31.5% on placebo) and 50.5% lost at least 15% (4.9%). The average loss was 15.3 kg (33.7 lb) vs. 2.6 kg (5.7 lb), and individual responses vary a lot. Digestive symptoms led 4.5% to stop treatment, vs. 0.8% on placebo^[11]. More in how much weight people lose on GLP-1 medications.

STEP 2: type 2 diabetes

With type 2 diabetes, 68.8% lost at least 5% of their weight, vs. 28.5% on placebo; a third group on 1 mg, the Ozempic dose, served as a comparison^[12]. The US Wegovy label states it plainly: weight reduction was smaller in patients with type 2 diabetes than in those without^[2].

SELECT: the first heart result in obesity without diabetes

SELECT measured heart attacks, strokes and cardiovascular deaths, not weight. The 6.5% vs. 8.0% rate of major events is 1.5 percentage points fewer over an average of a little over three years^[14]. Cardiovascular death on its own gave a hazard ratio of 0.85 (95% CI: 0.71 to 1.01), and the label notes that superiority was not confirmed^[2]. SELECT is the basis for Wegovy’s US cardiovascular indication^[2].

Everyone in it had already had a cardiovascular problem, so the absolute benefit doesn’t carry over as is to someone without that history. More people also stopped treatment because of side effects: 16.6% on semaglutide vs. 8.2% on placebo^[14].

SUSTAIN-6 and SOUL: type 2 diabetes and the heart

SUSTAIN-6 tested the Ozempic doses (0.5 and 1 mg) in type 2 diabetes with high cardiovascular risk. Designed to show that semaglutide didn’t raise cardiovascular risk, it’s the trial behind Ozempic’s US cardiovascular indication^[1]. It also showed a signal: complications of diabetic retinopathy, an eye disease caused by diabetes, were more common on semaglutide (HR 1.76; 95% CI: 1.11 to 2.78)^[13], covered under warnings below.

The pills have their own heart trial, SOUL: 9,650 adults with type 2 diabetes and cardiovascular disease, chronic kidney disease or both took semaglutide tablets 14 mg or placebo, with a median follow-up of 49.6 and 49.4 months; a major cardiovascular event occurred in 12% vs. 13.8% (HR 0.86; 95% CI: 0.77 to 0.96)^[3]. It’s the basis for the tablets’ US cardiovascular indication^[3].

How the dose is stepped up, according to the label

Semaglutide is increased in steps to reduce digestive side effects. I reproduce the schedules as they appear in the US labels so you know what the official document says. This is not a dosing recommendation: your prescriber decides the actual schedule and can adapt it to how you tolerate it, to your indication and to your other treatments.

Wegovy injection (weekly)

Source: US Wegovy label, section 2.2, Table 1^[2]. If a dose isn’t tolerated, it tells prescribers to consider delaying dosage escalation for 4 weeks. It limits the optional 7.2 mg step to adults who tolerate 2.4 mg for at least 4 weeks and for whom additional weight reduction is clinically indicated^[2]; whether that applies to anyone is the prescriber’s judgment. For teens 12 and older and for cardiovascular risk reduction, the maintenance dose is 2.4 mg (recommended) or 1.7 mg; for MASH, 2.4 mg, which can be lowered to 1.7 mg if it isn’t tolerated^[2].

Wegovy tablets (daily)

Source: US Wegovy label, section 2.3, Table 2^[2].

Ozempic injection (weekly)

Source: US Ozempic label, section 2.2^[1]. In type 2 diabetes with chronic kidney disease, the label sets a maintenance dose of 1 mg, after at least 4 weeks on 0.5 mg^[1].

Rybelsus and Ozempic tablets (daily)

Source: US label for Rybelsus and Ozempic tablets, section 2.2^[3].

All the semaglutide tablets come with the same instructions in the US labels: once a day on an empty stomach in the morning, swallowed whole with up to 4 ounces (120 mL) of water and no other liquid, followed by a wait of at least 30 minutes before eating, drinking or taking other oral medications^[2,3]. In the label’s absorption studies, semaglutide absorption was higher after a longer fasting period following the dose^[3]. Absorption also varies a lot from person to person: the US Wegovy label notes higher variability in semaglutide concentrations with the tablets than with the injection^[2], and the EU Rybelsus label says 2% to 4% of patients will not have any exposure^[6].

Side effects and how often they happen, according to the label

The most common side effects are digestive and concentrate in the dose-escalation phase. This table shows selected rows from Table 3 of the US Wegovy label, which lists the adverse reactions reported in at least 2% of adults on 2.4 mg and more often than on placebo. The figures come from 3 randomized trials with 2,116 adults on Wegovy injection treated for up to 68 weeks^[2].

The full table also lists bloating, belching, gas, gastroenteritis, gastritis and altered skin sensation (dysesthesia)^[2]. The same label adds that 73% of adults on Wegovy injection and 47% on placebo reported gastrointestinal reactions, most often during dose escalation; that these led 4.3% on Wegovy and 0.7% on placebo to stop treatment permanently; and that severe gastrointestinal reactions occurred in 4.1% vs. 0.9%^[2]. The EU label gives how long they lasted: a median of 8 days for nausea, 3 days for diarrhea, 2 days for vomiting and 47 days for constipation^[5]. Other figures from the US label^[2]:

• Gallstones: cholelithiasis in 1.6% on Wegovy injection vs. 0.7% on placebo, and gallbladder inflammation (cholecystitis) in 0.6% vs. 0.2%, in adults in the weight-loss trials.
• Hair loss: 3.3% vs. 1% in a pool of three trials (4% of women and 0.9% of men). The label links it to weight reduction.
• Heart rate: mean increases in resting heart rate of 1 to 4 beats per minute.
• Low blood pressure and fainting: reactions related to low blood pressure in 1.3% vs. 0.4%, and fainting in 0.8% vs. 0.2%.
• Confirmed acute pancreatitis: 4 adults on Wegovy (0.2 cases per 100 patient-years) vs. 1 on placebo (less than 0.1).
• The 7.2 mg dose: altered skin sensation (dysesthesia) in 22% on 7.2 mg, 6% on 2.4 mg and 0.3% on placebo, and hair loss in 5.8%, 3.3% and 1.0%.
• After approval: the label lists reports of ileus, intestinal obstruction and severe constipation including fecal impaction, anaphylaxis, angioedema and acute kidney injury.

At the diabetes doses, side effects are similar but less frequent. In the US Ozempic label, nausea affected 15.8% on 0.5 mg and 20.3% on 1 mg vs. 6.1% on placebo, and diarrhea 8.5% and 8.8% vs. 1.9%^[1]. With Rybelsus, nausea affected 11% on 7 mg and 20% on 14 mg vs. 6% on placebo, and decreased appetite 6% and 9% vs. 1%^[3]. With Ozempic and a sulfonylurea, severe hypoglycemia occurred in 0.8% on 0.5 mg and 1.2% on 1 mg^[1].

For practical help, see GLP-1 nausea and what to eat, constipation on GLP-1 medications and hair loss on GLP-1 medications. The symptom diary can help you bring a clear record to your appointment.

Safety signals reviewed by regulators

Only what regulators have concluded, with its date.

Optic neuropathy (NAION): a very rare side effect in the EU label

On June 6, 2025, the EMA’s safety committee (PRAC) concluded that non-arteritic anterior ischemic optic neuropathy (NAION), damage to the optic nerve, is a very rare side effect of semaglutide: it may affect up to 1 in 10,000 people treated^[16]. The EU Wegovy label says epidemiological studies in adults with type 2 diabetes suggest an approximately two-fold increase in relative risk, about one additional case per 10,000 person-years of treatment, and that a sudden loss of vision should lead to an eye examination, and treatment should be stopped if NAION is confirmed^[5].

Here the US and EU labels differ. In the US label versions I checked (Ozempic and Wegovy, revised June 2026; Rybelsus and Ozempic tablets, revised January 2026), NAION isn’t listed among the warnings or the reactions reported after approval^[1,2,3]. Either way, sudden or rapidly worsening vision loss is a reason to see a doctor without delay.

Suicidal thoughts: no causal link, according to the EMA and the FDA

In April 2024, the PRAC concluded that the available evidence doesn’t support a causal link between GLP-1 receptor agonists, semaglutide included, and suicidal or self-harm thoughts and actions^[18].

The FDA reached the same place on January 13, 2026. After reviewing a meta-analysis of 91 placebo-controlled trials with 107,910 patients and a claims-data study of 2.2 million people, it found no increased risk and asked the makers of Saxenda, Wegovy and Zepbound to remove the warning from their labels^[17]. The current US Wegovy label lists its former section 5.10, Suicidal Behavior and Ideation, as removed in February 2026^[2]. If you notice mood changes during any treatment, tell your doctor; in a crisis in the US, call or text 988, the Suicide & Crisis Lifeline^[17].

Thyroid tumors: the US boxed warning

Every US semaglutide label opens with a boxed warning, the FDA’s most prominent kind: in rodents, semaglutide causes thyroid C-cell tumors at clinically relevant exposures, and it’s unknown whether it causes them, including medullary thyroid carcinoma (MTC), in humans^[1,2,3]. For that reason, in the US it’s contraindicated in people with a personal or family history of MTC or with multiple endocrine neoplasia syndrome type 2 (MEN 2), a rare inherited condition^[1,2,3]. The labels ask prescribers to explain the symptoms of thyroid tumors, such as a mass in the neck, trouble swallowing, shortness of breath or persistent hoarseness, and say that routine monitoring of calcitonin or thyroid ultrasound is of uncertain value for early detection^[1,2,3]. The EU labels don’t include that contraindication^[4,5,6].

Anesthesia, sedation and a full stomach

The US and EU labels describe pulmonary aspiration (stomach contents getting into the lungs) in people taking GLP-1 receptor agonists during general anesthesia or deep sedation^[1,2,5]. The US labels speak of rare postmarketing reports in people who had residual gastric contents despite following preoperative fasting recommendations, and say that available data are insufficient to inform recommendations, including whether changing fasting or temporarily stopping the drug would reduce retained gastric contents. They ask patients to inform healthcare providers before any planned surgery or procedure^[1,2,3].

Counterfeits and “compounded semaglutide”

This risk is in regulators’ alerts, not the labels. In October 2023, the EMA warned of falsified Ozempic pens found at wholesalers in the EU and the UK^[19].

The FDA warns that compounded drugs aren’t FDA-approved: it doesn’t review them for safety, effectiveness or quality before they’re sold. As of May 31, 2026, it had received 990 adverse event reports associated with compounded semaglutide, and it describes reports, some requiring hospitalization, that may be related to dosing errors with compounded injections. It also points out that semaglutide salts (sodium or acetate) are different active ingredients from the one in the approved drugs, and that counterfeit products may contain the wrong ingredient, too much or too little, or none at all^[20]. That’s why this site has no purchase links or sourcing information: semaglutide is a prescription drug, dispensed by licensed pharmacies. Why compounded semaglutide isn’t a generic is in generic semaglutide: patents and approvals.

Contraindications and warnings in the label

Besides the thyroid contraindication above, the US labels contraindicate semaglutide after a prior serious hypersensitivity reaction to semaglutide or any of the product’s ingredients^[1,2,3]; in the EU, hypersensitivity is the only contraindication^[4,5,6]. The main warnings:

• Pancreatitis. The US labels describe its typical sign as persistent or severe abdominal pain, sometimes radiating to the back, with or without nausea or vomiting, and tell prescribers to stop semaglutide if pancreatitis is suspected^[1,2,3]. The EU label adds that if confirmed, semaglutide should not be restarted^[5].
• Low blood sugar. The risk rises with sulfonylureas or insulin, and the labels have the prescriber consider reducing the dose of the insulin or insulin secretagogue^[1,2]. The US Wegovy label notes that use in type 1 diabetes or with insulin has not been evaluated^[2]. The EU labels add that semaglutide is not a substitute for insulin^[4,5], and report diabetic ketoacidosis in insulin-dependent patients whose insulin was rapidly reduced or stopped^[4,6].
• Diabetic retinopathy. In SUSTAIN-6, complications occurred in 3.0% on semaglutide vs. 1.8% on placebo: 8.2% vs. 5.2% in people with known retinopathy, and 0.7% vs. 0.4% in those without. The label notes that rapid improvement in glucose control has been associated with a temporary worsening of diabetic retinopathy, and that people with a history of retinopathy should be monitored^[1].
• Dehydration and kidneys. The US labels describe postmarketing reports of acute kidney injury, some requiring dialysis, mostly in people whose nausea, vomiting or diarrhea led to dehydration, and ask prescribers to monitor kidney function in that situation^[1,2].
• Gastroparesis. Semaglutide is not recommended in patients with severe gastroparesis, a condition in which the stomach empties very slowly^[1,2,3].
• Heart rate. The US Wegovy label asks patients to report palpitations or a racing heartbeat at rest, and tells prescribers to discontinue Wegovy if a sustained increase in resting heart rate occurs^[2].
• Never share a pen. The Ozempic pen and the multi-dose Wegovy FlexTouch pen must never be shared between patients, even if the needle is changed, because of the risk of passing on blood-borne infections^[1,2].
• Combinations and populations not studied. The US Wegovy label advises against using it with other semaglutide-containing products or any other GLP-1 receptor agonist^[2]; the EU label, also with other weight-management products, in severe kidney impairment (eGFR below 30), in severe liver impairment or in NYHA class IV heart failure, where it hasn’t been studied^[5].
• Pregnancy and breastfeeding. The US Wegovy label says weight loss offers no benefit to a pregnant patient and may cause fetal harm; Wegovy used for weight reduction should be discontinued when a pregnancy is recognized^[2]. The US Ozempic and Rybelsus labels allow use in pregnancy only if the potential benefit justifies the potential risk to the fetus^[1,3]. All three US labels say to stop semaglutide at least 2 months before a planned pregnancy, because of its long half-life^[1,2,3], timing to plan with your prescriber. The EU labels are stricter: semaglutide should not be used during pregnancy or breastfeeding, and they recommend contraception for women who could become pregnant^[4,5,6]. On breastfeeding, the US labels don’t recommend it during treatment with the tablets, because of their absorption enhancer (SNAC), while for the injections they ask doctor and patient to weigh the benefits of breastfeeding against the possible risks^[1,2,3].
• Other medicines. Slower stomach emptying may change how oral medicines are absorbed. With semaglutide tablets, levothyroxine exposure increased 33%, and the US labels suggest more clinical or laboratory monitoring for oral drugs with a narrow therapeutic index^[2,3]. In the US label’s studies, the pharmacokinetics of warfarin showed no clinically significant differences^[3]; the EU labels still recommend frequent INR monitoring when semaglutide is started in people taking warfarin or other coumarins^[4,5].

What to eat and how to keep muscle

The labels present semaglutide as an addition to diet and physical activity, not a replacement: Wegovy is approved in combination with a reduced-calorie diet and increased physical activity^[2]. In most of its weight trials, participants were counseled on a reduced-calorie diet (a deficit of about 500 kcal a day) and physical activity (at least 150 minutes a week)^[2]. The results above were obtained under those conditions.

With a smaller appetite, the challenge is eating well with less hunger: enough protein, fiber, fluids and nutrients in smaller portions, not eating as little as possible. If food starts to make you anxious, if you skip meals for fear of symptoms, or if your relationship with food gets worse, ask a healthcare professional for help.

On muscle, the US Wegovy label states that semaglutide lowers body weight with greater fat mass loss than lean mass loss^[2]. The EU label gives the detail: in a STEP 1 substudy of 140 people measured by DEXA (a body-composition scan), fat mass fell more than lean mass, and visceral fat fell too^[5]. Part of the weight lost is still lean mass, so protein and strength training are worth discussing with your doctor or a dietitian:

• What to eat on GLP-1 medications, by phase and by symptom.
• Protein and muscle on GLP-1 medications, on the evidence about lean mass.
• The protein calculator, to estimate a daily target to discuss with your healthcare professional.

What happens when you stop semaglutide

Much of the weight lost comes back after treatment stops; the decision to stop, reduce or change treatment belongs to your prescriber, with you. Two studies measured it.

The STEP 1 extension. A subgroup of 327 participants was followed for one year after the 68 weeks of treatment ended, when both the drug and the lifestyle program stopped. According to the study published in 2022 (summary), those on semaglutide had lost an average of 17.3% of their weight by week 68. A year later they had regained 11.6 percentage points, for a net loss of 5.6% at week 120; on placebo, the net loss was 0.1%. Most cardiometabolic improvements drifted back toward their starting values; the authors sum it up as regaining two-thirds of the earlier loss. It’s an exploratory analysis of a small subgroup^[15].

STEP 4. The US Wegovy label describes this trial as Study 5, with 902 people. All received semaglutide for a 20-week run-in; those who reached 2.4 mg were then randomized to continue or switch to placebo. Between weeks 20 and 68, weight kept falling by 7.9% in those who continued and rose by 6.9% in those switched to placebo: a difference of −14.8 points (95% CI: −16.0 to −13.5)^[2]. By my own rough arithmetic, not a figure the label reports, the placebo group (95.4 kg at week 20) ended near 102 kg (225 lb), still below the 107.2 kg (236 lb) average of all randomized patients at the start of the run-in^[2]. The label warns that because people who didn’t tolerate escalation weren’t randomized, the results may not reflect the experience of patients who are first starting Wegovy^[2]. Details are in the STEP 4 summary.

With a half-life of about a week, semaglutide also stays in the body after the last dose: the US Wegovy label says about 5 to 7 weeks after the last 2.4 mg or 7.2 mg injection or 25 mg tablet^[2], and the US Ozempic label, about 5 weeks^[1]. What tends to happen to appetite and weight afterward is in what happens when you stop Ozempic, Wegovy or Zepbound.

Price and coverage

In the US, what you pay depends on your insurance, your plan’s rules and the drug’s approved use, and prices change often, so I don’t repeat figures here. The monthly cost calculator shows dated, sourced list prices for the US, Spain and Mexico. Coverage questions are for your prescriber and your insurer.

Frequently asked questions

Is semaglutide the same as Ozempic?

Semaglutide is the active ingredient; Ozempic is one of its brand names, alongside Wegovy and Rybelsus^[1,2,3]. A product sold simply as “semaglutide” is not an FDA-approved generic: the FDA doesn’t review compounded semaglutide for safety, effectiveness or quality, and some compounders use salt forms that are different active ingredients^[20].

How does Ozempic work?

Ozempic’s active ingredient, semaglutide, is a GLP-1 analogue with 94% sequence homology to human GLP-1 that selectively binds to and activates the GLP-1 receptor^[1]. Section 12.1 of the US Ozempic label says it stimulates insulin secretion and lowers glucagon secretion, both in a glucose-dependent manner, and causes a minor delay in gastric emptying in the early postprandial phase^[1]. In plain words, it helps the body release insulin when blood sugar is high and holds back the hormone that raises it. Binding to albumin, a blood protein, gives it its long half-life, which is why it’s injected once a week^[1]. The Wegovy label, same active ingredient, adds the effect on appetite: semaglutide decreases calorie intake, and the effect is likely mediated by appetite^[2].

Are Ozempic and Wegovy the same drug?

Same active ingredient and maker, but different medicines: different approved uses (type 2 diabetes vs. weight management), pens and top weekly doses: 2 mg for Ozempic^[1] vs. 2.4 mg, or 7.2 mg with Wegovy HD^[2]. The full comparison is in Ozempic vs. Wegovy.

Can Ozempic be used for weight loss?

In the US, Ozempic’s label covers only uses tied to type 2 diabetes^[1]. The semaglutide approved for weight management is Wegovy^[2]. Using a medicine outside its approved use (off-label) is a clinical decision for your doctor.

Does semaglutide cause thyroid cancer?

It caused thyroid C-cell tumors in rodents; whether it does in humans is unknown, which is why the US labels contraindicate it with a personal or family history of medullary thyroid carcinoma or MEN 2^[1,2,3]. If you have a history of thyroid disease, tell your prescriber.

Is Ozempic safe?

The FDA has approved Ozempic for blood sugar control in adults with type 2 diabetes, alongside diet and exercise, and for lowering cardiovascular and kidney risks in some adults with type 2 diabetes^[1,7]. Its label opens with a boxed warning: in rodents, semaglutide causes thyroid C-cell tumors at clinically relevant exposures, and it’s unknown whether it causes them in humans, so it’s contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2^[1]. The other warnings in section 5 cover acute pancreatitis, diabetic retinopathy complications, never sharing a pen between patients, low blood sugar with insulin or drugs that boost insulin release such as a sulfonylurea, acute kidney injury from dehydration, severe gastrointestinal reactions, allergic reactions, gallbladder disease and pulmonary aspiration during anesthesia or deep sedation^[1]. The FDA also warns that compounded semaglutide isn’t FDA-approved and isn’t reviewed for safety, effectiveness or quality^[20]. Whether the benefits outweigh the risks depends on the person, their history and their other medicines, so that’s for the prescriber to weigh with you.

What happens if a dose is missed?

The rules differ by product: for Ozempic injection, the label sets a 5-day window after the missed dose^[1]; the Wegovy injection label looks at how many days remain until the next scheduled dose; and the daily tablets follow a different rule again^[2,3]. If two or more Wegovy injections in a row have been missed, the label tells the prescriber to restart dose escalation at a lower dose^[2]. Your prescriber decides how that applies to you; the Medication Guide explains it, and your pharmacist can answer questions.

Do I need to tell my doctor before surgery or an endoscopy with sedation?

Yes. The labels describe pulmonary aspiration during anesthesia or deep sedation in people taking GLP-1 receptor agonists, and ask patients to tell their healthcare providers about any planned procedure^[1,2,3,5]. What to do with the medication beforehand is decided by the team treating you.

Does semaglutide interfere with birth control pills?

In the US Ozempic label’s studies, semaglutide injection had no clinically relevant interaction with an oral contraceptive containing ethinylestradiol and levonorgestrel^[1], and the label for the tablets found no clinically significant differences in ethinyl estradiol or levonorgestrel levels^[3]. If vomiting or diarrhea is severe, ask your doctor or pharmacist how that affects your method.

Before you decide anything, talk to your prescriber

Semaglutide has benefits measured in large trials, well-described side effects and open questions, such as the long term after stopping. The indication, the schedule, the adjustments and the decision to continue or stop are your doctor’s, with you.

Before an appointment, write down your symptoms, your other medicines and your questions; the doctor visit checklist can help. I review this page every quarter, and sooner if a label changes or a regulator publishes something new.