Wegovy

Semaglutide is an anti-diabetic medication used for the treatment of type2 diabetes and an anti-obesity medication used for long-term weight management. It is a peptide similar to the hormone glucagon-like peptide-1 (GLP-1), modified with a side chain. It can be administered by subcutaneous injection or taken orally. It is sold by Novo Nordisk under the brand names Ozempic and Rybelsus for diabetes, and under the brand name Wegovy for weight management and weight loss.

Semaglutide is a glucagon-like peptide-1 receptor agonist. The most common side effects include nausea, vomiting, diarrhea, abdominal pain, and constipation.

It was approved for medical use in the US in 2017. In 2022, it was the 48th most commonly prescribed medication in the United States, with more than 13million prescriptions.

Medical uses

In the US, semaglutide is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type2 diabetes; and to reduce the risk of major adverse cardiovascular events in adults with type2 diabetes and established cardiovascular disease.

In the US semaglutide (Wegovy) is indicated, in combination with a reduced calorie diet and increased physical activity, to reduce the risk of major adverse cardiovascular events (cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke) in adults with established cardiovascular disease and who are either obese or overweight; to reduce excess body weight and maintain weight reduction long term in people aged twelve years of age and older with obesity or adults with overweight in the presence of at least one weight-related comorbid condition.

In the EU, semaglutide is indicated for the treatment of adults with insufficiently controlled type2 diabetes as an adjunct to diet and exercise as monotherapy when metformin is considered inappropriate due to intolerance or contraindications; in addition to other medicinal products for the treatment of diabetes.

In the EU, semaglutide (Wegovy) is indicated as an adjunct to a reduced-calorie diet and increased physical activity for weight management, including weight loss and weight maintenance, in adults with obesity (initial body mass index (BMI) ≥ 30kg/m²) or who are overweight (initial BMI ≥ 27kg/m²) and have at least one weight-related comorbidity (e.g. dysglycemia (pre-diabetes or type2 diabetes), hypertension, dyslipidemia, or cardiovascular disease). It is also indicated as an adjunct to a reduced-calorie diet and increased physical activity for weight management in adolescents (aged twelve years of aged and older) with obesity and body weight above .

Side effects

Possible adverse effects include nausea, diarrhea, vomiting, constipation, abdominal pain, headache, fatigue, indigestion/heartburn, dizziness, abdominal distension, belching, hypoglycemia (low blood glucose) in people with type2 diabetes, flatulence, gastroenteritis, and gastroesophageal reflux disease (GERD). It has in the past been suspected to cause pancreatitis, and can cause gastroparesis, and bowel obstruction. Among people who were prescribed a GLP-1, 0.1% were diagnosed with gastroparesis at least six months later, which equates to a 52% increased risk of being diagnosed with gastroparesis while on a GLP-1 medication. A 2019 meta-analysis did not indicate a significantly elevated risk of acute pancreatitis.

The US Food and Drug Administration prescription label for semaglutide contains a boxed warning for thyroid C-cell tumors in rodents. It is unknown whether semaglutide causes thyroid C-cell tumors, including medullary thyroid carcinoma, in humans.

A 2025 observational study reported a modest increased risk of a serious eye condition in people with diabetes taking GLP-1 receptor agonists. The analysis found that individuals using these medications had a slightly higher incidence of neovascular age-related macular degeneration (nAMD)—a form of vision loss that can lead to blindness—compared to similar individuals not on the drugs. After one year, 0.2% of GLP-1 users developed nAMD versus 0.1% among non-users. The study, which analyzed health data from nearly 140,000 patients in Canada, controlled for socioeconomic and health-related factors. The average participant age was 66. Since the risk factors for nAMD overlap with those of people prescribed GLP-1s, such as diabetes and related conditions, researchers investigated this potential link following reports of other eye-related side effects in patients on GLP-1 therapies.

Contraindications

Semaglutide is contraindicated in people with a personal or family history of medullary thyroid carcinoma or in people with multiple endocrine neoplasia type 2.

Mechanism of action

Semaglutide is a glucagon-like peptide-1 receptor agonist. The drug decreases blood sugar levels. The decrease is theorized to be caused by the mimicking of glucagon-like peptide-1 (GLP-1), an incretin. It also appears to enhance growth of pancreatic beta cells, which are responsible for insulin production and release. Additionally, it inhibits the production of glucagon, the hormone that increases glycogenolysis (release of stored carbohydrate from the liver) and gluconeogenesis (synthesis of new glucose). It reduces food intake by lowering appetite and slowing down digestion in the stomach, helping reduce body weight.

Structure and pharmacology

Semaglutide is chemically similar to human GLP-1. The first six amino acids of GLP-1 are missing. Substitutions are made at GLP positions 8 and 34 (semaglutide positions 2 and 28), where alanine and lysine are replaced by 2-aminoisobutyric acid and arginine, respectively. The substitution of the alanine prevents chemical breakdown by dipeptidyl peptidase-4. The lysine at GLP position 26 (semaglutide position 20) has a long chain attached, ending with a chain of 18 carbon atoms and a carboxyl group. This increases the drug's binding to blood protein (albumin), which enables longer presence in the blood circulation.

Semaglutide's half-life in the blood is about seven days (165–184 hours).

History

In the 1970s, Jens Juul Holst and Joel Habener began research on the GLP-1 hormone, initially in relation to duodenal ulcer disease. They were examining hormones secreted during eating, and testing them on pig pancreases, leading to the discovery of GLP-1's significant potency in 1988. Their work, which later contributed significantly to diabetes and obesity treatments, earned them and Daniel J. Drucker the 2021 Warren Alpert Foundation Prize.

Research continued and in 1993 Michael Nauck managed to infuse GLP-1 into people with type 2 diabetes, stimulating insulin while inhibiting glucagon and bringing blood glucose to normal levels. However, treating diabetes patients with GLP-1 hormones resulted in significant side effects, leading researchers financed by Novo Nordisk to start looking to develop a suitable compound for therapeutic use.

In 1998 a team of researchers at Novo Nordisk led by the scientist Lotte Bjerre Knudsen developed liraglutide, a glucagon-like peptide-1 receptor agonist that could be used to treat diabetes.

Clinical trials and early approvals for diabetes

In June 2008, a phase II clinical trial began studying semaglutide, a once-weekly diabetes therapy as a longer-acting alternative to liraglutide. It was given the brand name Ozempic. Clinical trials started in January 2016 and ended in May 2017.

The US Food and Drug Administration (FDA) approved semaglutide based on evidence from seven clinical trials of 4087 participants with type2 diabetes. The trials were conducted at 536 sites in 33 countries, including Canada, Mexico, Russia, Ukraine, Turkey, India, South Africa, Japan, Hong Kong, multiple European countries, Argentina, and the United States. In two of these trials (NCT02054897 and NCT02305381), participants were randomly assigned to receive either semaglutide or placebo injection weekly. Neither the participant nor the health care provider knew which treatment was being given until after the trials were completed. Treatment was given for 30 weeks. In the other five trials (NCT01930188, NCT01885208, NCT02128932, NCT02207374, and NCT02254291), participants were randomly assigned to receive either semaglutide or another anti-diabetic medication, and the participant and provider knew which medication was being given in four trials. Treatment was given for 30 weeks or 56 weeks.

In each trial, HbA1c was measured from the start of the trial to the end of the trial and compared between the semaglutide group and the other groups.

The FDA also considered data from one separate trial (NCT01720446) of 3297 participants with type2 diabetes who were at high risk for cardiovascular events. This trial was conducted in 20 countries: multiple European countries, Russia, Turkey, Brazil, Israel, Malaysia, Mexico, Thailand, Taiwan, Canada, and the United States. The participants were randomly assigned to receive semaglutide or placebo. Neither the participant nor the health care provider knew which treatment was being given. Treatment was given for 104 weeks (2 years), and the occurrence of cardiovascular events, including heart attacks, strokes, and hospitalization due to unstable angina (near heart attack) were recorded and compared in the two groups of participants.

Trials for obesity

In March 2021, in a phase III randomized, double-blind trial, 1,961 adults with a body mass index of 30 or greater were assigned in a 2:1 ratio to a treatment with once-weekly subcutaneous semaglutide or placebo, plus lifestyle intervention. The trials occurred at 129 sites in 16 countries in Asia, Europe, North America, and South America. The mean percentage change in body weight at week 68 was −14.9% in the semaglutide group vs −2.4% with placebo, for an estimated treatment difference of −12.4 percentage points (95% CI, −13.4 to −11.5).

A 2022 review of anti-obesity treatments found that semaglutide as well as tirzepatide (which has an overlapping mechanism of action) were more promising than previous anti-obesity drugs, although less effective than bariatric surgery.

For cardiovascular health

In March 2024, the US Food and Drug Administration expanded the indication for semaglutide (brand name Wegovy) to reduce the risk of cardiovascular death, heart attack, and stroke in adults with cardiovascular disease and who are either obese or overweight. The efficacy and safety of semaglutide for this indication were studied in a multi-national, multi-center, placebo-controlled double-blind trial that randomly assigned over 17,600 participants to receive either semaglutide (Wegovy) or placebo. Participants in both groups also received standard-of-care medical treatment (e.g., management of blood pressure and cholesterol) and healthy lifestyle counseling (including diet and physical activity). Semaglutide (Wegovy) significantly reduced the risk of major adverse cardiovascular events (cardiovascular death, heart attack, and stroke), which occurred in 6.5% of participants who received semaglutide (Wegovy) compared to 8% of participants who received placebo.

Society and culture

Legal status

In December 2016, a New Drug Application was filed with the US Food and Drug Administration (FDA), and in October 2017, a FDA advisory committee approved it unanimously.

In December 2017, the injectable version with the brand name Ozempic was approved for use by people with diabetes in the United States, and, in January 2018, in Canada.

In February 2018, authorization was granted in the European Union, in March 2018 in Japan, and in August 2019 in Australia.

In September 2019, a version that can be taken orally (Rybelsus) was approved for medical use in the United States, and in the European Union in April 2020.

In June 2021, a higher-dose version for injectable use sold under the brand name Wegovy was approved by the FDA as an anti-obesity medication for long-term weight management in adults. In November 2021, the Committee for Medicinal Products for Human Use of the European Medicines Agency recommended to grant a marketing authorization for Wegovy to Novo Nordisk A/S. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged. In January 2022, Wegovy was approved for medical use in the European Union.

In January 2023, the US FDA prescription label for Rybelsus was updated to reflect that it can be used as a first-line treatment for adults with type2 diabetes.

Insurance coverage

Due to high costs, some health plans in the US do not cover weight-loss drugs like semaglutide and tirzepatide. In the United States, as of 2024, about half of private employer-sponsored plans cover these drugs, Federal Medicare Part D does not, and only a few federally-funded, state-administered Medicaid plans do so.

Generics

Semaglutide is expected to become patent-free in the United States no earlier than December 2031.

The Chinese patent was scheduled to expire in 2026, but a court ruled in 2022 that all patents on semaglutide were invalid. Novo Nordisk appealed the ruling.

In Brazil, the Supreme Court refused to extend semaglutide's patent protection, which expires in 2026.

Economics

Semaglutide was the top selling medication in the US in 2023, with expenditures of .

"Ozempic, the semaglutide injection used for T2D treatment, has a list price of $936 in the United States and $169 in Japan. Prices were $147 in Canada, $144 in Switzerland, $103 in Germany and the Netherlands, $96 in Sweden, $93 in the United Kingdom, and $87 in Australia. France had the lowest price at $83." (21 August 2023; figures refer to a one-month supply.)

In the US, Wegovy has a list price of $1,349.02 per month as of 2022, suggesting that because of the high costs many people "who could most benefit from weight loss may be unable to afford such expensive drugs". High costs of Ozempic prompted some insurance companies to investigate and refuse to cover patients with what the companies considered was insufficient evidence to support a diabetes diagnosis, alleging off-label prescribing for weight loss.

In the UK, semaglutide is available on NHS prescription for diabetes at nominal or no cost to patients. It is also available for obesity, limited to treatment for two years.

In Finland, semaglutide is included in the national price regulation scheme and is available by prescription; however, for patients with type 2 diabetes and a BMI over 27, part of the cost is covered by Kela—the Finnish Social Insurance Institution.

In the Australia, semaglutide is available on the PBS prescription for diabetes at the regular co-payment rates of $31.60, or $7.70 for concession card holders.

High demand caused worldwide supply shortages of semaglutide in 2023; new UK prescriptions were not issued during the shortage.

Novo Nordisk revealed in April 2024, that to meet the enormous demand for semaglutide, it was running its production facilities 24 hours a day, 365 days per year; it had budgeted $6 billion in 2024 to expand its crowded and congested facilities; and it had hired over 10,000 new employees in 2023 alone.

Economic impact on Danish society

By 2023, Novo Nordisk had become the most valuable corporation in the European Union, worth more than , and accounted for almost all recent economic growth in Denmark.

Profits from Novo Nordisk generate returns for the Novo Nordisk Foundation, which holds the controlling stake in Novo Nordisk. The profits results in increased Danish tax revenues and employment. Novo Nordisk added 3,500 jobs in Denmark in 2022, bringing the total in the country to 21,000 employees, out of 59,000 worldwide.

Counterfeits

In October 2023, there were reports of counterfeit Ozempic pens being sold in Europe. The pens possibly contained insulin, and led to several people being hospitalised with hypoglycemia and seizures. In December 2023, the FDA issued a warning about counterfeit Ozempic in the United States.

Compounded versions

In the United States, compounding pharmacies may prepare compounded versions of a drug on the Food and Drug Administration's (FDA) drug shortages list if the compounded drug meets certain conditions detailed in federal law. The FDA declared a shortage for Ozempic and Wegovy (but not Rybelsus) starting in August 2022.

The US National Association of Boards of Pharmacy claims that there are tens of thousands of online pharmacies operating out of compliance with state and federal regulations or the association's recommendations. Novo Nordisk has taken action against several compounding pharmacies producing bad versions of the drug, with impurities, the wrong amount of active ingredient, or even no active ingredient. Some compounded versions have been found to contain salts of semaglutide including the sodium and the acetate in an attempt to avoid the patent of the base semaglutide product. These are not evaluated for safety and effectiveness by the FDA and thus are considered not shown to be safe or effective.

Research

A 2014 meta-analysis found that semaglutide may be effective in lowering liver enzymes (transaminitis) and improving certain radiologically observed features of metabolic dysfunction–associated steatotic liver disease.
French national health care insurance system database had previously suggested that one to three years of use of glucagon-like peptide-1 receptor agonists like exenatide, liraglutide, and dulaglutide may be linked with increased occurrence of thyroid cancer. Semaglutide belongs to the same family of medicine. A meta-analysis involving data from 37 randomized controlled trials and 19 real-world studies (46,719 patients) showed that semaglutide use over 18 months was not associated with increased risks of any cancer, supported by a high grade of evidence.

In March 2023, a Novo Nordisk official said, based on a randomized, double-blind study (NCT03548935) funded by the company, that patients using semaglutide to lose weight regained two-thirds of their original weight loss one year (52 weeks) after discontinuing use of the drug. After two years (120 weeks), the patients retained roughly one-third of their original weight loss (5.6% of the original 17.3% loss).

In July 2023, the Icelandic Medicines Agency reported two cases of suicidal thoughts and one case of self-injury of users of the injection, prompting a safety assessment of Ozempic, Wegovy, Saxenda, and similar drugs. In January 2024, a preliminary review conducted by the US Food and Drug Administration (FDA) confirmed no evidence had been found to suggest that the medicine causes suicidal thoughts or actions.

Effect on lean body mass

A 2024 systematic review of six studies found that "although reductions in body weight and fat mass were evident, changes in lean mass were minor".

Hair loss

An analysis of FDA reports suggested an association between GLP-1 agonists and alopecia or hair loss. A study, conducted by researchers at the University of British Columbia showed that incidence rates of hair loss were higher in people who took semaglutide than people who took bupropion-naltrexone. Overall, patients who took semaglutide had a 52% higher risk of hair loss than those who took Naltrexone/bupropion, bupropion-naltrexone.

References

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Anti-obesity drugs
GLP-1 receptor agonists
Peptide therapeutics
Peptide hormones
Drugs developed by Novo Nordisk
Experimental drugs developed for non-alcoholic fatty liver disease
Danish inventions
2008 in Denmark
2008 in science
Dicarboxylic acids