Semaglutide is a modified peptide that activates the receptor for glucagon-like peptide-1, a hormone released after food enters the gut. Its clinical development began with glucose control and expanded into weight management, cardiovascular events, kidney disease and liver disease. Large randomized trials now support several of those uses, while oral and injectable products retain different approved indications. Understanding the research therefore starts with the formulation and the population studied: an obesity trial, a kidney trial in diabetes and a liver-biopsy trial answer different questions.
Overview
Molecular profile
- Type
- Modified GLP-1 peptide analogue; 31 amino acids Source
- Chemical form
- Semaglutide active peptide in approved formulations; proposed sodium and acetate salts are recorded separately Source
- Molecular formula
- C187H291N45O59 (semaglutide active peptide) Source
- Molecular weight
- 4113.58 g/mol (semaglutide active peptide) Source
- Structural modifications
- DPP-4-resistant residue substitution and a C18 (18-carbon) fatty-diacid attachment through a spacer at Lys26 Source
- Primary target
- GLP-1 receptor Source
Forms and derivatives
Injectable semaglutide: Wegovy and Ozempic
Wegovy and Ozempic contain semaglutide in approved injection formulations. The current Wegovy presentation list includes Wegovy HD in the adult weight-management context, with separate indication-specific exposure information in the label.
Oral semaglutide: Wegovy, Rybelsus and Ozempic tablets
Tablets use an absorption enhancer to deliver semaglutide through the stomach. The 2026 labels separate the adult weight-management tablet from the adult diabetes tablet products.
Semaglutide sodium and semaglutide acetate
FDA identifies these salts as different active ingredients from the ingredient in approved semaglutide medicines and reports insufficient information establishing equivalent chemical and pharmacological properties.
Cagrilintide–semaglutide combination (CagriSema)
Clinical studies coadminister cagrilintide, an amylin analogue, with semaglutide. Combination outcomes are attributed to the studied preparation and compared with its actual trial arms.
The active peptide resembles human GLP-1, with changes that protect it from an enzyme called DPP-4 and a fatty-acid side chain that encourages binding to albumin, the abundant transport protein in blood. Albumin binding helps keep the peptide in circulation. Lau and colleagues (2015) describe how the researchers balanced that longer persistence with the molecule's ability to activate the GLP-1 receptor. This chemistry underlies the prolonged human exposure later characterized in clinical studies.
Approved products contain semaglutide in specified pharmaceutical formulations. The FDA identifies semaglutide sodium and semaglutide acetate as different active ingredients and says it lacks information establishing the same chemical and pharmacological properties as the ingredient in approved medicines. The parent peptide, its proposed salt forms and a product containing an added ingredient therefore need distinct identity records. FDA's current account of unapproved GLP-1 products explains that distinction.
Uses and research areas
The June 2026 Wegovy label gives the injection weight-management indications for adults and adolescents aged 12 years or older with obesity, and adults with overweight plus a weight-related condition. It also covers cardiovascular risk reduction in adults with established cardiovascular disease and overweight or obesity, and treatment of noncirrhotic metabolic dysfunction-associated steatohepatitis (MASH) in adults. MASH is a fatty-liver disease with inflammation; the approved population has moderate-to-advanced scarring, classified as F2–F3 fibrosis. The liver indication uses accelerated approval based on biopsy improvement; longer-term clinical benefit requires confirmation. Wegovy tablets have adult weight-management and cardiovascular indications. The adolescent and MASH indications apply to the injection. The newer higher-strength Wegovy HD presentation appears in the adult weight-management context.
The diabetes formulations have their own scope. Ozempic injection is approved for adult type 2 diabetes, cardiovascular risk reduction with established cardiovascular disease, and specified kidney outcomes in adults with both type 2 diabetes and chronic kidney disease. The January 2026 Rybelsus and Ozempic tablet label covers adult type 2 diabetes and cardiovascular risk reduction in adults with type 2 diabetes at high cardiovascular risk.
Mechanism of action
After a meal, GLP-1 helps coordinate the pancreas, digestive tract and brain. In the pancreas's insulin-producing beta cells, receptor activation strengthens the signal for insulin secretion when glucose is elevated. Semaglutide also reduces glucagon secretion; glucagon normally tells the liver to release glucose. Together, these changes reduce the amount of glucose entering the bloodstream and improve its disposal. Concurrent insulin therapy supplies additional insulin, while sulfonylureas stimulate its release; either can increase the risk of hypoglycemia when used with semaglutide. These actions are described in section 12.1 of the Ozempic prescribing information.
The weight effect involves appetite regulation and lower energy intake. GLP-1 receptors occur in brain regions involved in eating, while slower gastric emptying changes how quickly nutrients move out of the stomach. Those effects connect a gut-hormone signal to fullness and food intake. Cardiovascular, kidney and liver outcomes then reflect the integrated response over months or years. A clinical endpoint trial establishes whether events changed under treatment; it does not assign the whole effect to one receptor-bearing tissue. Sections 12.1–12.2 of the FDA Wegovy label describe this pharmacology.
Pharmacokinetics
Semaglutide persists after absorption because the modified peptide resists rapid degradation and binds extensively to albumin. The FDA Wegovy label, section 12.3, reports an elimination half-life of approximately one week. The peptide is broken down through cleavage of its backbone and metabolism of its fatty-acid side chain. Elimination is therefore a gradual process even after administration has stopped.
The route changes the absorption stage. Injection provides high systemic bioavailability and reaches its maximum concentration over days. Tablets combine semaglutide with an absorption enhancer, SNAC, to allow uptake predominantly through the stomach; only a small fraction of the oral amount enters circulation. The current oral semaglutide label, section 12.3 explains this formulation dependence. Oral and injectable milligram amounts therefore represent different delivery systems, even though the circulating active peptide has prolonged elimination.
Population: People with overweight or obesity characterized in the semaglutide prescribing information. Administration: subcutaneous administration; illustration begins in the post-absorption elimination phase. Analyte: circulating semaglutide parent peptide.
This calculated line illustrates semaglutide elimination in people with overweight or obesity after injection under the skin. The label reports an approximate one-week half-life: in this model, a starting concentration set to 100% falls to 50% after seven days. These percentages illustrate elimination rather than measured blood concentrations. The model applies C/C0 = 2^(-t/t_half) after absorption, assumes a constant half-life and tracks only the parent peptide. The vertical scale expresses a percentage of an arbitrary starting concentration. It supplies no measured concentration, absorption peak, repeated-treatment accumulation or schedule for use.
Novo Nordisk; US Food and Drug Administration. WEGOVY (semaglutide) injection and tablets: approved prescribing information. Revised June 2026. NDA 218316 supplement 007. FDA WEGOVY label, section 12.3, Elimination: approximately one-week human half-life.
The illustration begins at an arbitrary normalized concentration after absorption and applies the one-week half-life to that elimination phase. It helps show why exposure falls gradually. Actual blood concentrations also depend on absorption, repeated administration and individual variability; the figure supplies no measured peak or full concentration-time profile.
Research findings
Weight loss, tablets and withdrawal
Wilding and colleagues' STEP 1 trial (2021) randomized 1,961 adults with overweight or obesity without diabetes to injectable semaglutide or placebo, alongside lifestyle intervention. At 68 weeks, mean weight change was −14.9% and −2.4%, respectively. The analysis estimated the effect of assignment to treatment, including participants who stopped the trial product. Gastrointestinal events caused discontinuation in 4.5% versus 0.8%, making persistence with treatment part of the interpretation of the average benefit.
The STEP 1 extension reported by Wilding and colleagues (2022) followed a selected group of 327 participants after medication and structured lifestyle support ended. The former semaglutide group regained 11.6 percentage points during the following year after a 17.3% loss in that subset, leaving a 5.6% mean reduction from original weight. Because both forms of support ended and the extension selected completers, it describes that withdrawal context. The result explains why maintenance has become a central clinical question.
Oral weight-management evidence includes Wharton and colleagues' OASIS 4 trial (2025). In 307 adults without diabetes, the tested tablet formulation produced a mean weight change of −13.6% at week 64, compared with −2.2% with placebo. Gastrointestinal adverse events occurred in 74.0% and 42.2%. The 71-week trial included lifestyle support and used week 64 for its principal weight assessment, a detail that matters when comparing follow-up periods.
Cardiovascular, kidney and liver outcomes
Lincoff and colleagues' SELECT trial (2023) studied 17,604 adults with established cardiovascular disease, overweight or obesity, and no diabetes. Cardiovascular death, nonfatal myocardial infarction or nonfatal stroke occurred in 6.5% with semaglutide and 8.0% with placebo over a mean 39.8-month follow-up; the hazard ratio was 0.80. The observed event proportions differed by 1.5 percentage points. This provides a clinical-event result in a population already at cardiovascular risk.
Perkovic and colleagues' FLOW trial (2024) randomized 3,533 people with type 2 diabetes and chronic kidney disease to semaglutide or placebo. The investigators tracked worsening kidney disease and deaths from kidney or cardiovascular causes as one combined outcome. It occurred in 331 participants given semaglutide and 410 given placebo over a median 3.4 years, giving a hazard ratio of 0.76. Because cardiovascular death counted in this outcome, the result combines kidney progression with survival rather than measuring kidney function alone.
The oral SOUL programme tested semaglutide tablets against placebo. McGuire and colleagues (2025) studied 9,650 participants with type 2 diabetes and cardiovascular disease, kidney disease or both. Major cardiovascular events occurred in 12.0% with semaglutide and 13.8% with placebo, hazard ratio 0.86. A prespecified analysis of the same trial asked about a five-component outcome combining kidney events with cardiovascular death. Mann and colleagues (2026) reported this outcome in 8.4% with semaglutide and 9.0% with placebo, hazard ratio 0.91 with a 95% confidence interval of 0.80–1.05. The kidneys' ability to filter blood declined more slowly with semaglutide. Although the combined events were numerically less frequent, that comparison was too uncertain to establish a reduction. Differences in starting kidney function, formulation and the events counted distinguish SOUL from FLOW.
In Sanyal and colleagues' ESSENCE interim analysis (2025), the first 800 assessed participants had biopsy-defined MASH with F2–F3 fibrosis. At 72 weeks, steatohepatitis resolved without worsening fibrosis in 62.9% with semaglutide and 34.3% with placebo. Fibrosis improved without worsening steatohepatitis in 36.8% and 22.4%. Biopsies document changes in inflammation and scarring; continued follow-up addresses whether those changes prevent later liver complications.
Direct comparisons and combination research
Aronne and colleagues' SURMOUNT-5 trial (2025) directly compared tirzepatide with injectable semaglutide in adults with obesity without type 2 diabetes. Among 751 randomized participants, mean weight reductions at 72 weeks were 20.2% and 13.7%. The open-label trial used specified tolerated protocol exposures, giving a stronger basis for that comparison than comparing percentages from separate trials.
Combination studies add another hormone pathway. Frias and colleagues (2023) studied cagrilintide plus semaglutide and each component alone in 92 adults with type 2 diabetes. At 32 weeks, weight changes were −15.6%, −5.1% with semaglutide and −8.1% with cagrilintide. HbA1c, the marker of average blood glucose, fell more with the combination than with semaglutide alone, but the between-group difference remained uncertain and did not meet the trial’s threshold for statistical significance. Garvey and colleagues' REDEFINE 1 trial (2025) subsequently enrolled 3,417 adults without diabetes and found mean weight change of −20.4% with the combination versus −3.0% with placebo under the treatment-policy analysis. CagriSema's results belong to that coadministered preparation and its study design.
Safety and tolerability
Nausea, vomiting, diarrhea, constipation and abdominal discomfort are common across approved semaglutide products. More serious concerns include pancreatitis, gallbladder disease, dehydration-associated kidney injury and severe gastrointestinal symptoms. Delayed stomach emptying matters around anesthesia because retained gastric contents can be aspirated. Diabetic retinopathy requires attention in patients with a history of the condition, especially as glucose control improves. Insulin and insulin-secretagogue combinations increase hypoglycemia risk. These warnings appear in the current Ozempic injection label.
The boxed warning concerns thyroid C-cell tumors found in rodents, with uncertain relevance to humans. Approved semaglutide products are contraindicated with personal or family medullary thyroid carcinoma, multiple endocrine neoplasia type 2 (MEN2) or serious hypersensitivity. Pregnancy considerations depend on indication, and tablets also have a breastfeeding restriction. The June 2026 Wegovy label also reports altered skin sensation, called dysesthesia, more often in the higher-strength injection programme. Safety interpretation therefore includes the presentation and exposure studied. FDA's warnings about unapproved products additionally concern ingredient identity, preparation quality and medication errors; trial safety estimates describe the studied medicines.
What the research means
Semaglutide has evidence spanning weight, glucose regulation and several clinical outcomes. Its strongest conclusions arise from trials that define the population and measure an outcome relevant to that population: SELECT for cardiovascular events without diabetes, FLOW for kidney disease with diabetes, and ESSENCE for liver histology. The variation between those endpoints helps explain why one approved indication cannot simply be transferred to every semaglutide product.
The research also makes maintenance, tolerability and the delivery system part of the benefit. Average weight reduction changes when a study counts treatment discontinuation differently, and the withdrawal extension shows that the biological drivers of obesity remain after treatment ends. Interpreting an advertised percentage requires the comparator, follow-up period and analysis method, alongside the active ingredient's name.
FAQs
Do all semaglutide products have the same approved uses?
The current US labels separate injection and tablet indications. Wegovy's adolescent obesity and adult MASH indications apply to the injection; its tablet indications are for adults. Diabetes products have their own cardiovascular and kidney scope. The formulation-specific uses are described above with links to the current labels.
What happened when semaglutide treatment stopped in STEP 1?
In the selected extension population, much of the earlier loss returned during the following year, while mean weight remained below its original level. Medication and structured lifestyle support ended together, so the study describes withdrawal of that combined support. Wilding and colleagues (2022) explain the extension design.
Why did FLOW and the oral SOUL kidney analysis reach different conclusions?
FLOW enrolled people with established diabetic kidney disease and tested injected semaglutide against placebo. SOUL enrolled a broader population with type 2 diabetes and cardiovascular disease, kidney disease or both, and compared semaglutide tablets with placebo. In SOUL, the kidneys' ability to filter blood declined more slowly with semaglutide. The combined kidney and cardiovascular-death events were also numerically less frequent, but the difference was too uncertain to establish a reduction. These differences in population, formulation and the events counted help explain the results in Mann and colleagues (2026).
Does the elimination figure show measured blood concentrations?
The curve is computed from an approximate human half-life and an arbitrary starting concentration. It shows how a constant half-life produces a gradual decline after absorption. A measured concentration-time curve would also need original blood samples, their time points and the absorption phase.
Comparisons and related reading
Tirzepatide engages both GIP and GLP-1 receptors, while liraglutide is an earlier GLP-1 analogue with shorter persistence. Pramlintide and cagrilintide belong to the amylin pathway, which helps explain the rationale for combining cagrilintide with semaglutide. The direct SURMOUNT-5 comparison and the CagriSema trials each answer a defined comparison; their designs and outcome analyses determine how far the results travel.
References
The current label separates adult tablet indications from injection indications, including adolescent obesity and accelerated approval for adult MASH with F2–F3 fibrosis.
The FDA label supplies mechanism and human elimination information for the semaglutide illustration, with the current manufacturer DailyMed listing independently checked.
The injection label defines adult diabetes, cardiovascular and diabetes-associated kidney indications and the pancreatic mechanism and safety warnings.
The oral diabetes label identifies both brands, adult glucose and cardiovascular indications, and formulation-dependent absorption with SNAC.
The agency explains concerns about unapproved preparations and identifies semaglutide sodium and acetate as different active ingredients from approved semaglutide.
The discovery experiments explain how peptide substitutions and albumin affinity were balanced with GLP-1 receptor activity.
The oral weight-management trial distinguishes the 71-week study duration from its week-64 primary weight assessment.
The main oral SOUL paper supplies the cardiovascular-event result alongside the separately retained kidney analysis of the same cohort.
STEP 1 establishes injectable semaglutide's average weight effect alongside lifestyle intervention and records gastrointestinal discontinuation.
SELECT measures clinical cardiovascular events in adults with established disease and overweight or obesity who did not have diabetes.
FLOW measures kidney progression and kidney or cardiovascular death in people with diabetic chronic kidney disease.
The selected STEP 1 extension follows weight after both medication and structured lifestyle support were withdrawn.
In the oral SOUL trial, kidney filtration declined more slowly with semaglutide than with placebo. Combined kidney and cardiovascular-death events were numerically less frequent, but the difference was too uncertain to establish a reduction.
ESSENCE's planned interim analysis provides biopsy outcomes in MASH with F2–F3 fibrosis while longer clinical follow-up continues.
SURMOUNT-5 directly compares tirzepatide and semaglutide weight outcomes under the same open-label randomized protocol.
The phase 2 coadministration study includes separate component arms and shows that the weight and HbA1c comparisons reached different conclusions.
REDEFINE 1 evaluates the cagrilintide–semaglutide combination with placebo and monotherapy arms, using a treatment-policy estimate.
The October 2025 injection label provides the earlier pharmacology and safety context; the current June 2026 label supplies the article’s current indication and formulation information.
Glossary
- GLP-1
- Glucagon-like peptide-1, a gut hormone that coordinates meal-related glucose regulation and appetite.
- DPP-4
- An enzyme that rapidly cleaves native GLP-1; semaglutide has a protective structural modification.
- Albumin
- An abundant blood protein that binds semaglutide and helps prolong circulating exposure.
- Bioavailability
- The fraction of an administered substance that reaches systemic circulation.
- MASH
- Metabolic dysfunction-associated steatohepatitis: liver inflammation and injury associated with metabolic dysfunction and fat accumulation.
- Fibrosis
- Accumulation of scar tissue; F2–F3 identifies the moderate-to-advanced stages studied for the approved MASH use.
- Hazard ratio
- A trial comparison of event occurrence over time; it differs from the absolute difference in observed event percentages.
- Treatment-policy analysis
- An estimate of the effect of treatment assignment that accounts for participants who discontinue or use additional treatment.