Semaglutide

What it is

Semaglutide is a synthetic analogue of glucagon-like peptide-1 (GLP-1), an incretin hormone involved in glucose regulation, appetite signaling, and gastrointestinal physiology. It was developed by Novo Nordisk researchers as a longer-acting GLP-1 receptor agonist, with the design rationale published in 2015 in the Journal of Medicinal Chemistry^{[1 ]}. The molecule was engineered from the GLP-1 peptide backbone to resist enzymatic breakdown and remain in circulation longer than native GLP-1^{[1 –4 ]}.

Chemical structure

Semaglutide is a modified GLP-1 analogue with 94% sequence homology to human GLP-1. It includes amino-acid substitutions and a C18 fatty di-acid modification that increase albumin binding, protect against DPP-4 degradation, and extend its half-life^{[1 –4 ]}.

Mechanism

At the receptor level, semaglutide selectively binds and activates the GLP-1 receptor — the same target as endogenous GLP-1^{[2 –4 ]}. In people with type 2 diabetes, the FDA-approved labels describe glucose lowering through glucose-dependent stimulation of insulin secretion and reduction of glucagon secretion; the labels also note a minor delay in gastric emptying during the early postprandial phase^{[2 –4 ]}. For weight-related effects, the Wegovy label describes semaglutide as reducing excess body weight in approved populations, but the exact clinical contribution of central appetite effects, gastric-emptying effects, and downstream metabolic changes varies by indication^{[3 ]}.

Approved products

Semaglutide is not a single product. In the United States, FDA-approved semaglutide products include:

• Ozempic injection — adults with type 2 diabetes; cardiovascular risk reduction in type 2 diabetes with established cardiovascular disease; kidney-risk reduction in adults with type 2 diabetes and chronic kidney disease^{[2 ]}.
• Wegovy injection — chronic weight management; cardiovascular risk reduction in adults with established cardiovascular disease and obesity or overweight; noncirrhotic MASH with F2–F3 fibrosis under accelerated approval^{[3 ]}.
• Wegovy tablets — adult weight management; cardiovascular risk reduction in adults with established cardiovascular disease and obesity or overweight^{[3 ]}.
• Rybelsus and Ozempic tablets — oral semaglutide for adults with type 2 diabetes; cardiovascular risk reduction in adults with type 2 diabetes who are at high risk for cardiovascular events^{[4 ]}.

Administration

When used clinically, semaglutide is administered either by subcutaneous injection or as an oral tablet, depending on the branded product and indication^{[2 –4 ]}. Oral semaglutide formulations use salcaprozate sodium (SNAC) to support gastrointestinal absorption of the peptide^{[4 ]}. These details describe approved product forms and are not dosing guidance.

Regulatory status

Semaglutide is FDA-approved as a prescription drug in multiple branded products. Ozempic injection is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes, to reduce major adverse cardiovascular events in adults with type 2 diabetes and established cardiovascular disease, and to reduce sustained eGFR decline, end-stage kidney disease, and cardiovascular death in adults with type 2 diabetes and chronic kidney disease^{[2 ]}. Wegovy injection is indicated for chronic weight management in adults and adolescents 12 years and older meeting label criteria, cardiovascular risk reduction in adults with established cardiovascular disease and obesity or overweight, and noncirrhotic MASH with F2–F3 fibrosis in adults under accelerated approval^{[3 ,9 ]}. Wegovy HD, a 7.2 mg injection strength, was approved by FDA on March 19, 2026 for weight loss and long-term maintenance of weight loss in certain adults^{[22 ]}. Rybelsus and Ozempic tablets are approved for adults with type 2 diabetes and for major cardiovascular event risk reduction in adults with type 2 diabetes who are at high cardiovascular risk^{[4 ]}.

Compounding policy

Compounding status changed substantially after the semaglutide shortage resolved. FDA announced on February 21, 2025 that the semaglutide injection product shortage was resolved, with enforcement-discretion periods ending April 22, 2025 for 503A state-licensed pharmacies and physicians and May 22, 2025 for 503B outsourcing facilities compounding semaglutide injection products based on the shortage-list status^{[5 ]}. FDA’s April 1, 2026 update states that semaglutide and tirzepatide do not currently appear on the FDA drug shortage list or the 503B bulks list^{[5 ]}. On April 30, 2026, FDA proposed excluding semaglutide, tirzepatide, and liraglutide from the 503B bulks list after finding no clinical need for outsourcing facilities to compound these drugs from bulk substances^{[6 ]}.

For 503A pharmacy compounding, FDA policy restricts regular or inordinate compounding of products that are essentially copies of commercially available drugs^{[5 ]}. For 503B outsourcing facilities, FDA states that bulk-drug compounding generally requires the substance to appear on the 503B bulks list or the drug to be on the shortage list at the time of compounding, distribution, and dispensing^{[5 –6 ]}. FDA has also warned that semaglutide sodium and semaglutide acetate are different active ingredients from the base form used in approved products, and that FDA is not aware of a lawful basis for compounding semaglutide salt forms under the cited conditions^{[7 ]}.

Controlled-substance status

Semaglutide is not listed in federal controlled-substance schedules in 21 CFR Part 1308, and FDA-approved semaglutide labels do not identify it as a controlled substance^{[2 –4 ,8 ]}. International approvals differ by jurisdiction and product; this page is focused on United States regulatory status. Last regulatory verification: May 4, 2026.

Research summary

Semaglutide has one of the larger clinical evidence bases among peptide-based metabolic drugs.

Type 2 diabetes and cardiovascular outcomes

In type 2 diabetes, SUSTAIN-6 randomized 3,297 patients with type 2 diabetes at high cardiovascular risk to once-weekly injectable semaglutide or placebo for 104 weeks; the trial showed cardiovascular noninferiority and fewer major adverse cardiovascular events with semaglutide, while diabetic retinopathy complications were more frequent in the semaglutide group^{[10 ]}. For oral semaglutide, PIONEER-6 established cardiovascular safety in 3,183 people with type 2 diabetes and high cardiovascular risk^{[11 ]}. The later SOUL trial randomized 9,650 participants with type 2 diabetes and atherosclerotic cardiovascular disease, chronic kidney disease, or both; oral semaglutide was associated with a lower risk of major adverse cardiovascular events than placebo, with a hazard ratio of 0.86 and no increase in serious adverse events^{[12 ]}.

Chronic weight management

For chronic weight management, the STEP program provides the central clinical-trial evidence. STEP 1 randomized 1,961 adults with obesity or overweight without diabetes to semaglutide 2.4 mg or placebo for 68 weeks with lifestyle intervention; mean body-weight change was −14.9% with semaglutide and −2.4% with placebo^{[13 ]}. STEP 2 studied adults with overweight or obesity and type 2 diabetes and found greater weight reduction with semaglutide 2.4 mg than placebo^{[14 ]}. STEP 4 examined withdrawal after a semaglutide run-in period and found that continued treatment was associated with additional weight loss while switching to placebo was associated with weight regain, indicating that discontinuation commonly reverses some treatment-associated weight change^{[15 ]}. STEP TEENS studied adolescents with obesity and found a larger BMI reduction with semaglutide than placebo, with cholelithiasis reported in 4% of semaglutide-treated participants and none in the placebo group^{[16 ]}.

Cardiovascular outcomes in obesity without diabetes

Cardiovascular outcomes in obesity without diabetes were tested in SELECT, which randomized 17,604 adults with established cardiovascular disease and overweight or obesity but no diabetes. Semaglutide reduced the composite outcome of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke, with a hazard ratio of 0.80 compared with placebo^{[17 ]}. This trial supported FDA’s 2024 cardiovascular risk-reduction indication for Wegovy in adults with cardiovascular disease and overweight or obesity^{[3 ,17 ]}.

Chronic kidney disease

Kidney outcomes were evaluated in FLOW, a randomized trial of 3,533 participants with type 2 diabetes and chronic kidney disease. The primary composite kidney and cardiovascular death outcome occurred less often with semaglutide than placebo, with a hazard ratio of 0.76; the trial was stopped early after a prespecified interim analysis^{[18 ]}. FDA subsequently added a kidney-risk reduction indication to Ozempic for adults with type 2 diabetes and chronic kidney disease^{[2 ]}.

MASH (formerly NASH)

Liver-disease research has progressed from NASH to MASH terminology. A 2021 phase 2 trial in biopsy-confirmed NASH found higher NASH resolution with semaglutide than placebo, but the fibrosis-improvement endpoint did not show a statistically significant difference^{[19 ]}. In the phase 3 ESSENCE trial, 1,197 patients with biopsy-defined MASH and F2–F3 fibrosis were assigned to semaglutide 2.4 mg or placebo; the week-72 interim analysis of the first 800 patients found MASH resolution without fibrosis worsening in 62.9% versus 34.3%, and fibrosis reduction without MASH worsening in 36.8% versus 22.4%^{[20 ]}. FDA’s MASH approval for Wegovy is accelerated approval, meaning continued approval may depend on verification of clinical benefit in the ongoing confirmatory portion of the trial^{[3 ,9 ,20 ]}.

Newer formulations and strengths

Newer formulations and strengths are still evolving. Oral semaglutide 25 mg for obesity was studied in OASIS 4, a 64-week phase 3 trial in adults with overweight or obesity; the trial publication reported clinically meaningful weight loss and supported the approval of Wegovy tablets for weight management^{[21 ]}. FDA approved Wegovy HD, a higher-dose 7.2 mg semaglutide injection, on March 19, 2026 based on clinical data showing additional average weight reduction compared with previously approved Wegovy doses, while noting gastrointestinal adverse reactions and more frequent altered skin sensation at the higher dose^{[22 ]}.

Where the evidence ends

Overall, the evidence is strongest for FDA-approved indications: type 2 diabetes glycemic control, chronic weight management in label-defined populations, cardiovascular risk reduction in specific high-risk groups, kidney-risk reduction in type 2 diabetes with chronic kidney disease, and MASH with F2–F3 fibrosis under accelerated approval. Evidence should not be generalized to unapproved uses such as nonspecific “longevity,” cosmetic body-composition optimization, or use in people who do not meet trial-like clinical criteria.

Public discourse

Peter Attia, MD, on The Drive, has covered semaglutide and GLP-1 agonists across multiple episodes. Early on, he discussed GLP-1 physiology, semaglutide’s STEP 1 weight-loss data, and the possibility that GLP-1 drugs could become important obesity treatments while requiring careful discussion of risks and long-term use^{[24 ]}.

In a 2024 follow-up, Attia revisited semaglutide and related GLP-1 drugs with emphasis on efficacy, discontinuation, body composition, protein intake, and resistance training in people using these medicines^{[25 ]}.

Mark Hyman, MD, on The Dr. Hyman Show, framed Ozempic and Wegovy as important but incomplete tools, emphasizing cost, shortages, adverse effects, and the broader food-system drivers of obesity^{[26 ]}.

Rhonda Patrick, PhD, on a PBD Podcast appearance summarized in third-party reporting, discussed GLP-1 drugs in the context of lifestyle, genetics, and public narratives around obesity. The summary should be treated as public commentary rather than clinical guidance, and a primary transcript should replace this source before publication^{[27 ]}.

Public discourse reflects the views of the speakers cited and does not represent medical advice or the editorial position of ProPeptideGuide.

Side effects and safety

The FDA-approved labels for semaglutide products carry a boxed warning for thyroid C-cell tumors observed in rodents; the human relevance is unknown, and the products are contraindicated in patients with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2^{[2 –4 ]}. Labels also describe contraindication in patients with known serious hypersensitivity to semaglutide or product excipients^{[2 –4 ]}.

Common adverse reactions

Common adverse reactions are primarily gastrointestinal. The Ozempic label lists nausea, vomiting, diarrhea, abdominal pain, and constipation as common adverse reactions^{[2 ]}. The Wegovy label lists nausea, diarrhea, vomiting, constipation, abdominal pain, dysesthesia, headache, fatigue, dyspepsia, dizziness, abdominal distension, eructation, hypoglycemia in patients with type 2 diabetes, flatulence, gastroenteritis, gastroesophageal reflux disease, and hair loss among common reactions^{[3 ]}. Rybelsus and Ozempic tablets list nausea, abdominal pain, diarrhea, decreased appetite, vomiting, and constipation among common reactions^{[4 ]}.

Important warnings

Important warnings include acute pancreatitis, acute gallbladder disease, hypoglycemia when combined with insulin or insulin secretagogues, acute kidney injury due to volume depletion, severe gastrointestinal adverse reactions, hypersensitivity reactions, diabetic retinopathy complications in patients with type 2 diabetes, heart-rate increase for Wegovy, and pulmonary aspiration during general anesthesia or deep sedation^{[2 –4 ]}. In SUSTAIN-6, diabetic retinopathy complications were reported more often with semaglutide than placebo, particularly among patients with a history of diabetic retinopathy^{[2 ,10 ]}.

Drug interactions

Drug-interaction concerns are mostly related to gastric emptying and combination therapy. FDA labels state that semaglutide delays gastric emptying and may affect absorption of concomitantly administered oral medications, especially those requiring clinical monitoring or with narrow therapeutic index^{[2 –4 ]}. Labels also warn that use with insulin or insulin secretagogues may increase hypoglycemia risk^{[2 –4 ]}.

Long-term safety

Long-term safety data are more substantial than for many peptide products because semaglutide has multi-year cardiovascular and kidney outcome trials, including SELECT and FLOW^{[17 –18 ]}. However, decades-long data for obesity, MASH, higher-dose Wegovy HD, and newer oral weight-management formulations remain limited because those indications and formulations are newer^{[3 ,20 –22 ]}.

Available through

FDA-approved semaglutide is available in the United States by prescription through licensed clinicians and pharmacies dispensing approved branded products such as Ozempic, Wegovy, Wegovy HD, Rybelsus, and approved tablet formulations, when used within the relevant label and prescribing rules^{[2 –4 ,22 ]}.

Provider-platform listings will be added only after legal and editorial verification that the platform prescribes FDA-approved semaglutide products through licensed clinicians and dispenses through state-licensed pharmacies or other compliant pharmacy channels. ProPeptideGuide does not link to or endorse gray-market vendors, research-chemical sites, semaglutide salt products, or compounded products marketed as generics or copies of FDA-approved semaglutide products^{[5 –7 ]}.