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GLP-1

Semaglutide

Prepared by the ezGLP team. Sources last checked . Profile reviewed .

Also known as Ozempic, Wegovy

Routes represented in the knowledgebase: Subcutaneous (SubQ).

Educational overview

Semaglutide is listed in the ezGLP knowledgebase under GLP-1. Evidence and regulatory status can vary by formulation, route, and jurisdiction.

Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist developed by Novo Nordisk and sold as Ozempic and Wegovy for injection and as Rybelsus in tablet form. It is an acylated analogue of the human GLP-1 peptide, sharing about 94 percent of its sequence, with a substitution at position 8 that resists breakdown by the enzyme dipeptidyl peptidase-4 and a fatty diacid side chain that binds albumin. Those modifications extend the circulating half-life to roughly one week. Receptor activation increases glucose-dependent insulin secretion, suppresses glucagon release, slows gastric emptying and acts on hypothalamic and brainstem circuits that regulate appetite and food intake.

The evidence base is unusually large for a metabolic medicine. Novo Nordisk's SUSTAIN programme established glycaemic effects in type 2 diabetes, and SUSTAIN-6, a 3297-participant cardiovascular safety trial published in the New England Journal of Medicine in 2016, reported fewer major adverse cardiovascular events than placebo. The STEP programme addressed obesity: STEP 1 randomised 1961 adults with overweight or obesity and without diabetes for 68 weeks and reported mean weight change of about minus 15 percent against about minus 2 percent on placebo. SELECT, published in 2023, followed 17604 adults with established cardiovascular disease and reported a roughly 20 percent relative reduction in cardiovascular events.

Semaglutide holds separate marketing authorisations by indication and route. In the United States the FDA has approved subcutaneous Ozempic for type 2 diabetes, subcutaneous Wegovy for chronic weight management, and oral Rybelsus tablets for type 2 diabetes; the European Medicines Agency has authorised the same three products centrally across the European Union. The injectable labels carry a boxed warning about thyroid C-cell tumours seen in rodents and list medullary thyroid carcinoma and multiple endocrine neoplasia type 2 as contraindications. Compounded semaglutide is not an FDA-approved product, and the agency has warned about salt forms, dosing errors and material from unregistered sources.

Storage and in-use limits are set by each product label rather than by the molecule. Manufacturer pens are refrigerated before first use and then carry a defined in-use period, after which the label directs disposal; the figures differ between Ozempic, Wegovy and the presentations authorised in other markets, and oral tablets follow different instructions again. Compounded vials instead carry the dispensing pharmacy's beyond-use date. Because the amount per millilitre varies widely between brand pens and compounded multi-dose vials, an inventory record capturing product name, strength, concentration, manufacturer or pharmacy, lot number and first-use date is what makes a later dose log entry interpretable.

Category
GLP-1
Routes represented
Subcutaneous (SubQ)
Approximate library half-life
168 hours; formulation-dependent and not dosing guidance
Storage context
Follow the dispensed product label; storage and in-use limits vary by brand and formulation.

Published literature

Safety evidence

Common or reported: nausea, vomiting, diarrhea, constipation, abdominal pain or indigestion, decreased appetite.

Serious or important: pancreatitis, gallbladder disease, dehydration-related kidney injury, severe GI reactions, hypoglycemia with insulin or secretagogues, hypersensitivity.

Product labels also carry thyroid C-cell tumor warnings.

Safety evidence source

Interaction evidence

These are general, pairwise evidence notes. Green identifies the potential-synergy category, while Lv3/Lv2/Lv1 communicates evidence strength; it does not guarantee benefit or cancel a safety warning.

With insulin or insulin secretagogues

Safety flag

Combined glucose lowering increases hypoglycemia risk, including severe hypoglycemia.

Interaction evidence source

With another GLP-1 receptor agonist

Safety flag

Weight-management labels say coadministration with the same active ingredient or another GLP-1 receptor agonist is not recommended.

Interaction evidence source

With narrow-index or threshold-dependent oral medicines

Safety flag

Delayed gastric emptying can alter the timing or extent of oral-drug absorption.

Interaction evidence source

With Pramlintide

Safety flag

Additive gastric-emptying delay, GI intolerance, and glucose lowering are plausible; a broad clinical contraindication is not established.

Interaction evidence source

Common questions

How long does semaglutide stay in the body?

The elimination half-life is approximately one week, which is why the injectable products are labelled for once-weekly administration. Since roughly five half-lives are needed for near-complete clearance, measurable drug persists for about five weeks after a final injection, and steady-state concentrations are reached after four to five weeks of continued treatment. The long half-life reflects albumin binding and resistance to dipeptidyl peptidase-4.

Is compounded semaglutide the same as Wegovy?

No. Wegovy is an FDA-approved product manufactured to a reviewed specification, while compounded semaglutide is prepared by a pharmacy or outsourcing facility and has not been evaluated by the FDA for safety, effectiveness or quality. The agency has received reports of dosing errors involving compounded vials and syringes, some leading to hospitalisation, and has warned that certain products contain semaglutide salt forms that differ from the approved active ingredient.

How much weight do people lose on semaglutide?

In STEP 1, a 68-week trial of 1961 adults with overweight or obesity and without diabetes, mean body-weight change was about minus 15 percent with semaglutide and about minus 2 percent with placebo, with lifestyle counselling in both groups. Trials in people with type 2 diabetes have generally reported smaller reductions. These figures are group averages from controlled trials, and results among individual participants varied widely.

What are the side effects of semaglutide?

Gastrointestinal effects dominate the labelled adverse-event profile: nausea, vomiting, diarrhoea, constipation and abdominal pain, most frequent while the dose is being escalated. Labels also list gallbladder disease, pancreatitis, acute kidney injury following dehydration, diabetic retinopathy complications in type 2 diabetes, and hypoglycaemia in combination with insulin or a sulfonylurea. A boxed warning describes thyroid C-cell tumours found in rodents; whether the same risk exists in humans is undetermined.

Is semaglutide approved in Europe?

Yes. The European Medicines Agency has authorised semaglutide across the European Union as Ozempic and Rybelsus for type 2 diabetes and as Wegovy for weight management. Because these are centralised authorisations, they apply in every member state. The summaries of product characteristics cover the same thyroid C-cell tumour findings and pancreatitis signals as the United States labels, presented in the EU format rather than as a boxed warning.

Further reading

Tools for your existing schedule

These free calculators use values you supply. They do not recommend Semaglutide, select a dose, or establish a route of administration.

Schedule calendar calculator

Preview and print dose dates and total supply for a schedule, including dose changes you enter yourself.

Supply duration calculator

Estimate how many full doses you have left and when your supply will run out, using your own dose and frequency.

For ongoing records, see ezGLP’s schedule, inventory, and wellness tracking features.

Summarised from published literature for reference only, with citations to the source. Evidence is graded as reported and is not a recommendation to combine, dose, or use any compound.

For personal tracking and education only. Not medical advice, diagnosis, or treatment, and not a medical device. Peptides may be prescription-only or unapproved where you live. Consult a licensed healthcare professional.