Semaglutide is a GLP-1 receptor agonist given once a week by injection or once a day by mouth, approved by the FDA for type 2 diabetes and chronic weight management. It has been tested in large randomised trials, including heart, kidney and liver outcome studies.
Approved drug exists
Human trials
Also known as Ozempic, Wegovy, Rybelsus
Written by Upzo editorial team
Legal status
FDA-approved as prescription drugs (Ozempic and Rybelsus for type 2 diabetes, Wegovy for chronic weight management).
Checked on Oct 26, 2026
Example vials
5 mg · 10 mg
5 mg + 2 mL
2,500 mcg/mL
Per U-100 unit
25 mcg
Studies in library
16
01
What is Semaglutide?
Semaglutide is a modified version of GLP-1, a hormone the gut releases after eating. Natural GLP-1 lasts only minutes in the blood; semaglutide was altered so that its half-life is about one week (Marso 2016), which allows once-weekly injection. Like GLP-1, it increases insulin release when blood sugar is high, slows stomach emptying and reduces appetite.
It was developed by the Danish company Novo Nordisk. The FDA approved it as a weekly injection for type 2 diabetes (Ozempic) in 2017, as a daily tablet for type 2 diabetes (Rybelsus) in 2019 and at a higher weekly dose for chronic weight management (Wegovy) in 2021. Almost all of the large trials described below were run and funded by Novo Nordisk.
Unlike most peptides on this site, semaglutide has tens of thousands of trial participants behind it, so its evidence is mainly human. Products sold online as "research semaglutide" and compounded versions are not the same thing as the approved drugs: they have not been reviewed by the FDA for safety, effectiveness or quality.
Type: modified GLP-1 analogue (peptide with a fatty acid side chain).
Studied for: type 2 diabetes, obesity, heart and kidney outcomes, fatty liver disease.
Strongest evidence: large randomised, placebo-controlled phase 3 trials in people.
Legal status: FDA-approved prescription medicine (Ozempic, Rybelsus, Wegovy).
02
Semaglutide dosing in the FDA label
The approved drug has an official dosing schedule in its FDA label. It is shown here as published, with its source.
Dosing from the current FDA-approved label of each drug.
Drug
Approved use
Dosing in the label
Ozempic (injection)
Type 2 diabetes in adults; also to lower kidney and heart risk in adults with type 2 diabetes and kidney disease
0.25 mg once weekly for 4 weeks (a starting step, not effective for blood sugar), then 0.5 mg once weekly. If needed, 1 mg after at least 4 weeks, then 2 mg after at least 4 more weeks. Maximum 2 mg once weekly.
Rybelsus (tablet)
Type 2 diabetes in adults
3 mg once daily for 30 days, then 7 mg once daily. From day 61, 14 mg once daily if more glucose control is needed.
Ozempic (tablet)
Type 2 diabetes in adults
1.5 mg once daily for 30 days, then 4 mg once daily. From day 61, 9 mg once daily if more glucose control is needed. Not interchangeable mg for mg with Rybelsus.
Wegovy (injection)
Weight reduction (adults and children 12+), heart risk reduction, and MASH with liver fibrosis
0.25 mg once weekly in weeks 1 to 4, 0.5 mg in weeks 5 to 8, 1 mg in weeks 9 to 12, 1.7 mg in weeks 13 to 16, then 2.4 mg (or 1.7 mg) once weekly. For adult weight reduction, up to 7.2 mg once weekly after at least 4 weeks on 2.4 mg.
Wegovy (tablet)
Weight reduction and heart risk reduction in adults
1.5 mg once daily on days 1 to 30, 4 mg on days 31 to 60, 9 mg on days 61 to 90, then 25 mg once daily.
Schedules reported for this peptide, with the syringe measure for each step and the supplies each one takes. Reported use is not evidence that a schedule works or is safe, and none of this is medical advice.
Once-weekly escalation
Subcutaneous injection, once a week
From the FDA label
The escalation in the FDA label of the approved drug, worked out for a research vial. Worked out with a 10 mg vial + 3 mL bacteriostatic water (3.33 mg/mL, 33.3 mcg per unit).
Amounts as reported, with the syringe or spray measure for the vial below. Not a recommendation.
Period
Amount each time
U-100 units
Volume
Weeks 1-4
250 mcg
7.5
0.08 mL
Weeks 5-8
500 mcg
15
0.15 mL
Weeks 9-12
1 mg
30
0.3 mL
Weeks 13-16
1.7 mg
51
0.51 mL
Week 17 on
2.4 mg
72
0.72 mL
Minimum supplies, worked out from the amounts above. Add a margin for losses.
Item
12 weeks
24 weeks
Injections
12
24
Total peptide
7 mg
33 mg
Semaglutide vials (10 mg)
1
4
Bacteriostatic water
3 mL
12 mL
Water bottles (10 mL)
1
2
U-100 insulin syringes
12
24
Alcohol swabs (boxes of 100)
24 (1)
48 (1)
04
Semaglutide doses used in studies
The dose each published study gave its participants, copied from the paper. Not dosing instructions; animal doses do not convert directly to people.
At a glance: 15 studies report a dose (15 in people).
Doses used in human studies
Wilding JPH 2021: 2.4 mg once weekly, reached by gradual escalation (Subcutaneous, once weekly; 68 weeks)
Frías JP 2021: Tirzepatide 5 mg, 10 mg or 15 mg once weekly vs semaglutide 1 mg once weekly (Subcutaneous, once weekly; 40 weeks)
Aronne LJ 2025: Maximum tolerated dose of tirzepatide (10 mg or 15 mg) vs semaglutide (1.7 mg or 2.4 mg) once weekly (Subcutaneous, once weekly; 72 weeks)
Sorli C 2017: 0.5 mg or 1.0 mg once weekly (Subcutaneous, once weekly; 30 weeks)
Marso SP 2016: 0.5 mg or 1.0 mg once weekly (Subcutaneous, once weekly; 104 weeks)
Davies M 2021: 2.4 mg or 1.0 mg once weekly (Subcutaneous, once weekly; 68 weeks)
Rubino D 2021: 2.4 mg once weekly, reached during a 20-week run-in (Subcutaneous, once weekly; 20-week run-in, then 48 weeks randomised)
Wilding JPH 2022: 2.4 mg once weekly for 68 weeks, then no treatment (Subcutaneous, once weekly (then stopped); 68 weeks on treatment plus 52 weeks off treatment)
Lincoff AM 2023: 2.4 mg once weekly (Subcutaneous, once weekly; Mean follow-up 39.8 months)
Perkovic V 2024: 1.0 mg once weekly (Subcutaneous, once weekly; Median follow-up 3.4 years (stopped early for benefit))
Sanyal AJ 2025: 2.4 mg once weekly (Subcutaneous, once weekly; 72-week interim analysis of a planned 240-week trial)
Every study
Doses as reported by each study. Not a recommendation.
What has been studied, by type of evidence. A result in animals or cells is a reason to study something in people, not proof that it works in people.
In humans
Summarised
Weight
STEP 1: adults with obesity or overweight and no diabetes lost a mean 14.9% of body weight over 68 weeks on 2.4 mg weekly, against 2.4% on placebo (Wilding 2021).
STEP 2: in adults with obesity and type 2 diabetes, weight loss was smaller: 9.6% vs 3.4% on placebo (Davies 2021).
STEP 4: after 20 weeks on the drug, people switched to placebo regained 6.9% of their weight over the next 48 weeks, while those who continued lost a further 7.9% (Rubino 2021).
After stopping: one year after STEP 1 ended, participants had regained about two-thirds of the weight they lost, and most heart and metabolic markers drifted back towards baseline (Wilding 2022).
Against tirzepatide: in a head-to-head trial in adults with obesity, weight loss at 72 weeks was 13.7% with semaglutide vs 20.2% with tirzepatide (Aronne 2025).
Type 2 diabetes, heart and kidneys
Blood sugar: in people early in type 2 diabetes, HbA1c fell by about 1.5% at 30 weeks vs almost no change on placebo (Sorli 2017).
SUSTAIN-6: in people with type 2 diabetes at high cardiovascular risk, heart attack, stroke or cardiovascular death occurred in 6.6% vs 8.9% on placebo over two years, but diabetic eye complications were more frequent (Marso 2016).
PIONEER 6: the oral tablet showed no excess cardiovascular risk compared with placebo (Husain 2019).
SELECT: in 17,604 adults with obesity and existing heart or vessel disease but no diabetes, major cardiovascular events fell from 8.0% to 6.5% over a mean of 3.3 years (Lincoff 2023).
FLOW: in people with type 2 diabetes and chronic kidney disease, serious kidney events and cardiovascular deaths were 24% less frequent (Perkovic 2024).
Liver
ESSENCE: in people with the inflammatory form of fatty liver disease (MASH) and moderate or advanced scarring, liver biopsies at 72 weeks improved more often on semaglutide than on placebo (Sanyal 2025). Longer-term outcomes are still being measured.
Verdict: the evidence for semaglutide is strong by the standards of this site. Several large, double-blind trials show lower body weight and blood sugar, and outcome trials show fewer cardiovascular and kidney events in specific high-risk groups. Two caveats apply throughout: nearly all trials were funded by the manufacturer, and the benefits depend on continuing the drug, since weight and metabolic markers return towards baseline after stopping.
In animals
Nothing yet
No summary in our library yet. We only publish one after checking it against the original papers.
In cells (in vitro)
Nothing yet
No summary in our library yet. We only publish one after checking it against the original papers.
How concentration changes with the amount of liquid added. A U-100 insulin syringe holds 1 mL in 100 units, so each unit is 0.01 mL. Step-by-step guide.
Step by step
Wash your hands and work on a clean, uncluttered surface. Let a refrigerated vial reach room temperature so the stopper is easier to pierce.
Wipe the rubber stopper of the peptide vial and of the bacteriostatic water with a fresh alcohol swab, and let them air-dry.
Draw the chosen volume of bacteriostatic water into a sterile syringe. With 2 mL, a 5 mg vial ends up at 2,500 mcg/mL, or 25 mcg per U-100 unit.
Insert the needle through the stopper and let the water run slowly down the inside wall of the vial, not straight onto the powder.
Swirl or roll the vial gently until the powder dissolves. Do not shake it: foaming can damage some peptides.
Check the solution against the light. It should be clear; cloudiness or particles mean something is wrong with the vial or the water.
Write the date and the volume of water on the label. Every unit calculation later depends on that volume.
Store the reconstituted Semaglutide vial in the refrigerator, away from light.
Concentration by volume
Concentration after adding the liquid, and how much peptide each U-100 unit (0.01 mL) holds.
Vial
Liquid added
Concentration
Per unit
5 mg
1 mL
5,000 mcg/mL
50 mcg
5 mg
2 mL
2,500 mcg/mL
25 mcg
5 mg
3 mL
1,667 mcg/mL
16.7 mcg
10 mg
1 mL
10,000 mcg/mL
100 mcg
10 mg
2 mL
5,000 mcg/mL
50 mcg
10 mg
3 mL
3,333 mcg/mL
33.3 mcg
Reconstitution calculator
Arithmetic only. It assumes the vial holds exactly what the label says.
Concentration
2,500 mcg/mL
Per U-100 unit
25 mcg
Volume for your amount
—
07
Measuring with a U-100 syringe
What each mark on an insulin syringe holds once the vial is mixed. This is arithmetic, not a dose.
Reading a U-100 syringe: how much peptide each mark holds in a 5 mg vial mixed with 2 mL. Not a dose.
Syringe mark
Volume
Peptide in that volume
5 units
0.05 mL
125 mcg
10 units
0.1 mL
250 mcg
20 units
0.2 mL
500 mcg
25 units
0.25 mL
625 mcg
50 units
0.5 mL
1.25 mg
100 units
1 mL
2.5 mg
A U-100 insulin syringe holds 1 mL in 100 units, so each unit is 0.01 mL. The marks measure volume, not peptide.
Syringes come in 0.3 mL (30 units), 0.5 mL (50 units) and 1 mL (100 units) sizes. The smaller ones have finer marks and are easier to read for small volumes.
Read the volume at the top edge of the plunger's rubber seal, at eye level.
Tap out air bubbles before reading: a bubble takes up volume and makes the reading wrong.
Use a new sterile syringe and needle every time, and dispose of them in a sharps container.
08
Supplies
What reconstituting and measuring a vial takes.
The peptide vial, with its certificate of analysis (COA) for that batch. See how to read a COA.
Bacteriostatic water (water with 0.9% benzyl alcohol), which keeps a multi-use vial from growing bacteria. Sterile water has no preservative.
Sterile syringes to add the water, and U-100 insulin syringes to measure.
Alcohol swabs for the stoppers.
A sharps container for used needles.
A label or marker to write the date and the volume of water on the vial.
09
Side effects, safety and legal status
The most common side effects in trials were gastrointestinal: nausea, diarrhoea, vomiting and constipation, mostly mild to moderate and most frequent while the dose is being increased. In STEP 2, 63.5% on the 2.4 mg dose reported gastrointestinal events vs 34.3% on placebo (Davies 2021), and in SELECT 16.6% stopped the drug because of side effects vs 8.2% on placebo (Lincoff 2023). Other known or suspected risks:
Gallbladder: trials of GLP-1 drugs as a class show more gallstones and gallbladder inflammation, especially at the higher doses used for weight loss (He 2022).
Pancreatitis and bowel problems: a US claims database study linked GLP-1 drugs used for weight loss with higher risks of pancreatitis, bowel obstruction and gastroparesis than another weight-loss drug, although these events were rare (Sodhi 2023).
Thyroid C-cell tumours: the US prescribing information carries a boxed warning because semaglutide caused thyroid C-cell tumours in rodents. Whether this happens in people is unclear: a French database study found more thyroid cancer after 1 to 3 years of GLP-1 drug use (Bezin 2023), while a larger Scandinavian cohort did not (Pasternak 2024).
Diabetic eye disease: in SUSTAIN-6, complications of diabetic retinopathy were more frequent on semaglutide than placebo (Marso 2016).
Optic nerve (NAION): in June 2025 the European Medicines Agency's safety committee concluded that non-arteritic anterior ischemic optic neuropathy, a cause of sudden vision loss, is a very rare side effect of semaglutide (up to 1 in 10,000 people).
Weight regain: stopping the drug is usually followed by regaining much of the lost weight (Wilding 2022).
Product quality: compounded and "research" semaglutide are not the approved products. Their identity, strength, purity and sterility have not been checked by the FDA, and some are sold as different salt forms that were never tested in the trials above.
FDA
FDA-approved as prescription drugs (Ozempic and Rybelsus for type 2 diabetes, Wegovy for chronic weight management).
Status checked on
Oct 26, 2026
10
Storing Semaglutide
Before mixing
Freeze-dried (lyophilised) peptide is the most stable form. It is usually kept refrigerated, or frozen for long storage, sealed and away from light.
Heat, moisture and light speed up degradation. Keep the vial in its box and avoid leaving it in a car or by a window.
After mixing
Keep the reconstituted vial refrigerated and away from light. Do not freeze it again: freezing and thawing a solution can break the peptide down.
How long a mixed vial stays good depends on the peptide and the diluent, and for most research peptides there is no published stability data. Follow the supplier's guidance and discard any vial that turns cloudy.
Pierce the stopper as few times as possible, and always with a new sterile needle after wiping it with alcohol.
Write the volume of water on the label (for example "2 mL"). Without it, the unit calculations cannot be checked later.
11
Questions about Semaglutide
Is Semaglutide FDA-approved?
FDA-approved as prescription drugs (Ozempic and Rybelsus for type 2 diabetes, Wegovy for chronic weight management).
What is the approved dose of Semaglutide?
The FDA label of each approved drug sets its dosing; section 02 shows it with the source. It applies to the prescription drug used as prescribed, not to research products.
What doses of Semaglutide have been studied?
Our library has 16 studies on Semaglutide. The doses each one used are in section 04, next to the study. They are not dosing instructions.
How much Semaglutide is in each syringe unit?
It depends on how much liquid is added to the vial. For a 5 mg vial with 2 mL, each U-100 unit holds 25 mcg. The reconstitution table and calculator work it out for other volumes.
What happens to weight after semaglutide is stopped?
In the STEP 1 extension, people regained about two-thirds of the weight they had lost within a year of stopping, and most improvements in blood pressure, blood sugar and blood fats faded. In STEP 4, people switched to placebo regained weight while those who continued kept losing.
Is research or compounded semaglutide the same as Ozempic or Wegovy?
No. Ozempic, Wegovy and Rybelsus are FDA-approved products made under regulated manufacturing. Compounded and so-called research versions have not been reviewed by the FDA, and their content, dose and sterility can differ. The trial results on this page apply to the approved products.
Does semaglutide cause thyroid cancer?
It caused thyroid C-cell tumours in rodents, which is why the US label carries a boxed warning. Human data are mixed: one French database study found a higher risk with GLP-1 drugs as a class, while a larger Scandinavian study did not. Long-term human data are still limited.
Is the tablet the same as the injection?
It is the same molecule, but the tablet (Rybelsus) is a once-daily form designed to be absorbed from the stomach. It has its own trials, including a cardiovascular safety trial, PIONEER 6, which found no excess risk compared with placebo.
How much bacteriostatic water goes into a 5 mg Semaglutide vial?
There is no single correct volume: it only changes the concentration. For a 5 mg vial, 1 mL gives 5,000 mcg/mL, 2 mL gives 2,500 mcg/mL, 3 mL gives 1,667 mcg/mL. More water makes small amounts easier to measure; less water keeps volumes small. Whatever volume is used, write it on the label.
What does one unit on an insulin syringe mean?
On a U-100 syringe, 100 units = 1 mL, so one unit is 0.01 mL. How much peptide that holds depends on the concentration of the vial, which depends on how much water was added.
Can doses from animal studies of Semaglutide be converted to people?
No. Animal doses are reported per kilogram for a different species, and scaling them to people is not reliable. That is why Upzo shows each study dose next to its study, unconverted.
How should Semaglutide be stored?
Unopened freeze-dried vials are usually kept refrigerated and away from light. Once mixed, keep the vial refrigerated and follow the supplier's guidance on how long it lasts.
12
References
Once-Weekly Semaglutide in Adults with Overweight or Obesity. Wilding JPH, Batterham RL, Calanna S, et al. New England Journal of Medicine. 2021;384:989-1002. doi:10.1056/NEJMoa2032183
Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. Frías JP, Davies MJ, Rosenstock J, et al. New England Journal of Medicine. 2021;385:503-515. doi:10.1056/NEJMoa2107519
Tirzepatide as Compared with Semaglutide for the Treatment of Obesity. Aronne LJ, Horn DB, le Roux CW, et al. New England Journal of Medicine. 2025;393:26-36. doi:10.1056/NEJMoa2416394
Efficacy and safety of once-weekly semaglutide monotherapy versus placebo in patients with type 2 diabetes (SUSTAIN 1): a double-blind, randomised, placebo-controlled, parallel-group, multinational, multicentre phase 3a trial. Sorli C, Harashima SI, Tsoukas GM, et al. The Lancet Diabetes & Endocrinology. 2017;5:251-260. doi:10.1016/S2213-8587(17)30013-X
Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes. Marso SP, Bain SC, Consoli A, et al. New England Journal of Medicine. 2016;375:1834-1844. doi:10.1056/NEJMoa1607141
Oral Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes. Husain M, Birkenfeld AL, Donsmark M, et al. New England Journal of Medicine. 2019;381:841-851. doi:10.1056/NEJMoa1901118
Semaglutide 2·4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2): a randomised, double-blind, double-dummy, placebo-controlled, phase 3 trial. Davies M, Færch L, Jeppesen OK, et al. The Lancet. 2021;397:971-984. doi:10.1016/S0140-6736(21)00213-0
Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance in Adults With Overweight or Obesity: The STEP 4 Randomized Clinical Trial. Rubino D, Abrahamsson N, Davies M, et al. JAMA. 2021;325:1414-1425. doi:10.1001/jama.2021.3224
Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Wilding JPH, Batterham RL, Davies M, et al. Diabetes, Obesity and Metabolism. 2022;24:1553-1564. doi:10.1111/dom.14725
Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. New England Journal of Medicine. 2023;389:2221-2232. doi:10.1056/NEJMoa2307563
Effects of Semaglutide on Chronic Kidney Disease in Patients with Type 2 Diabetes. Perkovic V, Tuttle KR, Rossing P, et al. New England Journal of Medicine. 2024;391:109-121. doi:10.1056/NEJMoa2403347
Phase 3 Trial of Semaglutide in Metabolic Dysfunction-Associated Steatohepatitis. Sanyal AJ, Newsome PN, Kliers I, et al. New England Journal of Medicine. 2025;392:2089-2099. doi:10.1056/NEJMoa2413258
Association of Glucagon-Like Peptide-1 Receptor Agonist Use With Risk of Gallbladder and Biliary Diseases: A Systematic Review and Meta-analysis of Randomized Clinical Trials. He L, Wang J, Ping F, et al. JAMA Internal Medicine. 2022;182:513-519. doi:10.1001/jamainternmed.2022.0338
Risk of Gastrointestinal Adverse Events Associated With Glucagon-Like Peptide-1 Receptor Agonists for Weight Loss. Sodhi M, Rezaeianzadeh R, Kezouh A, et al. JAMA. 2023;330:1795-1797. doi:10.1001/jama.2023.19574
GLP-1 Receptor Agonists and the Risk of Thyroid Cancer. Bezin J, Gouverneur A, Pénichon M, et al. Diabetes Care. 2023;46:384-390. doi:10.2337/dc22-1148
Glucagon-like peptide 1 receptor agonist use and risk of thyroid cancer: Scandinavian cohort study. Pasternak B, Wintzell V, Hviid A, et al. BMJ. 2024;385:e078225. doi:10.1136/bmj-2023-078225
Research and education only. Not medical advice. Many peptides on this site are not approved by the FDA for human use. Doses shown are the ones used in published studies and are not a recommendation. Talk to a licensed clinician before using any of them. Read the full disclaimer.