How much water do I add to a 30 mg Semaglutide vial?

There is no single correct amount: water changes how many units a dose is, not how many doses the vial holds. With 1 mL the vial is 30 mg/mL and 1.7 mg is 5.5 units (0.06 mL) on a U-100 insulin syringe. The units table gives 1, 2, 5 mL.

How many doses are in a 30 mg Semaglutide vial?

120 doses at 250 mcg, 60 doses at 500 mcg, 30 doses at 1 mg, 17 doses at 1.7 mg, 12 doses at 2.4 mg, 4 doses at 7.2 mg.

What does 1 unit equal in a 30 mg Semaglutide vial?

300 mcg with 1 mL, 150 mcg with 2 mL, 60 mcg with 5 mL of bacteriostatic water, on a U-100 syringe.

Label dosing, in units

Semaglutide 30 mg vial dosage

A 30 mg Semaglutide vial mixed with 1 mL of bacteriostatic water gives 30 mg/mL, so 1.7 mg is 5.5 units (0.06 mL) on a U-100 insulin syringe. At 1.7 mg a dose, one vial holds 17 doses.

Email me this plan, with a reminder before the vial's 28-day mark →

The FDA label doses: 0.25 mg once weekly for 4 weeks, then 0.5 mg for 4 weeks, then 1 mg for 4 weeks, then 1.7 mg for 4 weeks, then a maintenance dose of 1.7 mg or 2.4 mg once weekly. Patients tolerating 2.4 mg for at least 4 weeks who need additional weight reduction may increase to a maximum of 7.2 mg once weekly. The approved product is dosed as the label directs; vials sold outside that route are not the approved product. Evidence, side effects and legal status are on the full Semaglutide dosing page.

Semaglutide 30 mg vial at a glance

Vial: 30 mg of Semaglutide per vial
Label doses: 250 mcg, 500 mcg, 1 mg, 1.7 mg, 2.4 mg, 7.2 mg
How often: once weekly; dose increases no more often than every 4 weeks
Mixing example: 1 mL bacteriostatic water = 30 mg/mL; 1 unit = 300 mcg
Doses per vial: 120 at 250 mcg · 60 at 500 mcg · 30 at 1 mg · 17 at 1.7 mg · 12 at 2.4 mg · 4 at 7.2 mg
Route: Subcutaneous injection

What Semaglutide is

Class:: GLP-1 receptor agonist
Also called:: Ozempic, Wegovy, Rybelsus
Used for:: FDA-approved for type 2 diabetes in adults (Ozempic injection and tablets, Rybelsus), including cardiovascular risk reduction and, for the Ozempic injection, kidney-disease progression; and as Wegovy injection and tablets for chronic weight management and cardiovascular risk reduction in adults with obesity or overweight. The Wegovy injection is also approved for weight management from age 12 and for MASH with moderate to advanced liver fibrosis in adults.
Human evidence:: Strong human evidence. FDA has approved semaglutide products for several separate indications, each cleared on randomised trials reviewed by the agency: glycemic control in type 2 diabetes (Ozempic, approved 2017), cardiovascular and chronic-kidney-disease risk reduction in type 2 diabetes (Ozempic), chronic weight management (Wegovy, approved 2021), and cardiovascular risk reduction in adults with obesity or overweight and established cardiovascular disease (Wegovy). The adverse-reaction rates on the approved label come from that trial data. This rating describes the approved product, not the grey-market research-chemical vials sold under the same name.
Half-life:: Approximately 1 week - detectable in circulation for about 5 to 7 weeks after the last weekly 2.4 mg dose, per the approved label.
US status:: FDA-approved · prescription only. FDA-approved as Ozempic, Wegovy and Rybelsus, each with its own indication and label. Requires a prescriber. FDA has separately warned about compounded, counterfeit and "research use only" vials sold directly to consumers, which are not the approved product and are not made to the same quality standard.

The full picture, with every study: Semaglutide guide.

Units per dose: Semaglutide 30 mg vial

Water added	Concentration	1 unit =	250 mcg	500 mcg	1 mg	1.7 mg	2.4 mg	7.2 mg
1 mL	30 mg/mL	300 mcg	1 unit	1.5 units	3.5 units	5.5 units	8 units	24 units
2 mL	15 mg/mL	150 mcg	1.5 units	3.5 units	6.5 units	11.5 units	16 units	48 units
5 mL	6 mg/mL	60 mcg	4 units	8.5 units	16.5 units	28.5 units	40 units	over 100 units

U-100 insulin syringe (100 units = 1 mL), to the nearest half unit. Water volumes are examples. Other numbers: dosage calculator.

Each Semaglutide label dose in units

With 1 mL of water in a 30 mg vial (30 mg/mL). These are the doses the FDA label steps through; the order and timing are under label dosing below.

Dose	Draw on a U-100 syringe	Volume	Doses per vial
250 mcg	1 unit	0.01 mL	120
500 mcg	1.5 units	0.015 mL	60
1 mg	3.5 units	0.035 mL	30
1.7 mg	5.5 units	0.055 mL	17
2.4 mg	8 units	0.08 mL	12
7.2 mg	24 units	0.24 mL	4

How many doses a 30 mg vial holds

Dose	Doses per vial
250 mcg	120
500 mcg	60
1 mg	30
1.7 mg	17
2.4 mg	12
7.2 mg	4

Email me my Semaglutide 30 mg vial plan

Pick your water volume and dose and I will email you the numbers for this vial - units, volume, doses per vial and how long it lasts - plus the mixing and storage steps, and a reminder before the mixed vial reaches 28 days.

Semaglutide label dosing

0.25 mg once weekly for 4 weeks, then 0.5 mg for 4 weeks, then 1 mg for 4 weeks, then 1.7 mg for 4 weeks, then a maintenance dose of 1.7 mg or 2.4 mg once weekly. Patients tolerating 2.4 mg for at least 4 weeks who need additional weight reduction may increase to a maximum of 7.2 mg once weekly.

How often: once weekly; dose increases no more often than every 4 weeks.

From the FDA prescribing information [1]. A prescriber sets the dose and any increases.

How to mix a 30 mg Semaglutide vial

For this vial: 1 mL of bacteriostatic water makes 30 mg/mL, so 1.7 mg is 5.5 units (0.06 mL) on a U-100 insulin syringe. Pick a different volume from the units table if you want bigger or smaller draws; the number of doses stays the same.

Wipe the rubber stoppers of both the peptide vial and the bacteriostatic water vial with an alcohol swab and let the alcohol dry. ^[2][3]
With a new sterile needle and syringe, draw up the amount of bacteriostatic water you have chosen for the dilution. ^[2][3][4]
Inject the water into the peptide vial by aiming the stream against the inside glass wall, which helps prevent foaming. ^[5]
Swirl or roll the vial gently until the powder has fully dissolved; do not shake it. Do not inject the solution if it is cloudy or has particles in it. ^[2][3][5]
Label the vial with the date and time it was mixed, the amount of water added and how long it can be used after mixing. ^[2]
Store the mixed vial in the refrigerator at 2-8°C (36-46°F) and do not freeze it. ^[5]

Step by step with pictures: how to reconstitute peptides. About the water itself: bacteriostatic water.

Storing Semaglutide vials

Freeze-dried (lyophilized) peptide keeps far longer than peptide in solution; peptide suppliers advise storing the powder at -20°C away from bright light. ^[6]
Protect peptide vials from heat and light. ^[6][7]
Avoid repeated freeze-thaw cycles; a prescription peptide label also says not to freeze a vial once it has been mixed. ^[5][6]
Once a multi-dose vial, such as bacteriostatic water, has been opened (needle-punctured), date it and discard it within 28 days unless its manufacturer states another date. ^[8][9]

More detail: peptide storage and shelf life.

Injecting safely

Clean the injection site with an alcohol swab and let the skin dry completely before injecting. ^[10][11]
Pinch up a fold of skin and fat (not muscle) and insert the needle at a 45- to 90-degree angle: 90 degrees where there is enough fatty tissue, 45 degrees where there is little. ^[10][11][12]
Pulling back on the plunger (aspiration) is not necessary for a subcutaneous injection, because the chance of the needle being in a blood vessel is small. ^[10]
Inject slowly, at roughly 10 seconds per mL. ^[10]
Common sites are the belly, the thigh and the upper arm; rotate sites, keeping each injection at least 1 inch (2.5 cm) from the last. ^[5][10][11]

Hygiene and warning signs

Use a new sterile needle and syringe for every injection and every time you enter a vial; never reuse them. ^[4][8][11]
Never share needles, syringes or pens with anyone, even if the needle is changed; unsafe injection practices spread hepatitis B, hepatitis C and HIV. ^[4][7][8]
Put used needles and syringes in a sharps disposal container straight away (FDA-cleared if possible), never loose in the trash, recycling or toilet, and dispose of the container following your community's guidelines. ^[13][14]
Contact a health care provider if the injection site shows signs of infection, such as redness, swelling, red streaks or a fever. ^[11]

Where to inject: subcutaneous injection sites.

How Semaglutide works

Semaglutide is a GLP-1 analogue with 94% sequence homology to human GLP-1. Its peptide backbone is made by yeast fermentation, and it binds and activates the GLP-1 receptor, the same receptor the body's own GLP-1 uses. ^[1]
Two changes make it long-acting: a fatty di-acid attached at position 26 lets it bind albumin in the blood, and a change at position 8 protects it from breakdown by the enzyme DPP-4. Its elimination half-life is about one week, so it stays in circulation for roughly 5 to 7 weeks after the last injected dose. ^[1]
GLP-1 regulates appetite and calorie intake, and its receptor is found in several brain areas involved in appetite. Semaglutide lowers calorie intake, and the weight it removes is more fat mass than lean mass. ^[1]
It also stimulates insulin release and reduces glucagon release in a glucose-dependent way, and it slows gastric emptying. The label states that the exact mechanism behind its cardiovascular risk reduction has not been established. ^[1]

What the Semaglutide research found

Human evidence: strong human evidence. Each result says what was studied.

Human studyIn a 68-week randomised, placebo-controlled trial of 1,961 adults with obesity or overweight and no diabetes, body weight fell by 14.9% on semaglutide 2.4 mg weekly against 2.4% on placebo, alongside diet and activity counselling. ^[1]
Human studyIn a 68-week trial of 807 adults with type 2 diabetes and a BMI of 27 or more, weight fell by 9.6% on semaglutide 2.4 mg against 3.4% on placebo - a smaller effect than in people without diabetes. ^[1]
Human studyIn a cardiovascular outcomes trial of 17,604 adults aged 45 or over with established cardiovascular disease and overweight or obesity (no diabetes), followed for a median of 41.8 months, the combined rate of cardiovascular death, non-fatal heart attack or non-fatal stroke was 6.5% on semaglutide against 8.0% on placebo (hazard ratio 0.80). Cardiovascular death on its own did not reach statistical superiority. ^[1]
Human studyIn the STEP 4 withdrawal trial, 803 adults who had lost a mean 10.6% over a 20-week run-in were randomised to continue or switch to placebo. Over the next 48 weeks, those who continued lost a further 7.9% while those switched to placebo regained 6.9%. ^[15]
Human studyIn the STEP 1 extension, 327 adults were followed for a year after treatment stopped at 68 weeks. Those who had taken semaglutide (mean loss 17.3%) regained 11.6 percentage points of that loss, and most cardiometabolic improvements drifted back towards baseline; all extension analyses were exploratory. ^[16]

Semaglutide side effects and risks

FDA labelGastrointestinal effects are the most common. Across three trials of 2,116 adults on 2.4 mg for up to 68 weeks, rates against placebo were: nausea 44% vs 16%, diarrhoea 30% vs 16%, vomiting 24% vs 6%, constipation 24% vs 11% and abdominal pain 20% vs 10%. Adverse reactions led 6.8% to stop treatment, against 3.2% on placebo. ^[1]
FDA labelBoxed warning: in mice and rats, semaglutide caused dose- and duration-dependent thyroid C-cell tumours at clinically relevant exposures. Whether this happens in humans is unknown, and it is contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2. ^[1]
FDA labelAcute pancreatitis was confirmed in 4 semaglutide-treated patients (0.2 cases per 100 patient-years) against 1 on placebo in the weight-loss trials. Gallstones were reported in 1.6% vs 0.7% on placebo and cholecystitis in 0.6% vs 0.2%. ^[1]
FDA labelSevere gastrointestinal reactions occurred in 4.1% on the injection against 0.9% on placebo. Postmarketing reports describe acute kidney injury, sometimes needing dialysis, mostly in people dehydrated by nausea, vomiting or diarrhoea. ^[1]
FDA labelIn a 2-year trial in type 2 diabetes using the lower 0.5 mg and 1 mg weekly doses, diabetic retinopathy complications occurred in 3% on semaglutide against 1.8% on placebo, with a larger increase in people who already had retinopathy. Resting heart rate rose by a mean 1 to 4 beats per minute in the weight-loss trials. ^[1]
FDA labelSerious allergic reactions (anaphylaxis, angioedema) have been reported, and there are rare postmarketing reports of food being inhaled into the lungs during general anaesthesia or deep sedation because stomach emptying is slowed. ^[1]

Other things to know

Boxed warning: causes thyroid C-cell tumours in rodents; whether this occurs in humans is unknown. Contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2.
Gastrointestinal effects are the most common adverse reaction. In the trial data behind the Wegovy label, nausea occurred in 44% of patients versus 16% on placebo, with diarrhoea, vomiting and constipation all more common than placebo.
The label states that co-administration with any other GLP-1 receptor agonist, or with another semaglutide-containing product, is not recommended - relevant to anyone combining a prescription product with a grey-market one.
FDA has documented dosing errors, counterfeit product, unapproved salt-form substitution and fraudulent labelling specifically in the compounded and "research use only" semaglutide market.

Reported side effects and what the studies measured: Semaglutide side effects.

Where this vial size comes from

Semaglutide is sold as a 30 mg vial by the page below, each checked on the date shown. I list them as evidence that this size exists, not as a recommendation to buy from them.

99 Purity PeptidesvendorLists it as: "Semaglutide 5mg, 10mg, 20mg ,30mg 3ML | GLP-1 Research Peptide" - 30mg option · checked 2026-09-28

The doses come from the FDA label on the Semaglutide dosing page, and every number on this page is arithmetic on those doses and this vial size.

Other Semaglutide vial sizes

Questions

How much water do I add to a 30 mg Semaglutide vial?: There is no single correct amount: water changes how many units a dose is, not how many doses the vial holds. With 1 mL the vial is 30 mg/mL and 1.7 mg is 5.5 units (0.06 mL) on a U-100 insulin syringe. The units table gives 1, 2, 5 mL.
How many doses are in a 30 mg Semaglutide vial?: 120 doses at 250 mcg, 60 doses at 500 mcg, 30 doses at 1 mg, 17 doses at 1.7 mg, 12 doses at 2.4 mg, 4 doses at 7.2 mg.
What does 1 unit equal in a 30 mg Semaglutide vial?: 300 mcg with 1 mL, 150 mcg with 2 mL, 60 mcg with 5 mL of bacteriostatic water, on a U-100 syringe.

References (16 sources)

[1] DailyMed - Wegovy (semaglutide) injection, Novo Nordisk: FDA prescribing information (checked 2026-09-28)
[2] OpenStax, Rice University: 12.3 Preparing Unit-Dose Packaged Medications - Clinical Nursing Skills
[3] East Carolina University College of Nursing: Reconstitution of Medication
[4] Centers for Disease Control and Prevention: Considerations for Blood Glucose Monitoring and Insulin Administration
[5] DailyMed, National Library of Medicine: SEROSTIM (somatropin) for injection - prescribing information and instructions for use
[6] GenScript: Peptide Storage and Handling Guidelines
[7] DailyMed, National Library of Medicine: OZEMPIC (semaglutide) injection - prescribing information
[8] Centers for Disease Control and Prevention: Preventing Unsafe Injection Practices
[9] Pfizer: Bacteriostatic Water for Injection, USP - prescribing information
[10] OpenStax, Rice University: 12.5 Administering Subcutaneous Injections - Clinical Nursing Skills
[11] MedlinePlus, National Library of Medicine: Subcutaneous (SQ) injections
[12] Centers for Disease Control and Prevention: Chapter 6: Vaccine Administration - Pink Book
[13] US Food and Drug Administration: Best Way to Get Rid of Used Needles and Other Sharps
[14] US Food and Drug Administration: DOs and DON'Ts of Proper Sharps Disposal
[15] Rubino D, Abrahamsson N, Davies M et al. Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance in Adults With Overweight or Obesity: The STEP 4 Randomized Clinical Trial. JAMA. 2021;325(14):1414-1425.
[16] Wilding JPH, Batterham RL, Davies M et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes Obes Metab. 2022;24(8):1553-1564.