Dosage guide · 5 mg vial

Semaglutide Dosage Protocol

GLP-1 receptor agonist · Wegovy and Ozempic active ingredient

The Australian Wegovy label starts at 0.25 mg under the skin once weekly for weeks 1–4, then increases every 4 weeks to 0.5 mg, 1 mg, 1.7 mg and 2.4 mg. For this site's 5 mg reference vial, 2 mL gives 2.5 mg/mL, so the 0.25 mg start amount is 10 units (0.10 mL) on a U-100 syringe. Licensed Wegovy is a pre-filled pen and is not reconstituted.

How oftenOnce weekly

Starting dose0.25 mg

Start = units10 units

Mix2 mL BAC water

Reviewed 25 Oct 2026 · Education only, not medical advice

Semaglutide 5 mg reference vial

Not currently stocked by Peak Peptides Australia

No product photo — this strength isn't stocked by Peak

Dosage chart How to mix Supplies Calculator About Semaglutide References

01 · DOSAGE CHART

Semaglutide dosage chart

Official weekly step-up · 5 mg vial + 2 mL BAC water

BAC water added

Concentration2.5 mg/mL

1 unit (U-100)25 mcg= 0.01 mL

How oftenOnce weeklySubcutaneous injection

2 mL gives this 5 mg reference vial a concentration of 2.5 mg/mL, so 0.25 mg equals 10 units; it is not an instruction to mix a Wegovy or Ozempic pen.

Semaglutide dosage chart for a 5 mg reference vial mixed with 2 mL of bacteriostatic water
Week	Weekly dose	Syringe units
Weeks 1–4Start	0.25 mg	10 units0.1 mL
Weeks 5–8	0.5 mg	20 units0.2 mL
Weeks 9–12	1 mg	40 units0.4 mL
Weeks 13–16	1.7 mg	68 units0.68 mL
Week 17 onwardsMaintenance	2.4 mg	96 units0.96 mL

Once weekly · any time of day · subcutaneous injection

Increase no more often than every 4 weeks; the label allows delaying an increase when gastrointestinal symptoms are significant.

The Australian Wegovy label names 2.4 mg once weekly as the maintenance amount; it allows a temporary reduction to 1.7 mg when 2.4 mg is not tolerated.

The chart describes the licensed weekly amounts, while the units are only arithmetic for this site's nominal 5 mg reference vial.

This chart follows the Australian Wegovy label, but licensed Wegovy is a pre-filled pen rather than a reconstituted vial; Education only, not medical advice. Dose amounts follow Wegovy Australian Product Information (Therapeutic Goods Administration); units are recalculated for the vial and mix selected above.

02 · HOW TO MIX

Mixing a 5 mg reference vial with 2 mL of BAC water

Using a 1 mL (100-unit) insulin syringe, 2 full draws of bacteriostatic water gives 2.5 mg/mL.

1
Add the water slowly
Wipe both rubber stoppers with an alcohol swab and let them dry. Draw 2 mL of bacteriostatic water and let it run slowly down the inside of the vial wall — not straight onto the powder.
2
Swirl gently
Swirl or roll the vial gently until the powder has dissolved. Give it a few minutes to settle if needed.
3
Don't shake it
Shaking can damage the peptide and cause foaming. Gentle swirling only.
4
Check it's fully clear
Only use it once it is fully clear with no particles. Label the vial with the date and 2.5 mg/mL, then store it in the fridge at 2–8 °C.

Full illustrated reconstitution guide

03 · SUPPLIES NEEDED

What you'll need

Counts follow the dosage chart above at the highest amount in each step, using a 5 mg reference vial mixed with 2 mL.

Length of protocol

1Semaglutide 5 mg reference vial3 mg needed in total

91 mL insulin syringesU-100, 27–31G · one per draw + one per vial mixed

1BAC water 10 mL bottle2 mL used for mixing

18Alcohol swabsSkin + stopper, every time

Plus an approved sharps container. Syringes and swabs are sold by Australian pharmacies — Peak Peptides and Pure Performance supply the bacteriostatic water.

Peak Peptides Australia Bacteriostatic water 10 mL

Bacteriostatic water 10 mLPeak Peptides Australia

Pure Performance Australia Bacteriostatic water 10 mL

Bacteriostatic water 10 mLPure Performance Australia

04 · CALCULATOR

Check a different amount

Enter your vial, water and dose to see the matching syringe units.

Concentration Calculator

Labelled Vial Amount (mg)

Verified Final Liquid Volume2 mL

Amount to Evaluate (not a recommendation)

Concentration

2.50 mg/mL

(2500 mcg/mL)

Calculated Liquid Volume

0.100 mL

Equivalent U-100 volume scale position

10markings (not biological IU)

Illustration of a U-100 volume scale, not preparation or injection guidance

05 · PROTOCOL DETAILS

About Semaglutide

Protocol overview

Starting amount: 0.25 mg once weekly for weeks 1–4
How it increases: 0.5 mg, 1 mg and 1.7 mg in consecutive 4-week steps
Maintenance: 2.4 mg once weekly from week 17 under the Australian Wegovy label
Frequency: Once weekly
When to take it: Any time of day, with or without meals, on the same weekly schedule
Reference calculation: 5 mg plus 2 mL = 2.5 mg/mL; 0.25 mg = 10 U-100 units

Storage

Licensed pen before use: Refrigerate Wegovy at 2–8 °C in its original carton and protect it from light.
Licensed pen at room temperature: The Australian Wegovy PI permits up to 28 days below 30 °C before use.
Reference mixed vial: No TGA-labelled 5 mg reconstitution or mixed-vial storage period exists; follow only the exact product's instructions.
Never: Do not freeze Wegovy, use it if frozen, or use it if it is not clear and colourless.

How it works

Semaglutide is a glucagon-like peptide-1, or GLP-1, analogue. It activates GLP-1 receptors involved in glucose regulation in the pancreas and appetite regulation in the brain.

The TGA product information says albumin binding and resistance to DPP-4 breakdown give semaglutide a half-life of about 1 week. In clinical studies it reduced energy intake and increased fullness and satiety, while its glucose effects include glucose-dependent stimulation of insulin and lowering of glucagon.

Illustrated mechanism explainer

What the research shows

Wegovy was registered by the TGA on 26 February 2024. The TGA lists Wegovy for chronic weight management and Ozempic for management of type 2 diabetes in adults.
In STEP 1, 1,961 adults without diabetes received 2.4 mg weekly semaglutide or placebo with lifestyle intervention for 68 weeks. Mean body-weight change was −14.9% with semaglutide and −2.4% with placebo.
In STEP 1, 86.4% of semaglutide participants and 31.5% of placebo participants achieved at least 5% body-weight reduction at week 68; gastrointestinal events led to treatment discontinuation in 4.5% and 0.8%, respectively.
The Australian Wegovy PI reports that, after 20 weeks of dosing, energy intake during an unrestricted meal was 35% lower with Wegovy than with placebo.

Reported side effects

In 68-week controlled data in the Australian PI, nausea occurred in 43.9% with Wegovy and 16.1% with placebo; diarrhoea occurred in 29.7% and 15.9%; vomiting occurred in 24.5% and 6.3%.
Constipation occurred in 24.2% with Wegovy and 11.1% with placebo in the same data. These gastrointestinal effects were most frequent during dose escalation.
The TGA PI reports adjudication-confirmed acute pancreatitis in 0.2% with Wegovy and less than 0.1% with placebo; it advises stopping treatment if pancreatitis is suspected.
Cholelithiasis was reported in 1.6% and cholecystitis in 0.6% with Wegovy, versus 1.1% and 0.3% with placebo in the Australian PI.
Hypoglycaemia risk is higher when semaglutide is used with insulin or a sulfonylurea. The TGA also warns of dehydration and acute kidney injury with persistent nausea, vomiting or diarrhoea.

Important notes

Wegovy and Ozempic are TGA-registered prescription medicines. Their labelled dosage forms are solutions in pre-filled pens, not a 5 mg lyophilised vial, so use the prescribed product and its current Product Information.
The Australian Wegovy PI says substances added to Wegovy may degrade semaglutide and Wegovy must not be mixed with other medicinal products. Do not add bacteriostatic water to, or transfer solution from, a Wegovy or Ozempic pen.
The label carries important risks including pancreatitis and gallbladder disease. It also reports thyroid C-cell tumours in rodents; the relevance to humans is considered low but cannot be excluded.
Semaglutide should not be used during pregnancy; the Australian PI says it should be stopped at least 2 months before a planned pregnancy.
WADA's 2026 Monitoring Program places markers of semaglutide on its in- and out-of-competition monitoring program. WADA describes this program as covering substances not on its Prohibited List.
Never use a mixed vial that is cloudy or has particles in it.

Injection basics

Use a new sterile 1 mL (100-unit) U-100 insulin syringe, 27–31G, every time — never reuse or share.
Wipe the vial stopper and the skin with an alcohol swab and let both dry first.
Inject under the skin (subcutaneously) of the abdomen, thigh or upper arm, and rotate sites.
Put used syringes straight into an approved sharps container — the NDSS lists Australian disposal options.

Guidance: World Health Organization · National Diabetes Services Scheme (NDSS)

06 · QUICK ANSWERS

Semaglutide questions

How many units is the 0.25 mg Semaglutide starting amount?

For this reference calculation, 5 mg plus 2 mL gives 2.5 mg/mL. The 0.25 mg starting amount is 10 U-100 units, or 0.10 mL. This conversion does not apply to a Wegovy or Ozempic pen.

How many units are the weekly Semaglutide steps in a 5 mg vial?

At 2.5 mg/mL from a 5 mg vial plus 2 mL, 0.5 mg is 20 units (0.20 mL), 1 mg is 40 units (0.40 mL), 1.7 mg is 68 units (0.68 mL), and 2.4 mg is 96 units (0.96 mL).

How much water is used for the 5 mg Semaglutide reference calculation?

The default calculator mix is 2 mL in a nominal 5 mg vial, which is 2.5 mg/mL or 25 mcg per U-100 unit. This is arithmetic for the site's reference vial, not a licensed Wegovy or Ozempic preparation method.

How long does a 5 mg Semaglutide reference vial last?

By mass arithmetic, 5 mg contains 20 amounts of 0.25 mg, 10 amounts of 0.5 mg, 5 amounts of 1 mg, 2 complete amounts of 1.7 mg, or 2 complete amounts of 2.4 mg. At the displayed full schedule, 8 weeks total 3 mg, 16 weeks total 13.8 mg and 24 weeks total 33 mg; actual use must follow the exact product's discard instructions.

07 · SOURCES