Semaglutide Dosage Calculator:
Reconstitution, Units
& Weight Loss Planner
The most complete free semaglutide dosage calculator on the web — purpose-built for people using compounded semaglutide, Ozempic, or Wegovy. Whether you need to calculate exact syringe units from your vial concentration, work out how much bacteriostatic water to mix, or project your weight loss based on STEP trial data, the Heart Score Calculator has every tool in one place. No sign-up, no ads, no paywalls.
Most peptide calculators only do one job — mg to units, or just reconstitution. Our all-in-one semaglutide dosage calculator covers 5 complete modes: peptide reconstitution with BAC water, mg to syringe units conversion, STEP trial weight loss projection by dose, protein intake for muscle preservation, and half-life tracking. It also covers the new FDA-approved 7.2mg high-dose (HD) semaglutide — which most competitors have not updated for. All free.
This calculator is for educational purposes only. Semaglutide (Ozempic®, Wegovy®, Rybelsus®) is a prescription-only medication. Compounded semaglutide availability is subject to FDA regulations and pharmacy status. Never adjust your prescribed dose without consulting your licensed healthcare provider. Incorrect dosing can cause serious harm.
Semaglutide Calculator
STEP Trial DataEnter vial size, BAC water volume, and dose. Get exact syringe units, concentration, and draw volume instantly.
Total mg in your vial
mL of bacteriostatic water
Typical: 0.25, 0.5, 1.0, 1.7, 2.4mg
Know your concentration? Enter dose and concentration to get exact U-100 syringe units instantly.
Common: 1, 2, 2.5, 5 mg/mL
Weight loss projection based on STEP 1, 2, 3 and STEP UP trial data. Population estimates — individual results vary.
GLP-1 medication users need higher protein to preserve lean muscle during rapid weight loss. Uses semaglutide-specific targets.
Semaglutide has a half-life of approximately 7 days (168 hours). Steady state is reached after 4–5 weeks of consistent weekly dosing.
Always verify your vial's actual concentration against the label before injecting. Concentrations vary between compounding pharmacies and batch formulations. Confirm all doses with your prescribing provider.
Semaglutide Dosing Chart — Complete Titration Schedule (Ozempic, Wegovy & Compounded)
Every form of injectable semaglutide — whether you are using brand-name Wegovy for weight loss, Ozempic for type 2 diabetes, or a compounded semaglutide from a licensed 503A/503B pharmacy — follows the same gradual dose escalation protocol. The titration schedule is designed to allow your gastrointestinal system to adapt before reaching therapeutic doses, which dramatically reduces nausea, vomiting, and other common early side effects.
You can use the Heart Score Calculator semaglutide tool above to convert any dose on this chart into exact insulin syringe units for your specific vial concentration. If you are also managing cardiovascular risk, our ABG Calculator and Heart Risk Score Calculator can help you track the broader cardiometabolic picture — semaglutide carries FDA approval for reducing major cardiovascular events in people with established heart disease (SELECT trial).
| Weeks | Dose | Injection Freq. | Phase | Expected Weight Loss (68 wk) |
|---|---|---|---|---|
| 1–4 | 0.25 mg | Once weekly | Initiation | Sub-therapeutic (GI adaptation) |
| 5–8 | 0.5 mg | Once weekly | Escalation | ~5–8% body weight |
| 9–12 | 1.0 mg | Once weekly | Escalation | ~8–11% |
| 13–16 | 1.7 mg | Once weekly | Escalation | ~11–13% (Wegovy-specific step) |
| 17+ | 2.4 mg | Once weekly | Maintenance | ~15–17% (STEP 1 trial average) |
| HD | 7.2 mg NEW 2026 | Once weekly | High Dose | ~20.7% (STEP UP trial) |
New in 2026: The 7.2mg High-Dose Semaglutide. The FDA approved a 7.2mg weekly injection dose of Wegovy in March 2026 following the STEP UP Phase 3b trial published in The Lancet Diabetes & Endocrinology. Participants on 7.2mg achieved an average body weight reduction of 20.7% over 68 weeks — approaching the results previously only seen with tirzepatide. Our semaglutide peptide dosage calculator is one of the first online tools to support the 7.2mg dose in the weight loss projection model. See our Tirzepatide Calculator for a side-by-side comparison of weight loss outcomes between both drugs.
How to Calculate Semaglutide Dosage — The Peptide Reconstitution Formula
When using compounded semaglutide from a lyophilised (freeze-dried) vial, converting your prescribed dose in milligrams to the correct number of units on an insulin syringe requires two straightforward calculations. This is the core function of a semaglutide peptide dosage calculator, and the Heart Score Calculator automates all of it — but understanding the underlying maths helps you catch errors and calculate confidently.
Step 1: Calculate Concentration (the Semaglutide Dilution Formula)
Before you can draw your dose, you need to know how concentrated your solution is after adding bacteriostatic water. This is your semaglutide mixing ratio — and it changes every time you choose a different BAC water volume. The peptide reconstitution ratio calculator formula is:
Step 2: Convert mg to Insulin Syringe Units
Once you know your concentration, the mg to units peptide conversion for a standard U-100 insulin syringe is simple. A U-100 syringe holds exactly 1mL in 100 units — so multiplying your draw volume (in mL) by 100 gives your unit count. This is the core of any injectable peptide calculator:
Choosing Your BAC Water Volume — The Semaglutide Mixing Ratio Calculator
The bacteriostatic water mixing peptide approach you choose affects both your concentration and how many units you draw for each dose. Rather than picking an arbitrary amount, work backwards from a target draw volume that falls comfortably on your syringe. Common practical choices for semaglutide are:
| Vial Size | BAC Water | Concentration | 0.25mg = | 0.5mg = | 1.0mg = | 2.4mg = |
|---|---|---|---|---|---|---|
| 3 mg | 1.5 mL | 2.0 mg/mL | 12 units | 25 units | 50 units | — |
| 5 mg | 2 mL | 2.5 mg/mL | 10 units | 20 units | 40 units | 96 units |
| 5 mg | 1 mL | 5.0 mg/mL | 5 units | 10 units | 20 units | 48 units |
| 10 mg | 2 mL | 5.0 mg/mL | 5 units | 10 units | 20 units | 48 units |
| 10 mg | 4 mL | 2.5 mg/mL | 10 units | 20 units | 40 units | 96 units |
| 15 mg | 3 mL | 5.0 mg/mL | 5 units | 10 units | 20 units | 48 units |
| 20 mg | 4 mL | 5.0 mg/mL | 5 units | 10 units | 20 units | 48 units |
Table values for U-100 insulin syringes (1mL = 100 units). Always verify against your specific vial label and provider instructions.
If you prefer a different concentration to get a draw volume you can see more clearly on your syringe, use our semaglutide reconstitution calculator above. The Heart Score Calculator reconstitution tool instantly computes any combination of vial size, BAC water volume, and target dose — including how many doses your vial will provide and the mcg per syringe unit for microdosing reference.
How to Reconstitute Semaglutide Peptide — Step-by-Step Guide
Reconstituting semaglutide means dissolving the lyophilised (freeze-dried) peptide powder with bacteriostatic water to create a stable, injectable solution. Compounded semaglutide always requires this step — brand-name Ozempic and Wegovy pens come pre-filled and do not. Getting the technique right protects both the peptide structure and your safety.
You need: semaglutide vial (lyophilised powder), bacteriostatic water (BAC water — not sterile water, not tap water), U-100 insulin syringes, alcohol swabs (70% isopropyl), clean workspace. BAC water contains 0.9% benzyl alcohol which prevents bacterial contamination across multiple draws. Sterile water has no preservative and is single-use only — using it for a multi-dose vial creates infection risk.
Before opening anything, use our semaglutide vial dosage calculation tool above to confirm exactly how much BAC water to add. Enter your vial size and target dose — the peptide reconstitution ratio calculator will show your optimal BAC water volume, resulting concentration, and exact syringe units. Write this down before proceeding.
Wash your hands thoroughly with soap for at least 20 seconds. Wipe the rubber stopper of both the semaglutide vial and the BAC water vial with a fresh alcohol swab. Wait a full 15 seconds for the alcohol to dry completely before piercing — injecting through wet alcohol can introduce it into your solution.
Draw your calculated BAC water volume into a syringe. Insert the needle into the semaglutide vial and angle it so the tip touches the inside glass wall — not the powder cake at the bottom. Inject the BAC water slowly along the glass wall so it trickles down onto the powder. Never force the liquid directly onto the lyophilised powder; the mechanical impact disrupts the peptide structure and can cause aggregation.
After injecting the BAC water, gently swirl the vial in slow, circular motions. The powder should fully dissolve within 1–5 minutes, producing a completely clear, colourless solution. Vigorous shaking generates mechanical force that breaks the peptide bonds in semaglutide, reducing potency. If the solution remains cloudy after 10 minutes of gentle swirling, or you see particles or discolouration, do not use the vial.
Write the date of reconstitution and the concentration (e.g. "2.5 mg/mL — mixed 20 May 2026") directly on the vial. Refrigerate immediately at 36–46°F (2–8°C). Reconstituted semaglutide is stable for 28–56 days when stored correctly. Never freeze reconstituted semaglutide — freeze-thaw damage permanently alters the molecule. Discard if the solution becomes cloudy, develops particles, or changes colour.
What Is Semaglutide and How Does It Work for Weight Loss?
Semaglutide is a GLP-1 (glucagon-like peptide-1) receptor agonist developed by Novo Nordisk. It is the active ingredient in three FDA-approved medications: Ozempic® (once-weekly subcutaneous injection for type 2 diabetes), Wegovy® (once-weekly subcutaneous injection for chronic weight management), and Rybelsus® (daily oral tablet for type 2 diabetes). All injectable forms use the same weekly subcutaneous dosing schedule — the key clinical difference is the approved maximum dose and the patient population each targets.
Semaglutide works by mimicking the GLP-1 hormone that the gut naturally releases after eating. When you inject semaglutide, it activates GLP-1 receptors in the brain's appetite centres (particularly the hypothalamus), slows gastric emptying, stimulates insulin secretion in a glucose-dependent manner, and suppresses glucagon release. The combined effect is significantly reduced appetite, slower digestion, improved blood glucose control, and — over weeks to months — meaningful, sustained weight loss. Unlike older appetite suppressants, semaglutide does not cause dependence or act on dopamine pathways.
The landmark STEP 1 clinical trial — a randomised, double-blind, placebo-controlled study — showed that adults with obesity taking 2.4mg semaglutide weekly for 68 weeks lost an average of 14.9% of their body weight compared to 2.4% with placebo. The SELECT cardiovascular outcomes trial further demonstrated that semaglutide 2.4mg reduces major adverse cardiovascular events by 20% in people with established cardiovascular disease — an effect captured in our Heart Risk Score Calculator.
Semaglutide's molecular structure is 94% identical to natural human GLP-1, with a fatty acid chain attached to extend its half-life from 2 minutes (native GLP-1) to approximately 7 days. This extended half-life is what makes once-weekly dosing possible and creates the sustained appetite suppression that distinguishes semaglutide from older weight-loss drugs.
The SURMOUNT-5 head-to-head trial showed tirzepatide produced 20.2% weight loss vs 13.7% with semaglutide 2.4mg. However, the new 7.2mg semaglutide HD dose (STEP UP trial, 2025) achieves ~20.7% weight loss — narrowing the gap significantly. Our Tirzepatide Calculator lets you compare projected outcomes for both drugs side by side.
Compounded semaglutide contains the same active molecule but is produced by licensed 503A/503B pharmacies under different quality oversight than FDA-approved Ozempic and Wegovy. Compounded versions typically cost 70–85% less. Since the FDA declared the semaglutide shortage over in late 2024, compounding regulations have tightened — always request a Certificate of Analysis from your pharmacy.
Studies show that 25–40% of weight lost on semaglutide can be lean muscle, not fat — particularly without adequate protein intake and resistance training. GLP-1 users need 1.2–1.6g of protein per kg of body weight daily to protect lean mass. Use our protein calculator mode above to find your exact daily target and reduce the risk of metabolic slowdown during your weight loss journey.
Ozempic vs Wegovy vs Compounded Semaglutide — Key Differences
All three products contain the same active molecule — semaglutide — but differ in indication, maximum approved dose, and the need for reconstitution. If you are using a semaglutide dosage calculator for weight loss, the key details to confirm before calculating are: which product you are using, your exact vial concentration (for compounded), and your current position on the titration schedule.
| Feature | Ozempic® (Novo Nordisk) | Wegovy® (Novo Nordisk) | Compounded Semaglutide |
|---|---|---|---|
| Primary Indication | Type 2 Diabetes | Chronic Weight Management | Varies by prescription |
| FDA Approval | ✓ Approved (2017) | ✓ Approved (2021) | Not FDA approved |
| Max Weekly Dose | 2.0 mg | 2.4 mg (+ 7.2 mg HD) | Varies by compounder |
| Reconstitution Needed | No (auto-pen) | No (auto-pen) | Yes — use our calculator |
| 1.7 mg Titration Step | No | Yes (Wegovy-specific) | Provider discretion |
| Typical Monthly Cost | ~$900–$1,200 | ~$1,300–$1,600 | $150–$400 |
| Active Molecule | Semaglutide | Semaglutide | Semaglutide |
| Cardiovascular Benefit (SELECT) | ✓ Proven (20% MACE reduction) | ✓ Same molecule | Same molecule |
| 2025/2026 Regulatory Status | Fully available | Fully available | 503A/503B oversight |