Semaglutide Dose Chart: Complete Conversion Guide for Every Concentration

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> Reviewed by FormBlends Medical Team · Last updated April 2026 · 14 sources cited

Key Takeaways

• The same semaglutide dose (e.g., 0.5 mg) requires different unit counts on a U-100 syringe depending on vial concentration: 50 units at 1 mg/mL, 20 units at 2.5 mg/mL, or 10 units at 5 mg/mL
• Compounded semaglutide comes in six common concentrations (1, 2, 2.5, 5, 10, and 12.5 mg/mL), each requiring its own conversion math
• The FDA-approved titration schedule (0.25 mg → 0.5 mg → 1 mg → 1.7 mg → 2.4 mg) remains the same regardless of concentration, but the volume you draw changes
• Dosing errors occur in 6.8% of compounded semaglutide patients within the first 90 days, most commonly when switching pharmacies without re-checking concentration (Johnson et al., Journal of Managed Care Pharmacy 2025)

Direct answer (40-60 words)

A semaglutide dose chart converts milligram doses to syringe units based on your vial's concentration. At 5 mg/mL (most common for compounded semaglutide), 0.5 mg equals 10 units on a U-100 insulin syringe. At 2.5 mg/mL it's 20 units. At 10 mg/mL it's 5 units. The concentration on your vial label determines the conversion.

Table of contents

1. Why concentration matters more than dose
2. Master conversion chart for all six common semaglutide concentrations
3. How to identify your vial's concentration in 10 seconds
4. The FDA-approved titration schedule and what it means in units
5. What most dosing charts get wrong about compounded semaglutide
6. Step-by-step: drawing your dose with a U-100 insulin syringe
7. The Three Failure Modes of semaglutide dose conversion
8. When higher concentration is better (and when it's not)
9. Reconstitution math: calculating concentration from powder
10. Storage requirements and shelf life by concentration
11. When to call your provider about dosing questions
12. FAQ

Why concentration matters more than dose

Your prescribed dose (the milligrams) stays constant across the titration schedule. What changes between pharmacies and vial batches is the concentration: how many milligrams of semaglutide are dissolved in each milliliter of solution.

This creates a math problem most patients don't expect. A 0.5 mg dose is always 0.5 mg of active drug entering your body. But the volume you draw, and therefore the unit count on your syringe, depends entirely on how concentrated the solution is.

At 5 mg/mL, there are 5 milligrams of semaglutide in every milliliter. To get 0.5 mg you need one-tenth of a milliliter (0.1 mL), which equals 10 units on a U-100 insulin syringe.

At 2.5 mg/mL, there are only 2.5 milligrams per milliliter. To get the same 0.5 mg you need 0.2 mL, which equals 20 units.

Same dose. Different concentration. Different unit count.

The convention of using "units" to describe semaglutide doses is borrowed from insulin, where U-100 syringes are calibrated so that 1 unit equals 0.01 mL. Semaglutide has no unit-based potency (it's not insulin), but we use insulin syringes because they're the only widely available syringes with markings small enough to measure the tiny volumes semaglutide requires.

Master conversion chart for all six common semaglutide concentrations

The table below covers every dose in the FDA-approved titration schedule across the six concentrations you're most likely to encounter from U.S. compounding pharmacies.

Concentration	0.25 mg	0.5 mg	1 mg	1.7 mg	2.4 mg
1 mg/mL	25 units (0.25 mL)	50 units (0.50 mL)	100 units (1.00 mL)	170 units (1.70 mL)	240 units (2.40 mL)
2 mg/mL	12.5 units (0.125 mL)	25 units (0.25 mL)	50 units (0.50 mL)	85 units (0.85 mL)	120 units (1.20 mL)
2.5 mg/mL	10 units (0.10 mL)	20 units (0.20 mL)	40 units (0.40 mL)	68 units (0.68 mL)	96 units (0.96 mL)
5 mg/mL	5 units (0.05 mL)	10 units (0.10 mL)	20 units (0.20 mL)	34 units (0.34 mL)	48 units (0.48 mL)
10 mg/mL	2.5 units (0.025 mL)	5 units (0.05 mL)	10 units (0.10 mL)	17 units (0.17 mL)	24 units (0.24 mL)
12.5 mg/mL	2 units (0.02 mL)	4 units (0.04 mL)	8 units (0.08 mL)	13.6 units (0.136 mL)	19.2 units (0.192 mL)

Highlighted patterns:

• 5 mg/mL is the most common concentration for compounded semaglutide because it balances readable unit counts with reasonable injection volumes. Every 1 mg of dose equals 20 units, making mental math straightforward.
• 2.5 mg/mL is used when pharmacies want to fit a month's supply in a smaller vial or when patients are at very low starting doses (0.25 mg) and need a more readable unit count.
• 10 mg/mL and 12.5 mg/mL are the highest concentrations most pharmacies compound. These are used for patients at maintenance doses (1.7 mg or 2.4 mg) to minimize injection volume. Doses below 5 units become hard to draw accurately on a standard U-100 syringe.
• 1 mg/mL is rare for semaglutide but occasionally used for patients with extreme needle anxiety who prefer the smallest possible needle and are willing to inject larger volumes.

A rule of thumb for the most common concentration (5 mg/mL): divide your milligram dose by 5, then multiply by 100 to get units. So 1 mg ÷ 5 = 0.2 mL × 100 = 20 units.

How to identify your vial's concentration in 10 seconds

The concentration is printed on the vial label in one of three formats:

Format 1: Direct concentration "Semaglutide Injection 5 mg/mL" means 5 milligrams per milliliter.

Format 2: Total amount over total volume "Semaglutide 25 mg / 5 mL Multi-Dose Vial" means divide 25 by 5 to get 5 mg/mL.

Format 3: Powder for reconstitution "Semaglutide for Reconstitution, 10 mg" means the concentration is determined when you add bacteriostatic water. The pharmacy's reconstitution instructions (usually on a separate insert) tell you how much water to add. If it says "add 2 mL," the final concentration is 10 mg ÷ 2 mL = 5 mg/mL.

If your vial only lists total milligrams without a volume (e.g., "Semaglutide 25 mg"), the concentration is in the pharmacy's dispensing paperwork, the patient portal, or the prescription label on the box. Don't guess. Two pharmacies dispensing "25 mg vials" can use different volumes.

What to do if you can't find the concentration: Call the pharmacy before drawing a dose. Most compounding pharmacies have a 24-hour pharmacist line. Drawing the wrong volume because you assumed the concentration is the single most common preventable dosing error.

The FDA-approved titration schedule and what it means in units

The FDA-approved semaglutide titration schedule for chronic weight management (Wegovy dosing) is:

• Weeks 1-4: 0.25 mg once weekly
• Weeks 5-8: 0.5 mg once weekly
• Weeks 9-12: 1 mg once weekly
• Weeks 13-16: 1.7 mg once weekly
• Week 17 onward: 2.4 mg once weekly (maintenance)

The schedule is the same whether you're using brand-name Wegovy pens or compounded semaglutide from a vial. The difference is that pen users don't think about units or milliliters (the pen clicks to the dose), while vial users need to convert milligrams to syringe units using their vial's concentration.

Here's what the titration looks like at 5 mg/mL (most common):

• Weeks 1-4: 5 units (0.05 mL)
• Weeks 5-8: 10 units (0.10 mL)
• Weeks 9-12: 20 units (0.20 mL)
• Weeks 13-16: 34 units (0.34 mL)
• Week 17 onward: 48 units (0.48 mL)

At 2.5 mg/mL, the same schedule becomes:

• Weeks 1-4: 10 units
• Weeks 5-8: 20 units
• Weeks 9-12: 40 units
• Weeks 13-16: 68 units
• Week 17 onward: 96 units

The dose escalation pattern is identical. Only the volume changes.

Clinical note: some providers use a slower titration (staying at each step for 6 to 8 weeks instead of 4) to reduce gastrointestinal side effects. The STEP 1 trial (Wilding et al., New England Journal of Medicine 2021) used the 4-week escalation, but real-world practice often extends it. Your provider's titration instructions supersede the FDA schedule.

What most dosing charts get wrong about compounded semaglutide

Most published semaglutide dose charts make one of three errors:

Error 1: Assuming a single concentration. Generic charts show "0.5 mg = 10 units" without specifying that this is only true at 5 mg/mL. Patients using 2.5 mg/mL vials see "10 units" and draw half the intended dose.

Error 2: Confusing Ozempic dosing with Wegovy dosing. Ozempic (semaglutide for type 2 diabetes) uses a different titration schedule: 0.25 mg for 4 weeks, then 0.5 mg, with optional escalation to 1 mg or 2 mg. Wegovy (semaglutide for weight management) goes to 2.4 mg. Charts that mix the two create confusion about the target maintenance dose.

Error 3: Listing unit counts that don't align with syringe markings. A chart that says "1.7 mg = 34 units at 5 mg/mL" is correct, but a 0.3 mL U-100 syringe only has markings at whole and half units. Drawing 34 units is straightforward. Drawing 34.2 units (if someone tried to be more precise) is not. The best charts round to the nearest readable marking.

The correction: a world-class dose chart specifies concentration in every cell, distinguishes Ozempic from Wegovy schedules, and rounds unit counts to the nearest half-unit for doses below 50 units.

Step-by-step: drawing your dose with a U-100 insulin syringe

This protocol assumes a pre-mixed vial of compounded semaglutide at 5 mg/mL and a 0.5 mL U-100 insulin syringe with a 31-gauge, 5/16-inch needle. Adjust unit count using the chart above for other concentrations.

Materials needed:

• Compounded semaglutide vial
• U-100 insulin syringe (0.3 mL or 0.5 mL barrel)
• Two alcohol prep pads
• Sharps container
• Your dose chart (printed or on your phone)

Steps:

1. Wash hands with soap and water for at least 20 seconds. Dry completely.

1. Inspect the vial. Semaglutide should be clear and colorless. Slight straw-yellow tint is normal if the pharmacy added B12. Cloudiness, particles, or unusual color means don't use it. Contact the pharmacy.

1. Confirm your dose in units. Check your dose chart. If you're on 0.5 mg and your vial is 5 mg/mL, you're drawing 10 units. Write the unit count on the vial box in permanent marker the first time so you don't need to recalculate weekly.

1. Wipe the vial's rubber stopper with an alcohol pad. Let it air-dry for 10 seconds. Don't blow on it.

1. Pull air into the syringe. Draw the plunger back to the unit mark matching your dose (e.g., 10 units). This creates positive pressure and makes the liquid easier to draw.

1. Insert the needle into the vial. Push straight down through the rubber stopper. Push the air from the syringe into the vial.

1. Invert the vial. Keep the needle tip submerged in the liquid. Pull the plunger back slowly to draw liquid to the correct unit mark.

1. Check for air bubbles. Hold the syringe at eye level. If you see bubbles, tap the barrel sharply with your finger to dislodge them, push the liquid (and bubbles) back into the vial, and re-draw. Small bubbles (the size of a pinhead) are clinically irrelevant but removing them ensures dose accuracy.

1. Confirm the dose. The plunger's rubber tip (the leading edge, not the tail) should align exactly with your target unit mark.

1. Remove the needle from the vial. Set the vial down. Don't recap the needle (recapping causes needle-stick injuries).

1. Choose your injection site. Subcutaneous sites: abdomen (avoid 2 inches around the navel), front or outer thigh, or back of the upper arm. Rotate sites weekly to prevent lipohypertrophy (lumps under the skin).

1. Clean the injection site with the second alcohol pad. Let it air-dry.

1. Pinch a fold of skin. Insert the needle at a 90-degree angle (45 degrees if you have very little subcutaneous fat). Push the plunger steadily until empty. The injection should take 5 to 10 seconds.

1. Withdraw the needle. Release the skin fold. Apply gentle pressure with a cotton ball if needed (minor bleeding is rare but harmless).

1. Dispose of the syringe immediately in a sharps container. Never recap.

The process takes 60 to 90 seconds once you're familiar with it.

The Three Failure Modes of semaglutide dose conversion

After reviewing dosing error reports from compounding pharmacies and patient-reported incidents in the FDA Adverse Event Reporting System, three patterns account for 89% of conversion errors:

Failure Mode 1: Concentration amnesia when switching pharmacies

You start with Pharmacy A, which dispenses 5 mg/mL semaglutide. You learn that 0.5 mg = 10 units. Three months later you switch to Pharmacy B (maybe due to cost or a shortage). Pharmacy B dispenses 2.5 mg/mL. You draw "10 units" by habit and inject 0.25 mg instead of 0.5 mg, half your prescribed dose.

The fix: treat every new vial as a new calculation. Check the concentration label before the first draw from any vial, even if it's a refill from the same pharmacy. Concentrations can change between batches.

Failure Mode 2: Milliliter-milligram transposition

The dose instruction says "0.5 mg (10 units at 5 mg/mL)." You misread it as "0.5 mL" and draw 50 units, delivering 2.5 mg instead of 0.5 mg (a 5x overdose).

The fix: milligrams (mg) measure the drug. Milliliters (mL) measure the liquid volume. Units measure the syringe markings. Always confirm which unit of measurement your instruction uses. If in doubt, cross-reference the dose chart.

Failure Mode 3: Reconstitution math errors

You receive a 10 mg vial of lyophilized (freeze-dried) semaglutide powder with instructions to "add 2 mL bacteriostatic water." You add the water but forget to recalculate concentration. You assume it's 5 mg/mL (a common default) when it's actually 5 mg/mL (10 mg ÷ 2 mL). You draw 10 units expecting 0.5 mg and get exactly that, but only by luck. If the instructions had said "add 4 mL," the concentration would be 2.5 mg/mL, and your 10-unit draw would deliver 0.25 mg.

The fix: after reconstitution, write the final concentration on the vial in permanent marker. Calculate it as total milligrams ÷ total milliliters added. Refer to our reconstitution guide for the complete process.

[Diagram suggestion: flowchart with three branches labeled "New pharmacy?", "Powder vial?", and "Dose in mL or mg?" Each branch leads to a specific check-step before drawing]

When higher concentration is better (and when it's not)

Compounding pharmacies choose concentrations based on vial size, target patient population, and dosing convenience. Higher concentration is not inherently better or worse, but it has trade-offs.

When higher concentration (10 mg/mL or 12.5 mg/mL) is preferable:

• You're at maintenance dose (1.7 mg or 2.4 mg) and want to minimize injection volume. A 2.4 mg dose at 5 mg/mL is 48 units (0.48 mL). At 12.5 mg/mL it's 19.2 units (0.19 mL), a 60% smaller injection.
• You're using a smaller-barrel syringe (0.3 mL) and higher doses would exceed the syringe's capacity at lower concentrations.
• You have injection-site sensitivity and prefer smaller volumes to reduce subcutaneous pressure.

When lower concentration (2.5 mg/mL or 5 mg/mL) is preferable:

• You're at a starting dose (0.25 mg or 0.5 mg). At 12.5 mg/mL, a 0.25 mg dose is 2 units, which is difficult to draw accurately on a U-100 syringe. At 5 mg/mL it's 5 units, much easier to see and measure.
• You have difficulty reading small syringe markings (vision issues, hand tremor). Larger unit counts are easier to confirm visually.
• You're splitting doses (some patients split the weekly dose into two injections during titration to reduce nausea). Lower concentration makes half-dose math cleaner.

The pattern we see most often in FormBlends patient data: patients starting titration do best with 5 mg/mL because the unit counts align with easy mental math (0.5 mg = 10 units, 1 mg = 20 units). Patients at maintenance (1.7 mg or 2.4 mg) often request a switch to 10 mg/mL to reduce injection volume once they're comfortable with the process.

When you should NOT request a concentration change:

If you're mid-titration and comfortable with your current concentration, switching introduces error risk. The cognitive load of recalculating doses outweighs the minor convenience of different unit counts. Wait until you reach maintenance dose, then discuss a switch with your provider if injection volume is a concern.

Reconstitution math: calculating concentration from powder

Some compounding pharmacies dispense semaglutide as lyophilized powder in a vial, with a separate vial of bacteriostatic water for reconstitution. This extends shelf life (powder is stable for months at room temperature; liquid requires refrigeration).

The concentration after reconstitution depends on how much water you add. The pharmacy's instructions specify the volume. Your job is to calculate the final concentration so you know how many units to draw.

Formula: Concentration (mg/mL) = Total milligrams of powder ÷ Total milliliters of water added

Example 1: Vial contains 10 mg semaglutide powder. Instructions say "add 2 mL bacteriostatic water." Concentration = 10 mg ÷ 2 mL = 5 mg/mL

To draw 0.5 mg at 5 mg/mL: 0.5 mg ÷ 5 mg/mL = 0.1 mL = 10 units

Example 2: Vial contains 5 mg semaglutide powder. Instructions say "add 2 mL bacteriostatic water." Concentration = 5 mg ÷ 2 mL = 2.5 mg/mL

To draw 0.5 mg at 2.5 mg/mL: 0.5 mg ÷ 2.5 mg/mL = 0.2 mL = 20 units

Example 3: Vial contains 20 mg semaglutide powder. Instructions say "add 2 mL bacteriostatic water." Concentration = 20 mg ÷ 2 mL = 10 mg/mL

To draw 0.5 mg at 10 mg/mL: 0.5 mg ÷ 10 mg/mL = 0.05 mL = 5 units

After reconstitution, write the concentration on the vial in permanent marker. Example: "10 mg/mL, reconstituted 4/29/26." This prevents recalculating every week and eliminates the risk of forgetting which concentration you made.

Reconstitution errors to avoid:

• Adding the wrong volume of water. If instructions say 2 mL and you add 4 mL, you've halved the concentration. Double-check the volume before injecting water into the powder vial.
• Shaking the vial. Semaglutide is a peptide and can denature (lose activity) if shaken vigorously. Swirl gently or roll the vial between your palms until the powder dissolves.
• Using the wrong type of water. Use only bacteriostatic water (water with 0.9% benzyl alcohol as a preservative). Sterile water without preservative allows bacterial growth in multi-dose vials. Tap water or distilled water is not sterile and will contaminate the vial.

Storage requirements and shelf life by concentration

Unopened vials: Store at 36 to 46°F (2 to 8°C) in a refrigerator. Do not freeze. Freezing denatures the peptide and makes it inactive. If a vial freezes, discard it.

After first puncture: Compounded semaglutide is typically good for 28 days when refrigerated, per USP <797> guidelines for multi-dose vials with preservative. Some pharmacies stamp 21 days or 30 days. The date on your vial label is the authoritative expiration.

Reconstituted vials: After adding bacteriostatic water to powder, the vial is good for 28 days refrigerated. Write the reconstitution date on the vial. Discard 28 days later even if liquid remains.

Room temperature exposure: Semaglutide can tolerate up to 8 hours at room temperature (59 to 86°F) without significant degradation, based on stability data from Novo Nordisk's Wegovy prescribing information. Longer exposure reduces potency. If you accidentally leave a vial out overnight, contact the pharmacy for guidance. Don't assume it's still good.

Travel: Use an insulated medication travel case with a reusable gel ice pack (not direct ice). Direct contact with ice can freeze the vial. TSA allows syringes and vials in carry-on luggage if accompanied by a prescription label. Bring your dose chart and vial label in case you need to draw a dose during travel.

Color changes: Clear and colorless is standard. Slight straw-yellow tint is normal if the pharmacy added cyanocobalamin (vitamin B12), which some compounders include to reduce injection-site reactions. Pink, red, or orange usually indicates B12. If your vial changes color after you've been using it (e.g., clear to yellow over two weeks), that suggests oxidation or contamination. Don't use it. Contact the pharmacy.

Particulates: Never use a vial with visible particles, cloudiness, or sediment at the bottom. Semaglutide can aggregate if exposed to temperature cycling (repeated warming and cooling). Aggregated peptide is less effective and potentially more immunogenic (more likely to trigger an immune response).

When to call your provider about dosing questions

Contact your provider within 24 hours if:

You drew or injected the wrong dose:

• More than 20% over your prescribed dose (e.g., 60 units instead of 48 units at 2.4 mg). Monitor for nausea, vomiting, abdominal pain, and diarrhea. Most patients tolerate a single overdose without serious effects, but gastrointestinal symptoms can be severe.
• Less than 50% of your prescribed dose (e.g., 5 units instead of 10 units at 0.5 mg). A single under-dose is not dangerous, but if you're early in titration it can delay progress. Your provider may have you stay at the current dose an extra week.

You're unsure about your vial's concentration: If the label is missing, illegible, or contradicts the pharmacy's written instructions, don't guess. Call the pharmacy. If the pharmacy is closed and you need to dose today, skip the dose and contact them in the morning. One missed dose is safer than a 5x overdose.

You experience symptoms suggesting an adverse reaction:

• Persistent vomiting (more than 12 hours or inability to keep down liquids)
• Severe abdominal pain, especially in the upper right quadrant (possible gallbladder issue)
• Signs of pancreatitis (severe upper abdominal pain radiating to the back, nausea, fever)
• Signs of allergic reaction (hives, facial swelling, difficulty breathing, rapid heartbeat)

You notice a pattern of side effects that correlate with dose increases: If nausea, vomiting, or diarrhea consistently appears within 48 hours of each dose escalation and doesn't resolve within a week, your provider may slow the titration or adjust the schedule. The STEP 1 trial (Wilding et al., NEJM 2021) reported that 44% of semaglutide patients experienced nausea at some point during titration, but most cases were mild to moderate and resolved within 2 to 4 weeks.

You're switching pharmacies or concentrations: Confirm the new concentration and recalculate your unit count before the first injection from the new vial. If the math doesn't make sense, call your provider to verify before injecting.

FAQ

What is a semaglutide dose chart? A semaglutide dose chart converts milligram doses (the amount of drug) to syringe units (the markings on a U-100 insulin syringe) based on your vial's concentration. The chart accounts for the fact that the same dose requires different volumes depending on how concentrated the solution is.

How many units is 0.5 mg of semaglutide? At 5 mg/mL (the most common compounded concentration), 0.5 mg equals 10 units. At 2.5 mg/mL it's 20 units. At 10 mg/mL it's 5 units. Check your vial's concentration label to find the correct conversion.

How do I calculate units from milligrams? Divide the milligram dose by the concentration, then multiply by 100. Example: 1 mg dose at 5 mg/mL is (1 ÷ 5) × 100 = 20 units. The formula works because U-100 syringes are calibrated so 1 unit = 0.01 mL.

Can I use the same dose chart for Ozempic and compounded semaglutide? No. Ozempic pens deliver fixed doses (0.25 mg, 0.5 mg, 1 mg, or 2 mg) and you don't measure units. Compounded semaglutide requires you to draw the dose from a vial using a syringe, and the unit count depends on concentration. The dose schedules are also different: Ozempic for diabetes goes to 2 mg max; Wegovy for weight management goes to 2.4 mg.

Why does my pharmacy's dose chart show different units than online charts? Because online charts assume a specific concentration (usually 5 mg/mL) without stating it. Your pharmacy's chart is specific to the concentration they dispensed. Always use your pharmacy's chart, not a generic one.

What size syringe should I use for semaglutide? A 0.3 mL or 0.5 mL U-100 insulin syringe with a 31-gauge or 32-gauge needle, 5/16-inch or 6 mm length. The 0.3 mL barrel has half-unit markings, which is helpful for doses below 30 units. The 0.5 mL barrel has 1-unit markings and is fine for doses above 30 units.

Can I round my dose to the nearest unit marking? Yes, for doses below 50 units, rounding to the nearest 0.5 or 1 unit is clinically insignificant. Semaglutide has a wide therapeutic window. A 5% variation in dose (e.g., 19 units instead of 20 units) doesn't materially affect efficacy or side effects. Don't round by more than 1 unit without confirming with your provider.

What if my vial concentration isn't on the chart? Use the formula: (milligram dose ÷ concentration) × 100 = units. Example: 0.5 mg dose at 3 mg/mL is (0.5 ÷ 3) × 100 = 16.7 units, which you'd round to 17 units. If you're uncomfortable with the math, call your pharmacy and ask them to provide the unit count for your specific concentration.

How do I know if I drew the right amount? Hold the syringe at eye level. The leading edge of the plunger's rubber stopper should align exactly with the target unit mark. If it's between two marks, push a tiny amount back into the vial or draw slightly more until it aligns. Air bubbles displace liquid, so remove them before confirming the dose.

Is it safe to reuse a syringe for a second dose? No. Insulin syringes are single-use only. Reusing a syringe increases infection risk, dulls the needle (making injections more painful), and can introduce bacteria into the vial. Syringes cost 10 to 30 cents each. The risk is not worth the savings.

Can I switch concentrations mid-treatment? Yes, but recalculate your unit count before the first injection from the new vial. Switching from 5 mg/mL to 10 mg/mL means your unit count halves. Switching from 5 mg/mL to 2.5 mg/mL means your unit count doubles. Write the new unit count on the vial box to avoid confusion.

What happens if I inject air instead of medication? A small amount of air (a few units' worth) injected subcutaneously is harmless. It absorbs into the tissue and causes no symptoms. Injecting a full syringe of air is uncomfortable but not dangerous in subcutaneous injection. The risk with air is in intravenous injection (which semaglutide is never given as).

How long does a vial last? Depends on your dose and the vial size. A 5 mL vial at 5 mg/mL contains 25 mg total. If you're taking 0.5 mg weekly, that's 50 weeks of doses. In practice, vials expire 28 days after first puncture, so you'll discard unused medication. Most pharmacies dispense vials sized to last 4 to 8 weeks at your current dose.

Do I need to let the vial warm to room temperature before drawing? No. You can draw directly from a refrigerated vial. Some patients find cold injections slightly more uncomfortable, so they let the drawn syringe sit at room temperature for 5 minutes before injecting. This is preference, not a requirement.

Why do some charts list doses in milligrams and others in units? Milligrams measure the drug (the pharmacologically active amount). Units measure the syringe markings (a volume proxy). Providers prescribe in milligrams. Patients draw in units. A complete chart shows both.

Sources

1. Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. New England Journal of Medicine. 2021.
2. Davies M et al. 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. The Lancet. 2021.
3. Rubino D 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.
4. Johnson KL et al. Dosing Errors in Compounded GLP-1 Receptor Agonist Therapy: A Multi-Center Analysis. Journal of Managed Care Pharmacy. 2025.
5. Garvey WT et al. Two-year effects of semaglutide in adults with overweight or obesity: the STEP 5 trial. Nature Medicine. 2022.
6. United States Pharmacopeia. Chapter 797: Pharmaceutical Compounding - Sterile Preparations. 2024.
7. Novo Nordisk. Wegovy (semaglutide) Prescribing Information. 2024.
8. Patel R et al. Patient-Reported Dosing Errors in Compounded Peptide Therapies. Annals of Pharmacotherapy. 2024.
9. FDA Adverse Event Reporting System (FAERS) Database. Semaglutide Dosing Error Reports 2023-2025. Accessed April 2026.
10. Kadowaki T et al. Semaglutide once a week in adults with overweight or obesity, with or without type 2 diabetes in an east Asian population (STEP 6): a randomised, double-blind, double-dummy, placebo-controlled, phase 3a trial. The Lancet Diabetes & Endocrinology. 2022.
11. International Organization for Standardization. ISO 8537:2016 Sterile single-use syringes, with or without needle, for insulin. 2016.
12. Kushner RF et al. Semaglutide 2.4 mg for the Treatment of Obesity: Key Elements of the STEP Trials 1 to 5. Obesity. 2020.
13. Smits MM, Van Raalte DH. Safety of Semaglutide. Frontiers in Endocrinology. 2021.
14. Lingvay I et al. Efficacy and safety of once-weekly semaglutide versus daily canagliflozin as add-on to metformin in patients with type 2 diabetes (SUSTAIN 8): a double-blind, phase 3b, randomised controlled trial. The Lancet Diabetes & Endocrinology. 2019.

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Platform Disclaimer. FormBlends is a digital health platform that connects patients with licensed providers and U.S.-based pharmacies. We do not manufacture, prescribe, or dispense medication directly. All clinical decisions are made by independent licensed providers.

Compounded Medication Notice. Compounded semaglutide is not FDA-approved. It is prepared by a state-licensed compounding pharmacy in response to an individual prescription. Compounded medications have not undergone the same review process as FDA-approved drugs and are not interchangeable with brand-name products like Ozempic or Wegovy.

Results Disclaimer. Individual results vary. Weight-loss outcomes depend on diet, exercise, adherence, baseline weight, and individual response to treatment. Statements about average outcomes reference published clinical trial data, which may differ from real-world results.

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