Drawing Dose

Also known as: drawing up · loading syringe

Drawing a dose means pulling a measured volume of solution from a vial into a syringe, removing air bubbles, and setting it to the exact mark.

Drawing a dose turns your calculation into a measured volume. The basic steps, as set out in approved peptide instructions such as those for EGRIFTA WR (tesamorelin), are: wash your hands, clean the vial stopper with an alcohol swab, insert the needle straight through the stopper, turn the vial and syringe upside down, pull the plunger slowly past the target mark, turn the vial upright and remove the needle, tap the syringe so air bubbles rise, then push the plunger up to the exact target mark so no air pockets remain.

Each draw should use a new sterile syringe and needle, and the solution should be checked before drawing: it should be clear and free of particles or discoloration.

Why it matters

Air in the syringe takes up space that should hold solution, so a bubble means a smaller dose. With small peptide volumes, small errors are a large share of the dose.

Clean technique protects the whole vial, not just one dose. A multi-dose vial is punctured many times, and the CDC's injection-safety guidance calls for a new sterile syringe and needle each time and aseptic technique whenever medication is drawn up. Good light and a clean, flat work surface, which approved instructions also call for, make the marks easier to read.

How to do it

Calculate your dose in units before you start, and work on a clean, flat, well-lit surface.
Wash your hands and clean the vial stopper with an alcohol swab.
Insert a new sterile needle straight into the stopper, then turn vial and syringe upside down.
Pull the plunger slowly to a little past your target mark.
Turn the vial upright, remove the needle, hold the syringe needle-up and tap to bring bubbles to the top.
Push the plunger up to exactly the target mark, expelling air and excess liquid.
Check the volume again before injecting.

Dose delivered (mcg) = units of liquid in the syringe ÷ 100 × concentration (mcg/mL)

Worked example

At 2500 mcg/mL, a 10-unit draw delivers 10 ÷ 100 × 2500 = 250 mcg. If 1 unit of that space is an air bubble, only 9 units are solution: 9 ÷ 100 × 2500 = 225 mcg, 10% less. Check: 225 ÷ 250 = 0.9.

Common mistakes

Leaving air bubbles in the syringe, which reduces the dose.
Reusing a syringe or needle to enter the vial.
Skipping the alcohol swab on the stopper.
Bending the needle on entry and using it anyway; approved instructions say to use a new syringe.
Lining up the wrong part of the plunger with the mark; approved instructions align the top rim of the plunger with the line.

Sources

Prescribing informationEGRIFTA WR (tesamorelin) for injection - prescribing information and instructions for use. DailyMed, U.S. National Library of Medicine, 2025.
GuidelinePreventing Unsafe Injection Practices. Centers for Disease Control and Prevention, 2024.
Prescribing informationBacteriostatic Water for Injection, USP (Hospira) - prescribing information. DailyMed, U.S. National Library of Medicine, 2019.

Page updated October 3, 2026. How we grade evidence: methodology.

Related Terms

Insulin Syringe

An insulin syringe is a small, fine-needle syringe marked in insulin units; on the common U-100 type, 100 units equals 1 mL.

Units (Insulin Syringe)

Units on an insulin syringe are volume markings; on a U-100 syringe, 1 unit = 0.01 mL and 100 units = 1 mL. They are not a dose by themselves.

Reconstitution

Reconstitution is dissolving a freeze-dried (lyophilized) powder in a measured volume of liquid to make a solution of known concentration for injection.

Concentration (mcg/mL)

Concentration (mcg/mL) is how many micrograms of peptide are in each milliliter of solution; it converts a dose by weight into a volume to draw.

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