What is bacteriostatic water?

Sterile water containing a small amount of benzyl alcohol, which inhibits bacterial growth so a multi-dose vial stays usable for longer. It’s distinct from sterile water for injection and from saline; use whatever the approved Product Information specifies.

Why does the amount of water change the dose I draw?

The peptide mass in the vial is fixed. Adding more water spreads that same mass through a larger volume, so the concentration falls and you draw a larger volume (more units) for the same dose. Less water means a more concentrated solution and a smaller draw.

What do “units” on an insulin syringe mean?

A U-100 insulin syringe is marked in units where 100 units = 1 mL, so 1 unit = 0.01 mL. The calculator converts your dose into the number of units to draw on the syringe size you selected.

mcg vs mg — what’s the difference?

A milligram (mg) is 1,000 micrograms (mcg/µg). Many peptide doses are described in micrograms, while vials are often labelled in milligrams, so the calculator handles the conversion for you.

Is it safe to obtain peptides online?

In Australia many peptides are prescription-only or unapproved, and products sold online without a prescription are frequently unlawful to supply and have not been assessed by the TGA for quality or safety. This tool is general education and is not advice to obtain or use any substance — speak with a registered health practitioner.

Calculators

Reconstitution maths and peptide-property tools, for health professionals working with lawfully supplied products.

For health professionals · research & education only

These tools are for registered health practitioners working with lawfully prescribed or approved medicines, and for general education. Many peptides are prescription-only or unapproved in Australia, and supplying or self-administering unapproved peptides is unlawful. They perform arithmetic / record-keeping only, make no therapeutic claim, and are not a recommendation to use any substance. The log and stock lists stay in your browser. Always rely on the approved Product Information and your professional judgement.

I understand these tools relate to lawfully supplied products / research, and are not medical advice.

Peptide reconstitution guide

How reconstitution works, step by step. General information only — not medical advice, and not instructions to use any substance.

1
Prepare a clean workspace
Work on a clean, flat surface. Wipe it down, wash your hands, and wipe the rubber stopper of the vial and the top of the bacteriostatic water with a fresh alcohol swab. A sterile field matters as much as the maths.
2
Bring everything to room temperature
Let the bacteriostatic water and the lyophilised (freeze-dried) peptide come to room temperature first. Gather your reconstitution syringe, your insulin syringe, and the alcohol swabs before you start.
3
Add the water slowly
Draw up your chosen volume of bacteriostatic water. Insert the needle into the vial and let the water run slowly down the inside wall of the glass — don’t blast it directly onto the powder. The amount of water you add sets the concentration (the calculator above shows the result).
4
Swirl, never shake
Gently swirl or roll the vial until the powder fully dissolves. Do not shake — agitation can damage fragile peptide chains and create foam. If it doesn’t dissolve in a minute or two, let it sit; most go clear on their own.
5
Store it correctly
Once reconstituted, most peptide solutions are kept refrigerated (typically 2–8 °C), protected from light, and used within a limited window. Always follow the storage directions on the approved Product Information for the specific product.

Answers to common questions

What is bacteriostatic water?: Sterile water containing a small amount of benzyl alcohol, which inhibits bacterial growth so a multi-dose vial stays usable for longer. It’s distinct from sterile water for injection and from saline; use whatever the approved Product Information specifies.
Why does the amount of water change the dose I draw?: The peptide mass in the vial is fixed. Adding more water spreads that same mass through a larger volume, so the concentration falls and you draw a larger volume (more units) for the same dose. Less water means a more concentrated solution and a smaller draw.
What do “units” on an insulin syringe mean?: A U-100 insulin syringe is marked in units where 100 units = 1 mL, so 1 unit = 0.01 mL. The calculator converts your dose into the number of units to draw on the syringe size you selected.
mcg vs mg — what’s the difference?: A milligram (mg) is 1,000 micrograms (mcg/µg). Many peptide doses are described in micrograms, while vials are often labelled in milligrams, so the calculator handles the conversion for you.
Is it safe to obtain peptides online?: In Australia many peptides are prescription-only or unapproved, and products sold online without a prescription are frequently unlawful to supply and have not been assessed by the TGA for quality or safety. This tool is general education and is not advice to obtain or use any substance — speak with a registered health practitioner.