How do I convert a peptide dose into insulin syringe units?

Divide the milligrams in the vial by the millilitres of bacteriostatic water to get the concentration in mg/mL. Divide your dose by that concentration to get the volume in mL. Multiply by 100 for units on a standard U-100 insulin syringe. For example, 10 mg in 2 mL is 5 mg/mL; a 2 mg dose is 0.4 mL, which is 40 units.

Does adding more bacteriostatic water change my dose?

No. The amount of peptide in the vial is fixed. Water only changes the concentration, so it changes how many units you draw for the same dose. More water means a larger, easier to read draw of a weaker solution.

How many units is 1 mL on an insulin syringe?

On a standard U-100 insulin syringe, 1 mL is 100 units. On a U-40 syringe, usually veterinary, 1 mL is 40 units. Check the scale printed on your barrel before drawing.

What is the difference between mg and mcg?

1 mg equals 1000 mcg. GLP-1 compounds such as retatrutide, tirzepatide and semaglutide are usually dosed in mg. Repair and growth-hormone peptides such as BPC-157, ipamorelin and sermorelin are usually dosed in mcg.

Is this calculator medical advice?

No. It is a unit-conversion tool. It converts a vial strength and a water volume into a draw volume and a syringe mark. It does not decide what you should take. Most compounds listed are sold for research use only and are not approved for human use.

Peptide calculator

Put in what is in the vial, how much bacteriostatic water you added and the dose you want. Get the exact amount to measure out, in mL and in units. No signup, works on a phone.

IndependentThis site does not sell peptides and is not owned by a vendor. Every other calculator on page one of Google belongs to a shop.

The maths is openThe formula is written out on this page and the code behind it is a single file with an automated test suite .

How it earnsAffiliate links on one clearly marked page, and nowhere else. Never inside the calculator.

ReviewedDose ranges and half-life figures last checked 3 September 2026.

How the maths works

Every reconstitution calculation is the same three steps, and once you have seen them you can check any calculator's answer by hand.

Step one, concentration. Divide the peptide in the vial by the water you added. A 10 mg vial with 2 mL of bacteriostatic water is 10 / 2 = 5 mg per mL.

Step two, volume. Divide your dose by that concentration. A 2 mg dose at 5 mg/mL is 2 / 5 = 0.4 mL.

Step three, units. A standard U-100 insulin syringe holds 100 units in 1 mL, so multiply the volume by 100. 0.4 mL is 40 units, which is the 40 mark on the barrel.

The one that catches people out is U-40 syringes, which are usually veterinary. They hold 40 units in 1 mL, so the same 0.4 mL is 16 units, not 40. Check which scale is printed on your barrel before you draw.

The same 0.2 mL drawn on all three common insulin syringes. The volume is identical; only the number you read off the barrel changes.

How much bacteriostatic water should I add?

There is no single correct amount. The water does not change the dose, only how far along the barrel that dose lands. More water means a bigger, easier-to-read draw of a weaker solution. Less water means a small, concentrated draw that is harder to measure precisely.

The practical rule is to pick a volume that puts your usual dose somewhere between roughly 10 and 50 units, because that part of the barrel is easy to read and small errors matter least. If the calculator tells you to draw 3 units, add more water. If it tells you to draw 90 units, add less.

Whatever you choose, write it on the vial. The number is meaningless a week later if you cannot remember how much water went in, and that is the single most common reason people end up re-dosing wrong.

Common questions

How do I convert a peptide dose into insulin syringe units?: Divide the milligrams in the vial by the millilitres of bacteriostatic water to get the concentration in mg/mL. Divide your dose by that concentration to get the volume in mL. Multiply by 100 for units on a standard U-100 insulin syringe. For example, 10 mg in 2 mL is 5 mg/mL; a 2 mg dose is 0.4 mL, which is 40 units.
Does adding more bacteriostatic water change my dose?: No. The amount of peptide in the vial is fixed. Water only changes the concentration, so it changes how many units you draw for the same dose. More water means a larger, easier to read draw of a weaker solution.
How many units is 1 mL on an insulin syringe?: On a standard U-100 insulin syringe, 1 mL is 100 units. On a U-40 syringe, usually veterinary, 1 mL is 40 units. Check the scale printed on your barrel before drawing.
What is the difference between mg and mcg?: 1 mg equals 1000 mcg. GLP-1 compounds such as retatrutide, tirzepatide and semaglutide are usually dosed in mg. Repair and growth-hormone peptides such as BPC-157, ipamorelin and sermorelin are usually dosed in mcg.
Is this calculator medical advice?: No. It is a unit-conversion tool. It converts a vial strength and a water volume into a draw volume and a syringe mark. It does not decide what you should take. Most compounds listed are sold for research use only and are not approved for human use.

Every calculator and chart on this site

Weight management (GLP-1 family)

Retatrutide calculator Vial, water and weekly dose to syringe units
Tirzepatide calculator The 2.5 to 15 mg ladder, converted
Semaglutide calculator The 0.25 to 2.4 mg ladder, converted
Cagrilintide calculator Amylin analogue, 0.3 to 4.5 mg weekly

Growth hormone axis

HGH (somatropin) calculator IU vials to syringe units
Ipamorelin calculator mcg doses, in mL and units
CJC-1295 (no DAC) calculator No-DAC and DAC, mcg to units
CJC-1295 / Ipamorelin blend calculator The 5 mg + 5 mg blend, per component
Sermorelin calculator Nightly mcg doses to units
Tesamorelin calculator 1 to 2 mg daily, in units
Hexarelin calculator mcg doses to units
IGF-1 LR3 calculator Tiny vials, tiny doses
AOD-9604 calculator 300 mcg daily, in units
MOTS-c calculator 5 to 10 mg, two or three times a week

Repair, skin and blends

BPC-157 calculator mcg doses from a 5 or 10 mg vial
TB-500 calculator Loading and maintenance, in units
BPC-157 / TB-500 blend calculator The Wolverine stack, per component
GHK-Cu calculator Large vials, mg doses
GLOW blend calculator The 70 mg blend, split per component
KLOW blend calculator The 80 mg blend, split per component

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PT-141 calculator 0.5 to 2 mg, as needed
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Epitalon calculator Short courses of 5 to 10 mg
Kisspeptin-10 calculator mcg doses to units
Glutathione calculator Large mg doses, 200 mg/mL solutions

Dosage charts and schedules

Peptide reconstitution chart Concentration for every vial and water combination
Peptide dosing chart Printable unit tables for every compound
Retatrutide titration schedule 2 to 12 mg in units, stage by stage
Tirzepatide titration schedule 2.5 to 15 mg in units, stage by stage
Semaglutide titration schedule 0.25 to 2.4 mg in units, stage by stage
KLOW dosage and frequency chart The 80 mg blend at 2, 3 and 4 mL, both phases
GLOW dosage chart The 70 mg blend, units to each peptide
Wolverine stack dosing chart BPC-157 + TB-500, blend and separate vials
MOTS-c dosage chart 5 and 10 mg vials at three water volumes
Tirzepatide reconstitution chart Every vial size, every water volume, the whole ladder
Retatrutide dosing chart 1 to 12 mg across 10, 20 and 30 mg vials

Tools

Peptide calculator (this page)
Reconstitution calculator How much water to add, and why it matters
mg to units calculator Both directions, any concentration
Bacteriostatic water calculator Pick a volume that lands where you can read it
How to read an insulin syringe U-100 vs U-40, and the 2.5x error
The Protocol Pack Free 25-page printable reference
Where to buy Vendor notes and what to check first
1 mg to units on an insulin syringe The conversion table for every common concentration

Read this before you use the numbers. This is a unit-conversion tool. It converts a vial strength and a volume of bacteriostatic water into a concentration, a draw volume and a mark on an insulin syringe. It does not tell you what to take, whether to take it, or whether a compound is safe for you. Most of the compounds listed here are sold for laboratory research use and are not approved for human use. Nothing on this site is medical advice. Dosing decisions belong with a licensed clinician who knows your history. Always confirm the strength printed on your own vial rather than trusting a preset.