Calculator

Peptide reconstitution calculator

How to reconstitute peptides: this is mixing math, not a dose. Enter the vial amount, the water you add, and the amount per draw you were given. You get the mark to pull to on your syringe.

Plate 34

Syringe draw

Units on a U-100

U-100

Syringe

mg/ml

From the vial

Mixing math for a vial you already have. Not a dose we recommend.

The short answer

How to reconstitute peptides: this is mixing math, not a dose. Enter the vial amount, the water you add, and the amount per draw you were given. You get the mark to pull to on your syringe. The tool never sets an amount.

Dose

No human dose established here

Every number that produces a draw comes from you. Preset buttons on single-compound pages are amounts printed on approved drug labels or used in published studies, and each one says which. They are not a recommendation.

Arithmetic only. Educational, not medical advice.

Nothing on this page is a protocol to copy.

Vial type

What is in the vial

The amount printed on the label. The whole vial, not per mL.

Bacteriostatic water you add

This changes how strong the mix is, not how much peptide is in the vial. 2 mL is the most common. A standard vial holds about 3 mL. The larger options are for blends and big vials that come in bigger glass.

Amount per draw

Enter the amount you were given. The tool converts it; it never suggests one.

Syringe

Insulin barrels are printed in units, where 100 units is 1 mL. Luer barrels are printed in millilitres. Pick the one in your hand.

0.3 mL insulin (30 units, half-unit marks)

Fill in the vial, the water and the amount per draw to see the result.

How the math works

Concentration, meaning how strong the mix is, equals the vial amount in micrograms divided by the water in milliliters. The volume you draw equals the amount per draw you were given divided by that concentration. Multiply that volume by 100 to get units on a U-100 insulin syringe. Draws per vial is the total micrograms in the vial divided by the amount per draw.

A 3 or 5 mL luer syringe is not printed in units, so the same volume is shown in millilitres instead. The last step is always rounding to a mark that is actually on the barrel you are holding. That step decides whether the answer is something you can measure or something you have to guess.

Three worked examples

The arithmetic written out, step by step, on three vials people actually hold. Every figure here was produced by the same functions the calculator above runs.

A 5 mg tirzepatide vial at 2.5 mg per draw

Vial label: 5 mg of powder.
Bacteriostatic water added: 1 mL.
Amount per draw you were given: 2.5 mg.
Syringe in hand: 1 mL insulin barrel, marked every 2 units.

Put the vial in micrograms5 mg x 1000 = 5000 mcg
Concentration, meaning how strong the mix is, is the vial divided by the water5000 mcg / 1 mL = 5000 mcg per mL, which is 5 mg per mL
A U-100 barrel puts 100 units in 1 mL, so one unit is a hundredth of that5000 / 100 = 50 mcg per unit
Put the draw in micrograms too2.5 mg x 1000 = 2500 mcg
Volume is the draw divided by the concentration2500 mcg / 5000 mcg per mL = 0.5 mL
Convert that volume to marks on the barrel0.5 mL x 100 = 50 units
Draws in the vial5000 mcg / 2500 mcg = 2 full draws, nothing left over

Pull to 50 units on the 1 mL insulin barrel. 50 is an even number of 2-unit marks, so it lands exactly on a printed line with nothing to estimate.

Why 1 mL of water and not 2

With 2 mL of water the same 2.5 mg comes out at 1.0 mL, which is 100 units, the entire 1 mL barrel filled to the top with nothing to spare. It still works, but there is no room for error and no way to draw it on a smaller barrel at all: the calculator reports 1.0 mL as over capacity on a 0.3 mL syringe, because it is.

A 10 mg BPC-157 vial at 250 mcg per draw

Vial label: 10 mg of powder.
Bacteriostatic water added: 2 mL.
Amount per draw you were given: 250 mcg.
Syringe in hand: 0.3 mL insulin barrel, marked every half unit.

Put the vial in micrograms10 mg x 1000 = 10000 mcg
Concentration is the vial divided by the water10000 mcg / 2 mL = 5000 mcg per mL
One unit is a hundredth of the concentration5000 / 100 = 50 mcg per unit
Volume is the draw divided by the concentration250 mcg / 5000 mcg per mL = 0.05 mL
Convert that volume to marks on the barrel0.05 mL x 100 = 5 units
Draws in the vial10000 mcg / 250 mcg = 40 full draws

Pull to 5 units on the 0.3 mL insulin barrel. The half-unit marks mean 5 units lands exactly on a line.

The barrel decides whether this draw is readable at all

The same 0.05 mL on a 1 mL insulin barrel, which is marked every 2 units, is too small for that barrel to show. The calculator snaps it to the nearest real mark, 6 units, and 6 units of this mix delivers 300 mcg. That is 20 percent more than the 250 mcg you entered. Nothing about the vial changed. The syringe did. Also, 40 draws at one a day is 40 days of supply, but the vial must be thrown out after 28 days. So 12 draws would still be in the vial the day it is due to be thrown away.

A KLOW blend vial at 2 mg of GHK-Cu per draw

Vial label: GHK-Cu 50 mg, KPV 10 mg, BPC-157 10 mg, TB-500 10 mg. 80 mg of powder in total.
Bacteriostatic water added: 5 mL.
Amount per draw you were given: 2 mg of the GHK-Cu.
Syringe in hand: 0.3 mL insulin barrel, marked every half unit.

Every component is divided by the same water, so the ratio between them never moves50 : 10 : 10 : 10 before the water, and after it
Concentration of the component driving the draw50000 mcg / 5 mL = 10000 mcg per mL of GHK-Cu
GHK-Cu in one unit10000 / 100 = 100 mcg per unit
Units needed for 2 mg of GHK-Cu2000 mcg / 100 mcg per unit = 20 units, which is 0.2 mL
What the other three carry at that same draw10000 mcg / 5 mL = 2000 mcg per mL, so 20 mcg per unit, so 400 mcg each at 20 units
Total powder in one draw2000 + 400 + 400 + 400 = 3200 mcg, which is 3.2 mg
Draws in the vial5 mL / 0.2 mL = 25 full draws

Pull to 20 units on the 0.3 mL insulin barrel. That is 2 mg of GHK-Cu and 400 mcg each of KPV, BPC-157 and TB-500, in one shot.

What a blend takes away from you

You cannot raise one part without raising all of them. Whoever filled the vial set the ratio. The only lever you have is the size of the draw, and that moves everything together. Also, 0.2 mL on a 3 mL luer barrel is only two marks wide, and the calculator flags it as too small to read. The 0.3 mL insulin barrel is the right tool for this draw, even though a bigger barrel was used to add the water. No blend vial has been tested as a mix in a published study.

Common mistakes

These are the five the calculator checks for. Each one gives a wrong number that looks right, instead of an error you can see.

Reading units off a syringe that is not printed in units

An insulin syringe is marked in U-100 units, where 100 units is 1 mL, and it stops at 1 mL. A 3 or 5 mL luer syringe, the regular kind that is not for insulin, has no units on it at all. It is printed in millilitres: every 0.1 mL on a 3 mL barrel and every 0.2 mL on a 5 mL. Being told to draw 24 units on a luer barrel means reading a number that is not there. The calculator gives the draw in whichever scale is printed on the barrel you pick, and says which one it is.

A draw too small to read on the barrel you chose

Below roughly three tick marks, or 0.02 mL, whichever is larger, you are estimating rather than measuring. On a 1 mL barrel marked every 2 units that floor is 6 units. On a 0.3 mL barrel marked every half unit it is 2 units. The same draw can be perfectly readable on one and guesswork on the other, so the fix is often a finer barrel rather than a different mix. If the vial is not mixed yet, more water spreads the same amount over a longer draw, and the calculator computes the volume that does it.

A draw that does not fit the barrel

A 0.3 mL insulin syringe holds 30 units. If the math asks for 45, no amount of care gets it into that barrel in one pull. This is common with GLP-1 drugs, where a single draw is often most of a millilitre. That is why those calculators open on a 1 mL barrel, not a small one. The calculator names the smallest barrel that actually holds the draw, so you are not left at a dead end.

Mixing so strong that every draw lands between marks

Using very little water makes each draw very small. A small draw on a barrel with widely spaced marks almost never lands on a printed line. The calculator snaps to the nearest real mark, then tells you how far that mark is from what you asked for. If it is off by several percent, a different amount of water usually puts the same amount exactly on a mark, and the calculator will name that amount.

Entering milligrams into a field set to micrograms

This one is not a rounding difference. It is off by a factor of a thousand. Entering 2.5 for a 2.5 mg amount while the field reads mcg asks for 2.5 mcg, and a calculator that simply does the division answers 0 units without complaint. The fields on this site start on the unit the compound is actually labelled in, and they flag the entry when it looks like a slip either way.

Calculators for specific compounds

The same math, set up with the vial sizes and units common for each compound, its half-life (how long the body takes to clear half of it) and a link to its research page. Blend vials (KLOW, GLOW, Wolverine, CJC-1295 / Ipamorelin) open in Blend mode.

Anti-aging

Antioxidant

Cosmetic

Growth Hormone

Healing & Recovery

Hormone

Immune

Longevity

Melanocortin

Metabolic

Muscle & Performance

Nootropic & CNS

Frequently asked questions

How to reconstitute peptides?

Reconstitution means mixing freeze-dried peptide powder with bacteriostatic water, which is sterile water with a preservative. This page is mixing math, not a dose. Enter the vial amount, the water you add, and the amount per draw you were given. You get the mark to pull to on your syringe. The tool never sets an amount. Calculators for single compounds, such as /calculator/bpc-157, fill in common vial sizes.

How does peptide reconstitution work?

Reconstitution means mixing a freeze-dried peptide with bacteriostatic water. The vial strength in milligrams divided by the water in milliliters gives the concentration, meaning how strong the mix is. Divide the amount per draw you were given by that concentration to get the volume to draw.

What does 'units' mean on the calculator?

A standard U-100 insulin syringe is marked in units where 100 units equals 1 mL. The calculator converts the required volume into those units so the number matches the syringe markings. A 3 or 5 mL luer syringe is not marked in units, so for those the calculator reports the draw in millilitres instead.

Does adding more bacteriostatic water change the dose?

It does not change the amount of peptide, only how strong the mix is. More water spreads the same peptide across more liquid. So the same amount takes more units to draw, which can make small amounts easier to measure.

How much bacteriostatic water should I use?

There is no correct answer, only convenient ones. 2 mL is the most common choice and a standard vial holds about 3 mL. The practical test is whether your amount per draw lands on a readable mark on the syringe you own: too little water makes the draw too small to read, too much can make it larger than the barrel holds. Enter a volume, look at the draw the calculator returns, and adjust.

Can I use sterile water instead of bacteriostatic water?

Not for a vial you plan to use more than once. Bacteriostatic water contains 0.9 percent benzyl alcohol, a preservative. That is what lets you put a needle into the vial more than once. Sterile water has no preservative, so a vial mixed with it is for one use only. The 28-day limit this calculator uses assumes a vial with a preservative that is used more than once.

How long does a reconstituted vial last?

The usual default is 28 days in the fridge at 2 to 8 C, kept out of the light. That is the figure from USP 797, a US pharmacy standard, for a vial with a preservative that is used more than once. If the maker or pharmacy label gives a different time, the label wins. The calculator shows the discard date next to the date the vial would run out. With a small amount per draw, the vial often lasts past the limit and some of it gets thrown away.

Which syringe do I need?

Whichever one can read your draw. An insulin barrel in 0.3, 0.5 or 1 mL is right for draws up to 1 mL and reads in units. A 3 or 5 mL luer barrel reads in millilitres. It is the normal tool both for drawing up the bacteriostatic water and for draws larger than a millilitre. Closer marks let you measure a smaller draw. The 0.3 mL barrel is marked every half unit, the 1 mL barrel only every 2 units.

What if my draw lands between two marks?

The calculator rounds to the nearest mark that exists on your barrel and then tells you what that mark actually delivers and how far it is from what you entered. If the gap matters, changing the water volume moves the draw without changing the amount of peptide, and the calculator will name a volume that puts it exactly on a mark.

Does this calculator tell me what dose to take?

No. Every number that produces a draw comes from you. The tool turns an amount you already have into a volume, draws per vial and a discard date. Preset buttons on the single-compound pages are amounts printed on approved drug labels or used in published studies, and each one says which it is. They are there to stop unit mistakes, not to recommend anything.

Does it work for blend vials?

Yes. Switch to Blend mode, enter what each part on the label weighs, and pick one part to set the draw. Every other part follows from the label ratio, and the table shows what each one delivers at that draw. The ratio itself cannot be changed after the vial is filled.

Where to go next

The tracker

Keep the numbers you just worked out: draws logged, vial countdown, discard date and reminders. It stays on your device and needs no account.

Blend vials

What is actually in KLOW, GLOW, Wolverine and the rest, part by part, and what is known about each one on its own.

Half-life reference

How long each compound stays in the body. That is what decides whether a draw is daily, every other day or weekly. The calculator says how much, not how often.

The compound database

The evidence behind each one: what the studies measured, whether in people or animals, and what they did not show.

The peptide dosing guide

A free PDF: one page per peptide, with the source marked on every schedule. Drug label, study, a pattern going around online, or calculator preset.

Educational use only. This database summarizes published research and is not medical advice. Where a dose appears it is a record of what a trial or clinic ran, or what people describe doing, with its source attached. Nothing here is a recommendation for personal use. This calculator does not recommend a dose. It only converts the numbers you enter into a volume. The Longevity Archive does not provide medical advice.