Research Math Reference
Peptide Reconstitution Chart: Concentration, Syringe Units and the Reverse Conversion
A peptide dosage chart in the only sense a chart can honestly provide one. Three tables: the concentration every common vial size reaches at each bacteriostatic water volume, what a single U-100 syringe unit of that solution contains, and the conversion back the other way from an amount to a syringe reading. Every cell is computed arithmetic. Medibact does not provide medical advice, dosing recommendations, injection instructions, treatment protocols, or human-use guidance.
One equation, read three ways
Every number on this page comes from a single relationship: concentration = vial amount ÷ water volume. The three charts below are that equation solved for each of its parts, because those are the three questions people actually arrive with — what concentration did I just make, what is in one syringe unit of it, and how many units hold a given amount.
The second link in the chain is the one worth internalising, because it is fixed and it is where most arithmetic errors enter: a U-100 insulin syringe puts 100 markings across 1 mL, so one unit is always 0.01 mL regardless of what the vial contains. A syringe measures volume, never milligrams. The same 20-unit marking holds a different amount of peptide in every vial you reconstitute differently, which is why a figure carried over from a previous vial is the single most common way to be out by a factor of two or three.
Worked example
A 10 mg vial, reconstituted with 2 mL of bacteriostatic water. Concentration is 10 ÷ 2 = 5 mg/mL. One unit is 0.01 mL, so one unit holds 5 × 0.01 = 0.05 mg. Going the other way, an amount of 2.5 mg occupies 2.5 ÷ 5 = 0.5 mL, which reads as 50 units. Use 1 mL of water instead and the same vial reaches 10 mg/mL, one unit holds 0.1 mg, and that same 2.5 mg now reads as 25 units — the identical vial and the identical amount, at half the syringe reading.
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Buy at MedibactHow much bacteriostatic water should you add?
This is the question the charts below cannot answer for you, because the volume is a choice rather than a property of the compound. The vial holds what the label says it holds whatever you add; the water only decides how that amount is spread, and therefore how the syringe reads. Four things constrain the choice, and none of them is a dose.
- Resolution. A more dilute solution puts any given amount across more markings, so a one-unit misread costs proportionally less. A 10 mg vial in 1 mL puts 0.5 mg at 5 units, where being one unit out is a 20% error; the same vial in 2 mL puts it at 10 units, where the same slip is 10%.
- The barrel. A U-100 insulin syringe holds 1 mL, so no single withdrawal can exceed 100 units. A concentration low enough to push a routine withdrawal past that is too dilute for the syringe, whatever else it has going for it.
- The vial’s own headroom. Small lyophilised vials are not large containers. The volume has to fit the vial in front of you, which is the practical ceiling long before the arithmetic runs out.
- How long the container stays in use. More water means more withdrawals from one vial, which means it stays in service longer. Multi-dose vial conventions commonly reference a 28-day period after first entry unless the manufacturer specifies otherwise, and that window — not the volume left in the vial — is what governs the end of its working life.
Taken together those give a working rule that is arithmetic rather than advice: pick the volume that lands typical readings somewhere in the 10-to-50-unit band, which is where the markings are easiest to read and a single-unit error is smallest in proportion. Which amount is typical for a given piece of work is set by that compound’s own protocol and documentation, never by this page.
Chart 1 — Concentration (mg/mL)
Concentration for common research vial sizes against the bacteriostatic water volumes most often used. Every cell is vial amount ÷ water volume.
| Vial size | + 0.5 mL | + 1 mL | + 2 mL | + 3 mL | + 5 mL |
|---|---|---|---|---|---|
| 1 mg | 2 mg/mL | 1 mg/mL | 0.5 mg/mL | 0.33 mg/mL | 0.2 mg/mL |
| 2 mg | 4 mg/mL | 2 mg/mL | 1 mg/mL | 0.67 mg/mL | 0.4 mg/mL |
| 5 mg | 10 mg/mL | 5 mg/mL | 2.5 mg/mL | 1.67 mg/mL | 1 mg/mL |
| 10 mg | 20 mg/mL | 10 mg/mL | 5 mg/mL | 3.33 mg/mL | 2 mg/mL |
| 15 mg | 30 mg/mL | 15 mg/mL | 7.5 mg/mL | 5 mg/mL | 3 mg/mL |
| 20 mg | 40 mg/mL | 20 mg/mL | 10 mg/mL | 6.67 mg/mL | 4 mg/mL |
| 30 mg | 60 mg/mL | 30 mg/mL | 15 mg/mL | 10 mg/mL | 6 mg/mL |
| 50 mg | 100 mg/mL | 50 mg/mL | 25 mg/mL | 16.67 mg/mL | 10 mg/mL |
Chart 2 — What one syringe unit contains
Each concentration above, converted into the amount of peptide sitting in a single U-100 unit. Multiply by ten for a 10-unit marking, by twenty for a 20-unit marking, and so on — the relationship is linear.
| Vial size | + 0.5 mL | + 1 mL | + 2 mL | + 3 mL | + 5 mL |
|---|---|---|---|---|---|
| 1 mg | 20 mcg / unit | 10 mcg / unit | 5 mcg / unit | 3.3 mcg / unit | 2 mcg / unit |
| 2 mg | 40 mcg / unit | 20 mcg / unit | 10 mcg / unit | 6.7 mcg / unit | 4 mcg / unit |
| 5 mg | 0.1 mg / unit | 50 mcg / unit | 25 mcg / unit | 17 mcg / unit | 10 mcg / unit |
| 10 mg | 0.2 mg / unit | 0.1 mg / unit | 50 mcg / unit | 33 mcg / unit | 20 mcg / unit |
| 15 mg | 0.3 mg / unit | 0.15 mg / unit | 75 mcg / unit | 50 mcg / unit | 30 mcg / unit |
| 20 mg | 0.4 mg / unit | 0.2 mg / unit | 0.1 mg / unit | 67 mcg / unit | 40 mcg / unit |
| 30 mg | 0.6 mg / unit | 0.3 mg / unit | 0.15 mg / unit | 0.1 mg / unit | 60 mcg / unit |
| 50 mg | 1 mg / unit | 0.5 mg / unit | 0.25 mg / unit | 0.17 mg / unit | 0.1 mg / unit |
Amount per unit = concentration × 0.01. Figures below 0.1 mg are shown in micrograms for readability; 1,000 mcg = 1 mg.
Chart 3 — Amount to syringe units
The conversion in the other direction: given a concentration, the syringe reading that holds a particular amount. Units = (amount ÷ concentration) × 100.
The amounts across the top are units of measurement, not suggestions. They are a spread of round figures chosen to make the conversion readable. Which amount applies to any particular piece of work is determined by that compound’s own protocol and documentation, and never by this page.
| Concentration | 0.1 mg | 0.25 mg | 0.5 mg | 1 mg | 2 mg | 2.5 mg | 5 mg |
|---|---|---|---|---|---|---|---|
| 1 mg/mL | 10 u | 25 u | 50 u | 100 u | 200 u | 250 u | 500 u |
| 2 mg/mL | 5 u | 13 u | 25 u | 50 u | 100 u | 125 u | 250 u |
| 2.5 mg/mL | 4 u | 10 u | 20 u | 40 u | 80 u | 100 u | 200 u |
| 5 mg/mL | 2 u | 5 u | 10 u | 20 u | 40 u | 50 u | 100 u |
| 10 mg/mL | 1 u | 2.5 u | 5 u | 10 u | 20 u | 25 u | 50 u |
A reading above 100 units does not fit on a single U-100 syringe — that combination of concentration and amount implies more than 1 mL. Reading down any column shows the fix: a higher concentration puts the same amount into fewer units.
Every chart here assumes a U-100 syringe — what changes if yours is not
The “U” number is markings per millilitre, and it is the one input to this arithmetic that is printed on the barrel rather than chosen by you. U-100 puts 100 markings across 1 mL, so one unit is 0.01 mL. U-40 puts 40 across the same millilitre, so one unit is 0.025 mL — two and a half times the volume at the identical marking. The two barrels look alike, the scales are printed the same way, and nothing about a reading taken on the wrong one looks wrong. U-40 syringes are still sold for veterinary insulin, which is how they reach a bench that assumed U-100.
| Volume drawn | Reads on a U-100 barrel | Reads on a U-40 barrel |
|---|---|---|
| 0.1 mL | 10 u | 4 u |
| 0.2 mL | 20 u | 8 u |
| 0.25 mL | 25 u | 10 u |
| 0.5 mL | 50 u | 20 u |
| 1 mL | 100 u | 40 u |
Barrel capacity is a different variable and a harmless one. The 0.3 mL, 0.5 mL and 1 mL insulin syringes in common use are all U-100 — 30, 50 and 100 units respectively — so a unit is 0.01 mL on all three and every chart on this page applies unchanged. The only thing capacity changes is the largest single withdrawal that fits, and the fact that smaller barrels often carry half-unit gradations, which is the case for reading small amounts on a narrow scale.
“Dosage chart”, “mixing chart”, “cheat sheet” — three different things
Those phrases are used interchangeably in search and they are not interchangeable in practice. Separating them is the fastest way to end up on the right page:
- Concentration and unit conversion — what a vial reaches at a given water volume and what a syringe marking then holds. That is this page, and it is arithmetic that holds for every compound, because it is arithmetic about the solution rather than about the molecule.
- Per-compound supply figures — the vial sizes a particular compound is actually sold in, and the concentrations those reach. That is compound-specific and lives on the 52 calculator pages indexed below, alongside the guide page for each compound.
- How much of a compound to use — a protocol question, and the one this site does not answer. It is also the one a single chart is least able to answer: a table covering twenty compounds in one grid is claiming a uniformity the underlying literature does not have, since the published human record differs compound by compound and for a good number of research peptides does not exist at all.
Medibact supplies bacteriostatic water and publishes reference material. It does not provide dosage recommendations, injection instructions, route or frequency guidance, treatment protocols, or medical advice, and no table on this page should be read as any of those.
Three things that go wrong in this arithmetic
- Carrying a syringe reading across from a different vial. The reading is only valid for the concentration it was worked out at. A 5 mg vial and a 10 mg vial reconstituted with the same water are a factor of two apart at every marking, and the syringe cannot tell you which one you are holding.
- Mixing milligrams and micrograms mid-calculation. Many research compounds are described in mcg and supplied in mg. There are 1,000 mcg in 1 mg, so a slip here is a hundred- or thousandfold error rather than a small one — which is exactly the class of mistake that does not look wrong on the syringe.
- Assuming a millilitre of water displaces nothing. These charts treat the final volume as the water added, which is the standard simplification and is close enough for a lyophilised powder in the quantities involved. It is a simplification nonetheless, and worth knowing you are making it.
The reconstitution calculator covers vial sizes and water volumes these tables do not list, and the worked examples page steps through the same arithmetic longhand.
Per-compound charts
The tables above are generic by design. Each compound below has its own calculator page built around the vial sizes it is actually supplied in, which is more precise than reading off a generic grid — 52 in total.
Continue with related education pages
FAQ
How do you read a peptide reconstitution chart?
Find your vial size down the left, then read across to the volume of bacteriostatic water you added. The cell is the concentration in mg/mL, which is simply vial amount ÷ water volume. A 10 mg vial with 2 mL of water lands on 5 mg/mL. Everything else — how many syringe units a given amount occupies — follows from that one number.
How many mg is one unit on an insulin syringe?
That depends entirely on the concentration, which is why there is no single answer. A U-100 syringe measures volume: one unit is always 0.01 mL. So one unit of a 5 mg/mL solution contains 0.05 mg, while one unit of a 10 mg/mL solution contains 0.1 mg — the same marking, twice the peptide. The second chart on this page gives the per-unit amount for every vial-and-water combination.
How do I convert an amount into syringe units?
Divide the amount by the concentration to get a volume in millilitres, then multiply by 100, because a U-100 syringe puts 100 markings on 1 mL. At 5 mg/mL, 2.5 mg is 0.5 mL, which reads as 50 units. The third chart on this page does that conversion across common concentrations. Which amount applies to any given piece of work comes from that compound's own protocol and documentation, never from this page.
Does a peptide dosage chart tell me how much to take?
No, and no chart on this page does. These are conversion tables between vial amount, water volume, concentration and syringe markings — the arithmetic of the solution, not a recommendation. Medibact does not provide dosage recommendations, injection instructions, route or frequency guidance, treatment protocols, or medical advice.
Why does adding more bacteriostatic water change the chart?
Because concentration is amount divided by volume, and only the volume is changing. The vial still holds the same milligrams; spreading them through 3 mL instead of 1 mL cuts the concentration to a third, so any given amount then occupies three times the volume and three times the syringe units. Reading across any row of the chart shows exactly that.
Does the water volume affect how long the vial lasts?
It affects how many withdrawals the vial yields, not how long the compound remains stable. Stability is a property of the compound and its documentation. What the diluent contributes is the after-entry window on the container: multi-dose vial conventions commonly reference a 28-day period after first entry unless the manufacturer specifies otherwise, and the benzyl alcohol preservative in bacteriostatic water is what makes any defined window possible.
Is there a chart for a specific peptide?
Yes. Each compound in the calculator set has its own page with a concentration table and syringe unit chart built around the vial sizes that compound is actually supplied in, which is more precise than the generic chart here. The full index is on this page.
Why do some cells show mcg instead of mg?
Only for readability. Below 0.1 mg the figure is shown in micrograms so the column does not become a row of leading zeros. 1,000 mcg is 1 mg; the arithmetic is unchanged, and mixing the two units mid-calculation is one of the most common sources of a hundredfold error.
How much bacteriostatic water should I add to a 10 mg vial?
There is no correct volume, because the volume is a choice rather than a property of the compound — the vial holds 10 mg whatever you add. What the choice sets is the resolution you read at: 1 mL makes 10 mg/mL and puts 0.5 mg at 5 units, while 2 mL makes 5 mg/mL and puts the same 0.5 mg at 10 units, where a one-unit misread costs half as much in proportion. The constraints are the barrel (a U-100 syringe holds 1 mL, so no single withdrawal can exceed 100 units), the vial's own headroom, and the fact that more water means more withdrawals and therefore a longer working life for a container whose after-entry window is limited.
What happens if I use a U-40 syringe instead of a U-100?
Every unit figure on this page is 2.5 times wrong. The U-number is markings per millilitre: a U-100 syringe puts 100 markings on 1 mL, so one unit is 0.01 mL, while a U-40 syringe puts 40 on the same millilitre, so one unit is 0.025 mL. The two barrels look alike and the scales are printed the same way, so a reading worked out on one and drawn on the other produces no visible warning at all. U-40 barrels are still sold for veterinary insulin, which is how they turn up. Check the U-number printed on the barrel before using any chart, this one included.
Is there a printable or PDF version of this chart?
The page itself is the reference and prints as it stands — there is no gated download, no email capture and no PDF to request. That is deliberate: a PDF saved once goes stale in a folder, while the charts here are computed from the arithmetic on every page load and the per-compound pages are kept current with the vial sizes each compound is actually supplied in.
How many withdrawals does one vial give?
Total volume divided by the volume of one withdrawal, and nothing more complicated than that. A 10 mg vial in 2 mL of bacteriostatic water is 5 mg/mL; a 0.5 mg withdrawal is 0.1 mL, so the vial holds twenty of them on paper. On paper is the qualifier — residual volume in the vial and in the needle hub means the last withdrawal is usually short, and how long the container remains suitable for use is a separate question from how much liquid is left in it.
Do these charts work for a blend of two compounds in one vial?
The volume arithmetic is unchanged, but the concentration column stops describing one thing. A vial containing two compounds reconstituted into 2 mL gives each of them its own mg/mL, computed separately against the same volume, so one syringe reading delivers two different amounts at once and the chart's single concentration figure no longer applies to either. Work each compound out on its own line against the shared water volume.
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Buy at MedibactEducational use only — not medical advice. This page summarizes information reported in published research and community practice for educational purposes. It is not medical advice and not a recommendation to use any compound. Any doses, schedules, or combinations shown are examples of what has been reported, not instructions for you. Many peptides described here are research compounds that are not FDA-approved for the uses discussed and may be investigational or restricted. Effects, risks, and legal status vary; individual needs and results vary. Consult a qualified, licensed healthcare professional before making any decision. Do not use this content to diagnose, treat, or dose yourself.