Reference chart
Peptide reconstitution chart: mg/mL and units per dose
By An NayalLast reviewed 2026-09-052 sources
The direct answer
On this page (8)
The three formulas
Nothing on this page is a dose recommendation. It is unit conversion: the peptide mass and the water volume are numbers you already have, and the chart turns them into a mark on a syringe.
| Concentration | = vial mg / water mL |
| Volume to draw | = dose mg / concentration |
| Units to draw | = volume mL x 100 |
One conversion sits underneath all three: 1 mg is 1000 mcg, so a 250 mcg dose is 0.25 mg. Convert to milligrams first and the rest of the math stays in one unit.
Concentration chart: what each mix makes
Read down to your vial size and across to the water you plan to add. The top figure is the concentration in mg/mL. The figure under it is how many micrograms one unit on a U-100 syringe holds at that concentration, which is the number that makes a dose easy to check.
| Vial | + 1 mL water | + 2 mL water | + 3 mL water | + 5 mL water |
|---|---|---|---|---|
| 2 mg | 2 mg/mL20 mcg per unit | 1 mg/mL10 mcg per unit | 0.67 mg/mL6.7 mcg per unit | 0.4 mg/mL4 mcg per unit |
| 5 mg | 5 mg/mL50 mcg per unit | 2.5 mg/mL25 mcg per unit | 1.67 mg/mL16.7 mcg per unit | 1 mg/mL10 mcg per unit |
| 10 mg | 10 mg/mL100 mcg per unit | 5 mg/mL50 mcg per unit | 3.33 mg/mL33.3 mcg per unit | 2 mg/mL20 mcg per unit |
| 15 mg | 15 mg/mL150 mcg per unit | 7.5 mg/mL75 mcg per unit | 5 mg/mL50 mcg per unit | 3 mg/mL30 mcg per unit |
| 20 mg | 20 mg/mL200 mcg per unit | 10 mg/mL100 mcg per unit | 6.67 mg/mL66.7 mcg per unit | 4 mg/mL40 mcg per unit |
| 30 mg | 30 mg/mL300 mcg per unit | 15 mg/mL150 mcg per unit | 10 mg/mL100 mcg per unit | 6 mg/mL60 mcg per unit |
| 50 mg | 50 mg/mL500 mcg per unit | 25 mg/mL250 mcg per unit | 16.67 mg/mL166.7 mcg per unit | 10 mg/mL100 mcg per unit |
The pattern is worth internalising: doubling the water halves the concentration and doubles the units you draw for the same dose. That is the whole lever you have when a dose lands somewhere unreadable on the barrel.
Units per dose, at every concentration
Same math, arranged the way people actually ask for it. Find the concentration your mix made in the first column, then read across to the dose your protocol calls for. The number is units on a U-100 syringe. Anything marked with an asterisk is over 100 units, which does not fit in a 1 mL syringe.
| Concentration | Made by | 100 mcg | 250 mcg | 500 mcg | 1 mg | 2 mg | 2.5 mg | 5 mg | 10 mg |
|---|---|---|---|---|---|---|---|---|---|
| 0.4 mg/mL | 2 mg + 5 mL | 25 | 62.5 | 125, over 100 units, does not fit a 1 mL syringe | 250, over 100 units, does not fit a 1 mL syringe | 500, over 100 units, does not fit a 1 mL syringe | 625, over 100 units, does not fit a 1 mL syringe | 1250, over 100 units, does not fit a 1 mL syringe | 2500, over 100 units, does not fit a 1 mL syringe |
| 0.67 mg/mL | 2 mg + 3 mL | 15 | 37.5 | 75 | 150, over 100 units, does not fit a 1 mL syringe | 300, over 100 units, does not fit a 1 mL syringe | 375, over 100 units, does not fit a 1 mL syringe | 750, over 100 units, does not fit a 1 mL syringe | 1500, over 100 units, does not fit a 1 mL syringe |
| 1 mg/mL | 2 mg + 2 mL +1 | 10 | 25 | 50 | 100 | 200, over 100 units, does not fit a 1 mL syringe | 250, over 100 units, does not fit a 1 mL syringe | 500, over 100 units, does not fit a 1 mL syringe | 1000, over 100 units, does not fit a 1 mL syringe |
| 1.67 mg/mL | 5 mg + 3 mL | 6 | 15 | 30 | 60 | 120, over 100 units, does not fit a 1 mL syringe | 150, over 100 units, does not fit a 1 mL syringe | 300, over 100 units, does not fit a 1 mL syringe | 600, over 100 units, does not fit a 1 mL syringe |
| 2 mg/mL | 2 mg + 1 mL +1 | 5 | 12.5 | 25 | 50 | 100 | 125, over 100 units, does not fit a 1 mL syringe | 250, over 100 units, does not fit a 1 mL syringe | 500, over 100 units, does not fit a 1 mL syringe |
| 2.5 mg/mL | 5 mg + 2 mL | 4 | 10 | 20 | 40 | 80 | 100 | 200, over 100 units, does not fit a 1 mL syringe | 400, over 100 units, does not fit a 1 mL syringe |
| 3 mg/mL | 15 mg + 5 mL | 3.3 | 8.3 | 16.7 | 33.3 | 66.7 | 83.3 | 166.7, over 100 units, does not fit a 1 mL syringe | 333.3, over 100 units, does not fit a 1 mL syringe |
| 3.33 mg/mL | 10 mg + 3 mL | 3 | 7.5 | 15 | 30 | 60 | 75 | 150, over 100 units, does not fit a 1 mL syringe | 300, over 100 units, does not fit a 1 mL syringe |
| 4 mg/mL | 20 mg + 5 mL | 2.5 | 6.3 | 12.5 | 25 | 50 | 62.5 | 125, over 100 units, does not fit a 1 mL syringe | 250, over 100 units, does not fit a 1 mL syringe |
| 5 mg/mL | 5 mg + 1 mL +2 | 2 | 5 | 10 | 20 | 40 | 50 | 100 | 200, over 100 units, does not fit a 1 mL syringe |
| 6 mg/mL | 30 mg + 5 mL | 1.7 | 4.2 | 8.3 | 16.7 | 33.3 | 41.7 | 83.3 | 166.7, over 100 units, does not fit a 1 mL syringe |
| 6.67 mg/mL | 20 mg + 3 mL | 1.5 | 3.8 | 7.5 | 15 | 30 | 37.5 | 75 | 150, over 100 units, does not fit a 1 mL syringe |
| 7.5 mg/mL | 15 mg + 2 mL | 1.3 | 3.3 | 6.7 | 13.3 | 26.7 | 33.3 | 66.7 | 133.3, over 100 units, does not fit a 1 mL syringe |
| 10 mg/mL | 10 mg + 1 mL +3 | 1 | 2.5 | 5 | 10 | 20 | 25 | 50 | 100 |
| 15 mg/mL | 15 mg + 1 mL +1 | 0.7 | 1.7 | 3.3 | 6.7 | 13.3 | 16.7 | 33.3 | 66.7 |
| 16.67 mg/mL | 50 mg + 3 mL | 0.6 | 1.5 | 3 | 6 | 12 | 15 | 30 | 60 |
| 20 mg/mL | 20 mg + 1 mL | 0.5 | 1.3 | 2.5 | 5 | 10 | 12.5 | 25 | 50 |
| 25 mg/mL | 50 mg + 2 mL | 0.4 | 1 | 2 | 4 | 8 | 10 | 20 | 40 |
| 30 mg/mL | 30 mg + 1 mL | 0.3 | 0.8 | 1.7 | 3.3 | 6.7 | 8.3 | 16.7 | 33.3 |
| 50 mg/mL | 50 mg + 1 mL | 0.2 | 0.5 | 1 | 2 | 4 | 5 | 10 | 20 |
* Over 100 units, so it will not fit in a single 1 mL U-100 syringe. Mix the vial with less water, or use a larger barrel. Never assume a number in this table is a dose you should take: it is what the arithmetic gives if your protocol already calls for that amount.
A worked example
A 10 mg vial, 2 mL of bacteriostatic water, and a protocol asking for 500 mcg:
Step 1
Convert the dose
500 mcg / 1000 = 0.5 mg.
Step 2
Concentration
10 mg / 2 mL = 5 mg/mL.
Step 3
Volume to draw
0.5 mg / 5 mg/mL = 0.1 mL.
Step 4
Units to draw
0.1 mL x 100 = 10 units.
Ten units on a U-100 syringe is the first mark past the 5, which is about as easy as a draw gets to verify by eye. The same 500 mcg out of the same vial mixed in 1 mL would be 5 units, and out of 5 mL it would be 25 units. Nothing about the peptide changed; only the water did.
How to read a U-100 syringe
A syringe is marked in volume, not in drug. U-100 means the barrel is scaled for a fluid carrying 100 units per millilitre, which is how insulin is supplied, so the full 1 mL mark is 100 units, half a millilitre is 50 units, and one unit is 0.01 mL. That is the entire relationship:
| Units | Volume | On the barrel |
|---|---|---|
| 1 unit | 0.01 mL | the smallest tick |
| 10 units | 0.1 mL | one tenth of the barrel |
| 50 units | 0.5 mL | the halfway mark |
| 100 units | 1.0 mL | the full barrel |
Two things follow. A unit is never a milligram: how much drug sits in one unit depends entirely on the concentration you made, which is what the second column of the first chart spells out. And a dose that comes to more than 100 units cannot be drawn in one 1 mL syringe, so a number in the tables above with an asterisk is a signal to mix the vial with less water rather than to draw twice.
If you would rather type your own numbers than read them off a grid, the reconstitution calculator runs the same three formulas from this same module, and storage and stability covers how long the vial you just mixed stays good.
Questions people ask
How much water do you mix with peptides?
There is no fixed rule, because the water volume is a choice, not a property of the peptide. Whatever you add sets the concentration: vial mg divided by water mL is mg/mL, and that number decides how many units a given dose comes to. Adding more water makes a weaker solution and a larger, easier-to-measure draw; adding less makes a stronger solution and a smaller draw. Common volumes are 1, 2, 3 and 5 mL of bacteriostatic water, and the chart on this page shows the concentration each one produces for vials from 2 mg to 50 mg. Pick the volume that puts your dose somewhere readable on the syringe rather than down at 2 or 3 units.
How do you reconstitute 30 mg of peptide?
The math, not the protocol: 30 mg in 1 mL of bacteriostatic water is 30 mg/mL, so one unit on a U-100 syringe holds 300 mcg. In 2 mL it is 15 mg/mL and 150 mcg per unit; in 3 mL it is 10 mg/mL and 100 mcg per unit; in 5 mL it is 6 mg/mL and 60 mcg per unit. Once you have the concentration, units to draw is dose mg divided by concentration, times 100. If your protocol calls for 2 mg from a 30 mg vial mixed in 3 mL, that is 2 / 10 = 0.2 mL, which is 20 units.
How do you calculate reconstitution?
Three lines. Concentration in mg/mL is vial mg divided by bacteriostatic water mL. Volume to draw in mL is dose mg divided by that concentration. Units to draw is that volume times 100, because a U-100 syringe carries 100 units to the millilitre. Convert micrograms to milligrams first by dividing by 1000, so a 250 mcg dose is 0.25 mg. If the answer comes out above 100 units it does not fit in a 1 mL syringe, so either split it or mix the vial with less water.
Keep reading
Sources
Every number in the charts is arithmetic, computed at build time from the same module the calculator uses, so there is nothing here to take on trust. These two labels back the two physical facts the math sits on: the U-100 scale and what bacteriostatic water is.
- [1]HUMULIN R (regular insulin human injection, USP) - FDA prescribing information (DailyMed)labelStates the U-100 strength as 100 units/mL and instructs that a syringe marked for U-100 insulin preparations be used. That 100 units per millilitre is the scale every unit figure in these charts is computed on. Accessed 2026-09-05.
- [2]Bacteriostatic Water for Injection, USP - label (DailyMed)labelBacteriostatic water carries 0.9% (9 mg/mL) or 1.1% (11 mg/mL) benzyl alcohol as a bacteriostatic preservative and is supplied in a multiple-dose container from which repeated withdrawals may be made. That is why it is the diluent behind the water volumes charted here. Accessed 2026-09-05.
Pepteca is for education and information only. It does not provide medical advice, diagnosis, or treatment, and its calculators perform unit math only. Always verify with a licensed provider before starting, changing, or stopping any protocol. Many peptides are not approved for human use and may be regulated differently where you live.