GHK-Cu Calculator
A vial strength and a water volume give a concentration. A concentration and a syringe give units. Worked for the injectable vial sizes tracked across vendors — not topical GHK-Cu, which has nothing to reconstitute.
Last reviewed: September 21, 2026
Vial strength and water volume give a concentration; a dose then gives the unit mark it corresponds to.
For research purposes only. Always verify calculations independently before use.
On this page
What reconstitution is
Injectable, research-grade GHK-Cu ships from vendors as a lyophilized (freeze-dried) powder sealed in a vial. Reconstitution is the act of dissolving that powder in a liquid — typically bacteriostatic water — which turns a fixed mass of peptide (the vial’s labeled mg content) into a solution with a defined concentration, measurable in volume with a syringe. The mass doesn’t change; only how that mass is distributed through a volume of liquid changes. Topical GHK-Cu — serums and creams — is a different product entirely and ships ready to use; none of this arithmetic applies to it.
Injectable GHK-Cu is not FDA-approved, so there is no manufacturer instruction for reconstituting it. The math below is generic pharmaceutical arithmetic (concentration = mass ÷ volume), the same relationship that governs any lyophilized compound dissolved in a diluent, applied to the vial sizes GHK-Cu is actually sold in. For the compound’s mechanism, evidence base, and the topical-vs-injectable regulatory distinction, see the GHK-Cu profile.
What sizes does injectable GHK-Cu come in?
Two sizes, 50 mg and 100 mg, are each carried by three or more of the vendors tracked here — both with a genuinely deep market. They are listed below with the number of vendors carrying each, read from live price data rather than a list kept by hand, which is why the calculator above offers exactly these as one-tap sizes.
| Vial size | Vendors tracking this size |
|---|---|
| 50 mg | 29 |
| 100 mg | 31 |
The arithmetic, worked
Concentration (mg/mL) equals the vial’s total mg divided by the water volume in mL. Micrograms per syringe unit, on a U-100 syringe (100 units = 1 mL), equals that concentration multiplied by 10. The table below reports both figures at two illustrative water volumes for each tracked size — as a statement of what each volume does to the concentration, not a recommendation of either:
| Vial size | At 1 mL water | At 2 mL water |
|---|---|---|
| 50 mg | 50 mg/mL — 500 mcg/unit | 25 mg/mL — 250 mcg/unit |
| 100 mg | 100 mg/mL — 1000 mcg/unit | 50 mg/mL — 500 mcg/unit |
Doubling the water volume halves the concentration and halves the mcg delivered per unit drawn — the relationship is linear in both directions. The general dosage calculator runs this same arithmetic for any vial size and water volume, including ones outside the table above.
Units to draw, by vial size and dose
Every cell is the U-100 unit mark a given dose comes to, for a given vial strength, at 2 mL of bacteriostatic water. The rows are the two vial sizes three or more tracked vendors carry; the columns are round milligram values spanning the injectable research range — not a schedule, and not the phase-1-then-phase-2 sequence itself. See the GHK-Cu profile for the evidence base and what is and isn’t established.
| Vial | 0.5 mg | 1 mg | 1.5 mg | 2 mg | 2.5 mg |
|---|---|---|---|---|---|
| 50 mg | 2.0 | 4.0 | 6.0 | 8.0 | 10.0 |
| 100 mg | 1.0 | 2.0 | 3.0 | 4.0 | 5.0 |
Figures over 100 are shown in amber: they exceed a 1 mL U-100 barrel at this water volume, so that combination does not fit one syringe. More water lowers the concentration and raises the unit count; less water does the reverse. The calculator above works any vial, volume and dose, in either direction.
What one vial comes to
Both tracked sizes, worked at 2 mL. “Doses per vial” is the vial’s total divided by the dose — how many times that amount is present in the vial, before any loss in handling.
100 mg vial at 2 mL — 50.00 mg/mL
| Dose | Units to draw | Draw volume | Doses per vial |
|---|---|---|---|
| 0.5 mg | 1.0 | 0.01 mL | 200.0 |
| 1 mg | 2.0 | 0.02 mL | 100.0 |
| 1.5 mg | 3.0 | 0.03 mL | 66.7 |
| 2 mg | 4.0 | 0.04 mL | 50.0 |
| 2.5 mg | 5.0 | 0.05 mL | 40.0 |
50 mg vial at 2 mL — 25.00 mg/mL
| Dose | Units to draw | Draw volume | Doses per vial |
|---|---|---|---|
| 0.5 mg | 2.0 | 0.02 mL | 100.0 |
| 1 mg | 4.0 | 0.04 mL | 50.0 |
| 1.5 mg | 6.0 | 0.06 mL | 33.3 |
| 2 mg | 8.0 | 0.08 mL | 25.0 |
| 2.5 mg | 10.0 | 0.10 mL | 20.0 |
What changes the answer
- Water volume. Concentration is inversely proportional to water volume — the table above shows this directly. A larger water volume produces a lower concentration, meaning more units are needed to reach the same mg amount, which can exceed a syringe’s barrel capacity at low concentrations and high mg amounts.
- Vial size. For a fixed water volume, concentration is directly proportional to vial size — a 100 mg vial reconstituted with 1 mL is twice the concentration of a 50 mg vial reconstituted the same way.
- Syringe calibration. Every figure above assumes a U-100 syringe (100 units = 1 mL), the standard for peptide research (see the syringes and injection guide). A different calibration — U-40, for instance — would report a different units figure for the identical physical volume; it does not change the concentration or the mg delivered.
How long does reconstituted GHK-Cu last?
Injectable GHK-Cu is not FDA-approved and has no manufacturer label of any kind — not for the lyophilized powder, and not for a reconstituted solution. Topical GHK-Cu is a different product and is outside what this section covers.
Prof. Peptide has not identified a manufacturer label, published study, or lab document establishing how long reconstituted research-grade GHK-Cu remains stable — this page does not state a duration as fact. Refrigeration (2–8°C) once dissolved is standard practice, reported the same way across research peptides generally, not a figure specific to GHK-Cu’s own stability.
FAQ
What is reconstitution?
Does this apply to topical GHK-Cu too?
Does the water volume change how much peptide is in the vial?
What syringe do the unit figures on this page assume?
Why doesn't this page say how much water to add or what dose to draw?
What if my vial's size isn't in the table below?
How much BAC water for a 50mg GHK-Cu vial?
How much BAC water for a 100mg GHK-Cu vial?
References
- See the GHK-Cu profile for the compound’s evidence base and the topical-vs-injectable regulatory distinction. This page reports arithmetic only and cites no additional source of its own beyond the generic reconstitution relationship (concentration = mass ÷ volume).
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