The math for this vial
- Concentration: 100 mg ÷ 3 mL = 33.333 mg/mL (33,333.3 mcg/mL).
- Volume of one U-100 unit: 1 ÷ 100 = 0.01 mL.
- Mass in one unit: 33,333.3 mcg/mL × 0.01 mL = 333.3 mcg.
- The whole vial is 300 U-100 units of solution, more than one 1 mL syringe holds.
On a U-40 syringe each unit is 0.025 mL, so each unit holds 2.5 times as much: 833.3 mcg at 3 mL. See U-100 vs U-40 units.
Unit chart
What common U-100 readings hold from a 100 mg vial, by water volume.
| Units | mL | 2 mL water | 3 mL water | 5 mL water |
|---|---|---|---|---|
| 1 | 0.01 | 500 mcg | 333.3 mcg | 200 mcg |
| 5 | 0.05 | 2.5 mg | 1.667 mg | 1 mg |
| 10 | 0.1 | 5 mg | 3.333 mg | 2 mg |
| 20 | 0.2 | 10 mg | 6.667 mg | 4 mg |
| 25 | 0.25 | 12.5 mg | 8.333 mg | 5 mg |
| 50 | 0.5 | 25 mg | 16.667 mg | 10 mg |
| 100 | 1 | 50 mg | 33.333 mg | 20 mg |
About this vial size
100 mg is the largest common GHK-Cu vial. Across the water volumes above, one U-100 unit holds between 200 mcg (at 5 mL) and 500 mcg (at 2 mL). Compared with a 50 mg vial at the same water volume, it is 2 times as concentrated, so the same mass takes 0.5 times the units.
At 50 mg in 3 mL the solution is about 16.7 mg/mL, so a single U-100 unit holds about 167 mcg. Small reading errors are large mass errors at this strength. More diluent spreads the same mass over more graduations.
Storage and handling
- No approved label or validated in-use stability data exists for injectable GHK-Cu. Copper complexes can be sensitive to light and to pH.
- General practice: sealed vials cold and dark; reconstituted solution refrigerated (2-8 °C), unfrozen, labeled.
GHK-Cu is a common topical cosmetic ingredient. Injectable GHK-Cu is not an approved drug, and its compounding status depends on FDA's bulk substance categories.