HGH (Somatropin) Dosage Calculator
HGH (Somatropin) (also known as Somatropin) reconstitution and dosage reference — calculate vial concentration, BAC water volume, and exact syringe units below.
Also known as: Somatropin, Genotropin, Humatrope, Norditropin, Saizen, Omnitrope
What is HGH (Somatropin)?
Somatropin is recombinant human growth hormone — a 191-amino-acid polypeptide structurally identical to endogenous pituitary HGH. It is FDA-approved for several conditions, including pediatric growth hormone deficiency, adult growth hormone deficiency, Turner syndrome, idiopathic short stature, AIDS-associated wasting, and short bowel syndrome, and is sold under brand names including Genotropin, Humatrope, Norditropin, Saizen, and Omnitrope. Somatropin is conventionally measured in International Units (IU) at the long-standing clinical convention of approximately 3 IU per milligram. Vials are typically labelled in IU — a 10 IU vial corresponds to about 3.33 mg of somatropin. Reconstituted with bacteriostatic water, it is administered as a daily subcutaneous injection. The compound has a short circulating half-life of two to three hours, with most physiological effects mediated downstream through insulin-like growth factor 1.
| 6 IU | lyophilized powder |
| 10 IU | lyophilized powder |
| 12 IU | lyophilized powder |
| 16 IU | lyophilized powder |
| 24 IU | lyophilized powder |
| 36 IU | lyophilized powder |
| 1 IU | ≈ 10 U-100 units (at 10IU / 1mL) |
| 2 IU | ≈ 20 U-100 units (at 10IU / 1mL) |
| 3 IU | ≈ 30 U-100 units (at 10IU / 1mL) |
| 4 IU | ≈ 40 U-100 units (at 10IU / 1mL) |
How it's typically prepared
Inject bacteriostatic water slowly along the inner wall of the vial and swirl gently — do not shake, since somatropin is a fragile glycoprotein. Refrigerate the reconstituted solution at 2–8 °C; in-use stability is brand-specific and typically falls in the 14- to 28-day range. A U-100 insulin syringe is appropriate because IU values map cleanly to its 100-unit-per-mL scale.
Why growth hormone is dosed in IU
Unlike most research peptides, somatropin is conventionally measured in International Units rather than milligrams. International Units describe biological activity rather than mass, which makes them a more direct indicator of expected effect at the receptor. By long-standing clinical convention, 1 mg of somatropin is treated as approximately 3 IU, so a 10 IU vial corresponds to about 3.33 mg of peptide and a 6 IU vial to roughly 2 mg. Vials are almost always labelled in IU; the calculator above accepts either unit.
Reconstitution is straightforward but the glycoprotein is fragile. Inject bacteriostatic water slowly along the inner wall of the vial, swirl gently, and refrigerate the solution at 2–8 °C. Brand-specific in-use stability windows are typically 14 to 28 days and are documented in each manufacturer's prescribing information. A U-100 insulin syringe is appropriate because IU values map cleanly onto its 100-unit-per-mL scale — a 10 IU vial reconstituted in 1 mL gives 10 units per IU.
Growth hormone reconstitution chart
IU-per-mL concentration and the U-100 insulin-syringe units that correspond to one IU at each common somatropin reconstitution. Use it as a quick cross-check against the calculator above.
| 4 IU in 1 mL | 4 IU/mL · 25 units per IU |
| 6 IU in 1 mL | 6 IU/mL · ≈ 16.7 units per IU |
| 10 IU in 1 mL | 10 IU/mL · 10 units per IU |
| 10 IU in 2 mL | 5 IU/mL · 20 units per IU |
| 12 IU in 1 mL | 12 IU/mL · ≈ 8.3 units per IU |
| 16 IU in 2 mL | 8 IU/mL · 12.5 units per IU |
| 24 IU in 2 mL | 12 IU/mL · ≈ 8.3 units per IU |
| 36 IU in 3 mL | 12 IU/mL · ≈ 8.3 units per IU |
Frequently asked questions
- How many IU is 1 mg of HGH?
- By the standard clinical conversion, 1 mg of somatropin is approximately 3 IU. A 10 IU vial therefore contains about 3.33 mg of somatropin; a 6 IU vial contains roughly 2 mg.
- What size vials does growth hormone come in?
- Common somatropin vial sizes used in research and prescribing literature include 4 IU, 5 IU, 6 IU, 10 IU, 12 IU, 16 IU, 24 IU, and 36 IU. Brand-name pens (Genotropin, Humatrope, Norditropin, Saizen, Omnitrope) are sold in fixed IU presentations.
- How much bacteriostatic water do I add to an HGH vial?
- Manufacturer guidance varies by brand and vial size. Typical reconstitution volumes are 1 mL for a 6–12 IU vial or 1.5–2 mL for larger vials. Always follow the volume specified in your specific vial's prescribing information.
- How many U-100 units is 1 IU of HGH?
- It depends on the reconstitution. A 10 IU vial in 1 mL of BAC water yields a 10 IU/mL concentration, so 1 IU equals 0.1 mL or 10 units on a U-100 insulin syringe. Using 2 mL of BAC water halves the concentration to 5 units per IU.
- What is the difference between IU and mg dosing?
- International Units measure biological activity, while milligrams measure mass. For somatropin specifically, 1 mg is approximately 3 IU. Prescribing labels and reconstitution guides typically use IU; some clinical literature and compounded products use mg.
- How long does a reconstituted HGH vial last?
- In-use stability for refrigerated reconstituted somatropin is brand-dependent. Genotropin, Humatrope, and Norditropin each publish specific in-use periods on their FDA prescribing labels — typically 14 to 28 days at 2–8 °C.
Other GHS peptides
PeptideDose is an educational reference. It is not medical advice and does not replace consultation with a licensed healthcare provider. Doses shown in presets are derived from published protocols and product labels — they are not personal recommendations.