HGH 191AA (Somatropin)

Hormones & fertility FDA-approved drug

Recombinant human growth hormone · also known as Somatropin, Human growth hormone, rhGH, HGH

For reference only — not medical advice. Figures are commonly reported values compiled from published sources and may be wrong or out of date. Many compounds listed are not approved for human use. Talk to a licensed clinician before using any compound.

HGH 191AA refers to somatropin, the 191-residue form of human growth hormone made by recombinant DNA technology. Prescription somatropin products are FDA-approved for pediatric growth failure and several adult and pediatric conditions. Dosing here is expressed in IU, using the standard conversion of about 3 IU per mg.

Commonly reported dosing (10 IU vial)

Reconstituted with 3 mL → 3.333 IU/mL.

Phase	Dose	Volume	U-100 units
Starting About 0.2 mg.	0.6 IU	0.18 mL	18
Standard About 0.5 mg.	1.5 IU	0.45 mL	45
Higher About 0.9 mg, the top of the 8-week chart.	2.7 IU	0.81 mL	81

Frequency: Once daily at bedtime · Half-life: ~3.8 hours after subcutaneous dosing (FDA label)

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Commonly reported dose escalation

Weeks	Dose	Volume	U-100 units
Weeks 1-1	0.6 IU	0.18 mL	18
Weeks 2-2	0.9 IU	0.27 mL	27
Weeks 3-3	1.2 IU	0.36 mL	36
Weeks 4-4	1.5 IU	0.45 mL	45
Weeks 5-5	1.8 IU	0.54 mL	54
Weeks 6-6	2.1 IU	0.63 mL	63
Weeks 7-7	2.4 IU	0.72 mL	72
Week 8+	2.7 IU	0.81 mL	81

Higher steps may need a larger vial or more than one draw. Escalation schedules vary; dosing decisions belong to a licensed clinician.

Commonly reported reconstitution steps

Vials are usually brought to room temperature (about 15-20 minutes) first.
3 mL of bacteriostatic water is added slowly down the inside wall of the 10 IU vial.
The vial is swirled gently until clear, not shaken.
This gives 3.33 IU/mL. Mixed vials are typically labeled with the date and refrigerated.

Storage

Before mixing: Sealed vials are commonly stored refrigerated (2-8 °C) and protected from light, or frozen for long-term storage.

After mixing: Reconstituted solution is commonly kept refrigerated (2-8 °C), protected from light, and not frozen.

Commonly used within 28 days of mixing.

How it works

Somatropin binds GH receptors on liver, muscle, fat and bone, driving IGF-1 production and direct effects on growth, protein synthesis and lipid metabolism. Unlike secretagogues, it supplies GH directly rather than prompting the pituitary to release it.

Researched for

Established in clinical trials for growth failure in children and for adult GH deficiency.
Studied in conditions such as HIV-associated wasting and short bowel syndrome under approved indications.
Studied in healthy adults for body composition changes, where effects are modest and adverse effects (fluid retention, joint pain, glucose effects) are common.

Notes

Approved adult GH-deficiency labels describe starting at about 0.2 mg per day (0.15-0.3 mg) with increases every 1-2 months, a slower escalation than the weekly steps in the reference chart.
Approved products come with their own labeled preparation instructions; the reconstitution figures here apply to research vials.
Only prescription products are the approved versions; the 10 IU vial format is a reference-chart convention.
Reported effects of excess GH include edema, carpal tunnel symptoms, joint pain and reduced insulin sensitivity.