HGH (Somatropin)
FDA ApprovedSomatropin (recombinant human growth hormone, 191AA)
Recombinant human growth hormone (191 amino acid somatropin), FDA approved for growth hormone deficiency and several other named indications. The reference compound all GH secretagogues are compared against.
Dose
1-3 IU
Route
Subcutaneous injection
Cycle
Typically 3-6 months, some research protocols extend to 12+ months
Storage
Refrigerate at 2-8°C (36-46°F), protected from light.
What is HGH (Somatropin)?
Somatropin is a recombinant form of human growth hormone (hGH) approved by the FDA for the treatment of growth hormone deficiency in children and adults, and several other indications such as Turner syndrome, Prader-Willi syndrome, chronic kidney disease, and for children born small for gestational age who fail to catch up in growth by age 2. It is a 191-amino acid polypeptide hormone that is structurally and functionally identical to endogenously produced human growth hormone. Its primary actions are mediated through the IGF-1 pathway, influencing growth, metabolism, and cell proliferation. In research settings, it is studied for its potential roles in muscle growth, fat reduction, tissue repair, and overall metabolic regulation. While pre-filled pens are a common pharmacy format for FDA-approved somatropin products, in the research-chemical market, it is typically supplied as a lyophilized powder.
Key Benefits
- Direct GH replacement
- Lean mass support
- Recovery and tissue repair
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Molecular Information
Molecular weight
22,124 Da
Length
191 amino acids
Type
Polypeptide hormone
Amino acid sequence
FPTIPLSRLFDNAMLRAHRLHQLAFDTYQEFEEAYIPKEQKYSFLQNPQTSLCFSESIPTPSNREETQQKSNLELLRISLLLIQSWLEPVQFLRSVFANSLVYGASDSNVYDLLKDLEEG IQTLMGRLEDGSPRTGQIFKQTYSKFDTNSHNDDALLKNYGLLYCFRKDMDKVETFLRIVQCRSVEGSCGF
Somatropin is a recombinant human growth hormone with an identical amino acid sequence to naturally occurring human growth hormone (hGH).
Pharmacokinetics
Time to peak
3-6 hours (subcutaneous administration)
Half-life
2.5 h
Time to clear
Approximately 18-24 hours
Genentech, Inc. (2018). Nutropin AQ (somatropin) injection, for subcutaneous use. Full Prescribing Information.
Research Indications
Pediatric GHD
FDA-approved for treating children with inadequate endogenous growth hormone secretion, leading to increased linear growth velocity and final adult height.
Adult GHD
FDA-approved for adults with confirmed GHD, resulting in improvements in body composition (decreased fat mass, increased lean body mass), bone mineral density, and quality of life parameters.
Research Protocols
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Adult Growth Hormone Replacement (Standard) | 0.1-0.3 mg (approximately 0.3-0.9 IU) daily, gradually titrated | Daily | Subcutaneous |
| Lean Mass Support / Fat Loss (Research) | 1-3 IU | Daily, or 5-6 days per week | Subcutaneous |
| Enhanced Recovery / Tissue Repair (Research) | 2-4 IU | Daily, or 5-6 days per week | Subcutaneous |
| Higher Dose Research Protocols (Advanced) | 4-6 IU | Daily, or 5-6 days per week | Subcutaneous |
| Low Dose Pulsatile Administration Mimicry (Research) | 0.5-1 IU | 2-3 times daily (e.g., morning, afternoon, pre-bed) | Subcutaneous |
Administration timing relative to meals or exercise can be considered. Evening administration may more closely mimic physiological pulsatile GH release during sleep, while post-workout administration may leverage growth-promoting effects.
Peptide Interactions
- Use Caution
Corticosteroids
Glucocorticoids may inhibit the growth-promoting effects of somatropin. Dosage adjustments of either agent may be necessary. Evidence from FDA-approved labeling.
- Monitor Combination
Insulin/Oral Hypoglycemics
Somatropin can decrease insulin sensitivity, requiring dose adjustments of insulin or oral hypoglycemic agents. Close monitoring of blood glucose is essential. Evidence from FDA-approved labeling.
- Monitor Combination
Thyroid Hormone
Growth hormone can accelerate the metabolism of thyroid hormones. Individuals with secondary hypothyroidism requiring thyroid hormone replacement should be monitored for changes in thyroid function. Evidence from FDA-approved labeling.
- Use Caution
Estrogen (Oral)
Oral estrogen administration may reduce the response to somatropin by increasing hepatic IGF-1 resistance. Higher somatropin doses may be required. Evidence from FDA-approved labeling.
- Compatible
Androgens
Some research suggests androgens may synergistically enhance muscle anabolism with growth hormone, but this is not an FDA-approved co-administration; caution and monitoring are advised for research purposes.
How to Reconstitute
- 1Gather supplies: Somatropin vial, bacteriostatic water (BW) vial, sterile syringes (e.g., 1 mL insulin syringe), alcohol swabs.
- 2Clean the rubber stoppers of both the somatropin vial and the BW vial with alcohol swabs.
- 3Draw the desired amount of bacteriostatic water (e.g., 1 mL per 10 IU vial, depending on desired concentration) into a sterile syringe.
- 4Slowly inject the BW into the somatropin vial, aiming the needle towards the side of the vial to avoid direct contact with the lyophilized powder.
- 5Do NOT shake the vial. Gently swirl the vial between your palms for a few minutes until the powder is fully dissolved. If stubborn, let it sit in the refrigerator for 15-30 minutes and then swirl again.
- 6Once clear and fully dissolved, the solution is ready for administration. Store the reconstituted solution as directed.
Use bacteriostatic water for reconstitution to maintain sterility and extend shelf life. Gently swirl, do not shake, to avoid damaging the peptide structure.
What to Expect
- Improved sleep quality and duration may be an early subjective effect.
- Changes in body composition, such as increased lean muscle mass and decreased adipose tissue, typically become noticeable after several months of consistent use.
- Enhanced recovery from physical exertion and potential improvement in tissue repair.
- Possible increase in energy levels and overall sense of well-being.
- Potential for mild, transient fluid retention (edema) in the extremities, especially in early stages.
- Some individuals may experience joint discomfort or nerve impingement (e.g., carpal tunnel-like symptoms) at higher research doses.
Side Effects & Safety
- Somatropin can affect glucose metabolism; monitor blood glucose levels, particularly in individuals with a history of diabetes or insulin resistance.
- Higher doses or prolonged administration may lead to symptoms of acromegaly, including enlargement of hands, feet, and facial features, which are generally irreversible.
- Potential for fluid retention, carpal tunnel syndrome, and arthralgia (joint pain), which may be dose-dependent.
- Rare but serious adverse effects reported in FDA labeling include increased risk of malignancy in certain populations (e.g., Prader-Willi syndrome), intracranial hypertension, and pancreatitis.
- Always use sterile practices for reconstitution and administration to prevent infection.
- This product is for research purposes only and not for human consumption or therapeutic use.
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