Growth Hormone Secretagogues

Somatropin (rHGH)

Recombinant human growth hormone bioidentical to endogenous 191-aa GH. FDA-approved for GH deficiency, HIV wasting, Turner syndrome, and Prader-Willi syndrome. Stimulates IGF-1, lipolysis, and lean mass accrual directly via GHR receptors.

C990H1529N263O299S7Half-life: ~3-5 hours subcutaneousMolar mass: 22124.00 g/mol

⚠ Research & Educational Use Only. Somatropin (rHGH) is a research chemical documented here for scientific education. All information references peer-reviewed literature and preclinical/clinical study data. Not for human consumption. Not medical advice. Consult a licensed researcher or healthcare professional before any laboratory use.

Medically reviewed by Dr. Amanda Reid, MDWritten by the KnowYourPeptide Research TeamLast updated April 2026
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Key Takeaways
  • Directly activates GH receptors (GHR) without relying on endogenous GH secretion — bypasses pituitary limitations
  • Stimulates liver IGF-1 production, driving anabolic and tissue repair effects downstream
  • Reduces visceral adiposity in GH-deficient adults; approved for HIV-associated wasting (Serostim)
  • Somatropin (rHGH) is not FDA-approved for human use. Prescription drug. Schedule III controlled substance in the US. FDA-approved for specific indications only. Illegal for anti-aging or performance use without a prescription.

Research At a Glance

  • Directly activates GH receptors (GHR) without relying on endogenous GH secretion — bypasses pituitary limitations
  • Stimulates liver IGF-1 production, driving anabolic and tissue repair effects downstream
  • Reduces visceral adiposity in GH-deficient adults; approved for HIV-associated wasting (Serostim)
  • Increases lean body mass and reduces fat mass in hypopituitary and GH-deficient patients
Calculate Somatropin (rHGH) dose

What is Somatropin (rHGH)?

Somatropin is recombinant human growth hormone (rHGH), a 191-amino acid single-chain polypeptide that is bioidentical to the endogenous GH produced by somatotroph cells of the anterior pituitary gland. It is produced via recombinant DNA technology in E. coli or mammalian cell expression systems.

Unlike growth hormone secretagogues (GHSPs like ipamorelin, CJC-1295, or GHRP-2), which stimulate the pituitary to release endogenous GH, somatropin acts directly on peripheral GH receptors (GHR) throughout the body. This means it bypasses pituitary regulation entirely and can achieve pharmacological GH levels regardless of the patient's pituitary function.

Key mechanisms include

  • **Direct GHR activation** → stimulates JAK2/STAT5 signaling in hepatocytes → IGF-1 production
  • **Lipolysis**: GH promotes lipase activity in adipocytes, directly mobilizing triglycerides
  • **Protein anabolism**: GH stimulates amino acid uptake and protein synthesis in muscle
  • **Anti-insulin effect**: GH opposes insulin signaling at skeletal muscle → glucose sparing for the brain

FDA-approved uses include: Adult and pediatric GH deficiency, Turner syndrome, Prader-Willi syndrome, small-for-gestational-age (SGA) children, chronic kidney disease, HIV-associated wasting (Serostim), and short bowel syndrome (Zorbtive).

The relationship between somatropin and the various GHSPs documented in this database is that GHSPs are often preferred in research settings because they work with the body's natural pulsatile GH rhythm and feedback loops, whereas exogenous rHGH suppresses endogenous GH axis activity through GHRH/somatostatin feedback.

Key Research Benefits

Documented effects observed in preclinical and clinical studies on Somatropin (rHGH). See all Growth Hormone Secretagogues peptides for comparison.

Directly activates GH receptors (GHR) without relying on endogenous GH secretion — bypasses pituitary limitations
Stimulates liver IGF-1 production, driving anabolic and tissue repair effects downstream
Reduces visceral adiposity in GH-deficient adults; approved for HIV-associated wasting (Serostim)
Increases lean body mass and reduces fat mass in hypopituitary and GH-deficient patients
Approved for idiopathic short stature and multiple pediatric growth disorders
Supports bone mineral density via IGF-1-mediated osteoblast activation

Side Effects & Risks

Adverse effects reported in the research literature. All data sourced from preclinical and clinical study reports.

Carpal tunnel syndrome and peripheral edema at supraphysiological doses
Increased fasting glucose / insulin resistance — GH opposes insulin at peripheral tissues
Arthralgia and myalgia, particularly at higher doses
Potential for acromegalic features with chronic supraphysiological use (joint overgrowth, organomegaly)
IGF-1 elevation may theoretically promote proliferation in existing cancers
Injection site lipohypertrophy with repeated same-site injections

Dosing Data from the Literature

Doses referenced below are sourced from published preclinical and clinical studies. Use the peptide dose calculator to convert these values to injection volume.

Research Dosing Protocol

In FDA-approved clinical settings, GH deficiency replacement typically uses 0.2-0.6 mg/day (individualized by IGF-1 targeting). Research protocols for body composition use 1-3 IU/day subcutaneously.

FDA-approved GHD replacement: 0.2-0.4 mg/day in adults (titrated to IGF-1) Research anti-aging / body composition: 1-2 IU/day Anti-wasting (HIV): up to 6 mg/day (Serostim approval) Administration: Subcutaneous injection, typically in the evening to align with natural GH peak

Enter your vial size and target dose to get the exact injection volume.

Administration in Research Settings

Standard reconstitution and administration methodology for laboratory research use.

Reconstituted with bacteriostatic water. Administered subcutaneously (abdomen, thigh). Evening injection aligns with the natural nocturnal GH peak. Must be refrigerated after reconstitution.

Explore Further

Quick Reference

Half-Life
~3-5 hours subcutaneous
Molar Mass
22124.00 g/mol
Formula
C990H1529N263O299S7
Legal Status
Prescription drug. Schedule III controlled substance in the US. FDA-approved for specific indications only. Illegal for anti-aging or performance use without a prescription.
Storage
Lyophilized powder: 2-8°C (refrigerated). After reconstitution: 2-8°C for up to 14-28 days depending on formulation.

Research Use Only

This information is for educational research purposes only. This is not medical advice. Consult a qualified healthcare professional.