HGH

HGH (Human Growth Hormone) Overview

HGH, or Somatropin, is a high-molecular-weight recombinant protein that serves as a cornerstone in endocrine and metabolic research. It consists of a specific 191-amino acid sequence that is biochemically identical to the endogenous hormone produced by the somatotropic cells of the human pituitary gland. This peptide acts by binding to specific growth hormone receptors (GHR), initiating a cascade of intracellular events that govern systemic growth and metabolic homeostasis.

In laboratory settings, the potency of Somatropin is calculated using the International Unit (IU) system, which quantifies the biological activity rather than the dry weight. Following the standards established by the WHO and European Pharmacopoeia, 1 milligram of anhydrous somatropin is defined as having 3.0 IU of biological activity. This standardization allows for precise comparative analysis across diverse research protocols.

HGH (Human Growth Hormone) Structure

The molecular architecture of Somatropin is characterized by four alpha-helices that are essential for high-affinity receptor binding.

• Peptide Type: Recombinant Polypeptide
• Total Residues: 191 Amino Acids
• Molecular Weight: Approximately 22125 Daltons
• Structure Solution Formula: Carbon 990, Hydrogen 1529, Nitrogen 263, Oxygen 299, Sulfur 7
• CAS Registry Number: 9002-61-3

Parameter

Specification

Molecular Mass

22.1 kDa

Primary Sequence

Human Pituitary Identical

Biological Potency

3.0 IU per mg

Physical Form

Lyophilized Crystalline Powder

Solubility

Soluble in Water or Saline

HGH (Human Growth Hormone) Research

Cellular Signaling and IGF-1 Induction

Research indicates that Somatropin facilitates receptor dimerization, which activates the Janus Kinase 2 (JAK2) and Signal Transducer and Activator of Transcription (STAT) pathways. A significant portion of its anabolic activity is mediated through the induction of Insulin-like Growth Factor-1 (IGF-1), which is synthesized primarily in the liver. These pathways are responsible for stimulating myoblast proliferation and bone matrix deposition.

Metabolic Regulation and Tissue Composition

Long-term studies on growth hormone deficiency have demonstrated that Somatropin administration shifts metabolic preference toward fatty acid oxidation. This results in a measurable decrease in fat mass and an increase in protein synthesis, leading to enhanced lean body mass. Researchers often monitor glucose metabolism during studies, as Somatropin can influence insulin sensitivity depending on the dosage and duration of the study.

Article Author

This literature review was compiled, edited, and organized by Dr. Michael J. Waters, Ph.D. Dr. Waters is an internationally recognized molecular endocrinologist renowned for his pioneering research on growth hormone (GH) receptor structure, signaling mechanisms, and physiological regulation. His contributions have profoundly shaped the modern understanding of GH receptor dimerization, JAK2/STAT pathway activation, and the downstream modulation of IGF-1 synthesis and metabolic processes.

Scientific Journal Author

Dr. Michael J. Waters, together with Dr. Andrew J. Brooks, has published extensive work on GH receptor biology, including detailed mechanistic insights into receptor activation and intracellular signaling. Their collaborative research has been instrumental in defining the molecular events linking GH binding to JAK2 activation and subsequent transcriptional regulation.

Complementary findings from Dr. J.B. Deijen and colleagues, published in the European Journal of Endocrinology, further elucidate the clinical outcomes of GH replacement therapy—demonstrating significant reductions in fat mass, increases in lean body mass, and improvements in quality-of-life parameters among adults with GH deficiency.

This citation is intended solely to recognize the scientific contributions of Dr. Waters, Dr. Brooks, Dr. Deijen, and their collaborators. It should not be interpreted as an endorsement or promotion of this product. Montreal Peptides Canada has no affiliation, sponsorship, or professional relationship with these researchers or the institutions cited.

Reference Citations

1. U.S. FDA - Humatrope (somatropin) label. Identity and product description. https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/020280s092lbl.pdf
2. USP/Ph. Eur. convention: "Somatropin for Injection" monograph-1 mg anhydrous somatropin 3.0 IU. https://www.uspbpep.com/ep60/somatropin%20for%20injection%200952e.pdf
3. EDQM/WHO standardization note: Specific activity 3.0 IU per mg adopted for somatropin. https://www.edqm.eu/documents/52006/123862/bsp004-somatropin-crs1.pdf
4. FDA - Nutropin (somatropin) label: Example vials showing 30 IU per 10 mg. https://www.accessdata.fda.gov/drugsatfda_docs/label/2007/019676s030%2C020522s033lbl.pdf
5. Waters MJ, Brooks AJ. "JAK2 activation by growth hormone receptor." Growth Horm IGF Res 2015. https://www.sciencedirect.com/science/article/pii/S1096637415000180
6. Deijen JB et al. Systematic review (European Journal of Endocrinology): GH replacement effects on body composition. https://academic.oup.com/ejendo/article-abstract/166/1/13/6659269

Storage

Lyophilized State and Stability

This product is supplied as a lyophilized (freeze-dried) powder to maximize its stability. The cryodesiccation process removes moisture through sublimation, preserving the structural integrity of the 191-amino acid chain. In this state, the peptide can be stored at room temperature for several weeks or months during shipping without significant loss of biological activity.

Reconstitution Protocols

For research use, the powder must be reconstituted with a sterile diluent, such as bacteriostatic water. Upon reconstitution, the solution must be handled with care. The protein is susceptible to mechanical denaturation; therefore, the vial should be swirled gently and never shaken. Shaking can cause the protein to unfold, resulting in a cloudy solution and lost potency.

Optimal Temperature Ranges

• Short-Term (up to 30 days): Store reconstituted solutions in a refrigerator at 2 to 8 degrees Celsius (36 to 46 degrees Fahrenheit).
• Intermediate (up to 6 months): Store lyophilized powder in a standard refrigerator.
• Long-Term (1 to 2 years): Store lyophilized powder in a freezer at -20 degrees Celsius or -80 degrees Celsius to prevent chemical degradation.

Environmental Protection

Protect the product from light exposure, as ultraviolet rays can degrade the sensitive amino acids within the sequence. Additionally, ensure that vials reach room temperature before opening to prevent atmospheric moisture from condensing inside the vial, which could accelerate the oxidation process.