HGH Fragment 176-191 (Frag 17-23) 10mg

Research

Scientific Research on HGH Fragment 176-191 (Somatropin Fragment 176-191)
HGH Fragment 176-191 is a synthetic peptide corresponding to amino acids 176 to 191 of the complete somatropin molecule (hGH 191AA). This segment is located in the C-terminal region of human growth hormone.
Structural studies conducted in the 1980s–1990s suggested that hGH's lipolytic activity might be associated with specific molecular regions distinct from those responsible for its classical anabolic and somatotrophic effects mediated by the GH receptor (GHR). The 176-191 fragment was then synthesized to investigate this hypothesis in experimental models.
It is a 16-amino-acid peptide developed exclusively for research purposes.

Mechanism of Action and Inhibition

Unlike complete somatropin (191 aa), HGH Fragment 176-191:

• Does not significantly activate the classical growth hormone receptor (GHR)
• Does not directly induce hepatic IGF-1 production
• Does not reproduce typical systemic anabolic effects of GH

Proposed mechanism (under investigation):
Experimental models suggest the fragment:

• May modulate lipolysis-associated pathways in adipose tissue
• May increase fatty acid oxidation
• May reduce lipogenesis

Some hypotheses point to possible involvement with:

• Modulation of lipolytic enzymes (e.g., HSL – hormone-sensitive lipase)
• Interference in intracellular pathways associated with triglyceride metabolism

However, the specific molecular receptor for this fragment has not been fully characterized.
No description of relevant direct inhibitory activity exists.

Scientifically Investigated Metabolic Impacts

1. Lipid metabolism
   Preclinical studies demonstrated:

• Increased fat mobilization in animal models
• Potential increase in lipid oxidation
• Adiposity reduction in some experimental models

Importantly, observed effects are less broad than those induced by complete GH.

2. Carbohydrate metabolism

• No consistent evidence of significant blood glucose alteration
• Does not appear to induce insulin resistance as observed with complete GH

3. GH–IGF-1 axis

• No significant IGF-1 increase
• Does not stimulate somatic growth

Investigation in Oncological Models

To date, no robust evidence exists of formal investigation of HGH Fragment 176-191 in oncological models as a therapeutic agent.
Theoretical considerations include:

• Absence of relevant IGF-1 axis stimulation
• Potentially lower proliferative risk compared to complete GH

However, controlled in-depth studies in this area are lacking.

Pharmacokinetic Considerations in Research

Pharmacokinetic data are limited and predominantly preclinical.
General characteristics:

• Experimental subcutaneous or intravenous administration
• Short half-life
• Degradation by systemic peptidases
• Absence of systemic long duration like recombinant GH

Stability depends on laboratory storage and reconstitution conditions.

Other Important Existing Research Relationships

• Investigation of functional separation between GH lipolytic and somatotrophic effects
• Studies on molecular regulation of adipocyte metabolism
• Experimental obesity models
• Structural comparisons between somatropin functional regions
  The 176-191 fragment is primarily used as an experimental tool to study GH structural specificity.

Final Considerations

HGH Fragment 176-191 is a synthetic peptide derived from the C-terminal region of human somatropin, developed to investigate the hypothesis of dissociation between lipolytic effects and growth hormone somatotrophic effects.
Available data suggest it may modulate lipid metabolism-related pathways without significantly activating the classical GH receptor or stimulating IGF-1. However, the literature is predominantly preclinical, and definitive molecular mechanisms remain incompletely elucidated.
Its use remains restricted to experimental research contexts.

References

Ng, F. M., Bornstein, J., Pullan, P., & Lazarus, L. (2000). The lipolytic effects of human growth hormone are located within the 177–191 region of the molecule: studies of a synthetic fragment. Endocrinology, 141(1), 152–158. https://doi.org/10.1210/endo.141.1.7243
Heffernan, M. A., Thorburn, A. W., Fam, B., et al. (2001). GH fragment (176-191) increases fat metabolism and reduces adiposity in rodents. American Journal of Physiology-Endocrinology and Metabolism, 281(4), E786–E792. https://doi.org/10.1152/ajpendo.2001.281.4.E786
Møller, N., & Jørgensen, J. O. L. (2009). Effects of growth hormone on glucose, lipid, and protein metabolism in human subjects. Endocrine Reviews, 30(2), 152–177. https://doi.org/10.1210/er.2008-0027
Isgaard, J., Nilsson, A., Vikman, K., & Isaksson, O. G. P. (1989). Growth hormone regulates the level of insulin-like growth factor-I mRNA in rat liver. Endocrinology, 124(1), 36–41. https://doi.org/10.1210/endo-124-1-36

Important
This material is intended exclusively for scientific and laboratory research use.
It is not intended for human, clinical, or therapeutic use.
Acquisition and handling must follow applicable technical, regulatory, and institutional standards.

Scientific Reviewer
Content reviewed by Dr. Ky H. Le, MD. Dr. Ky H. Le is a family physician in Aiea, Hawaii. He received his medical degree from St. George's University School of Medicine and has been practicing for over 20 years. He has expertise in treating obesity, diabetes, hypertension, and high blood pressure, among other conditions—see all areas of specialization. Dr. Ky H. Le accepts Medicare, Aetna, Humana, Blue Cross, United Healthcare.
Ref.: https://health.usnews.com/doctors/ky-le-371599#expertise