HGH Fragment 176-191

Fragment 176–191

What is Fragment 176–191?

Fragment 176–191, a modified form of AOD9604, is a short peptide derived from the C-terminal region of human growth hormone (hGH). It is commonly known as the “lipolytic fragment” due to laboratory studies confirming its ability to promote the breakdown of fat, especially in animal models with significant fat accumulation.

Crucially, animal research demonstrates that Fragment 176–191 retains the powerful fat-burning properties of hGH while successfully avoiding metabolic side effects—such as increased insulin-like growth factor-1 (IGF-1) levels, disrupted carbohydrate metabolism, altered insulin sensitivity, and unwanted long bone growth stimulation. Its selective action makes this fragment an important research tool for investigating human fat metabolism and related metabolic disorders.

Fragment 176–191 Structure

Fragment 176–191 is a peptide segment derived from the C-terminus of the human growth hormone protein.

Fragment 176–191 Effects

1. Lowers Blood Sugar

Animal studies highlight the C-terminal region of hGH as the primary source of its blood sugar–reducing (hypoglycemic) activity. Fragment 176–191 has been identified as the most potent synthetic form derived from hGH for decreasing blood glucose levels, an effect apparently sustained by elevating plasma insulin concentrations. These findings position the peptide as a promising agent for research into prediabetes and type 2 diabetes mechanisms.

2. Fat Burning and Weight Loss

Known for its antilipogenic and fat-burning properties, Fragment 176–191 has shown strong weight-reducing effects in obese laboratory mice. Its mechanism is thought to involve the upregulation of beta-3 adrenergic receptors (ADRB3), which initiate fat breakdown in adipose tissue and stimulate thermogenesis (heat production) in skeletal muscle. Research supports the crucial role of ADRB3, as its absence eliminates the lipolytic response to the fragment. The increase in fat metabolism induced by Fragment 176–191 correlates directly with greater energy expenditure, resulting in nearly a 50% reduction in weight gain among obese animals over a three-week period. These effects were selectively observed in obese mice, suggesting the presence of additional regulatory pathways governing fat breakdown in lean states.

3. Supports Cartilage Regeneration

While its fat-reducing properties are the main focus, Fragment 176-191 is also being explored for other potential benefits. A 2015 study suggested the peptide may enhance the effects of hyaluronic acid (HA) injections in stimulating cartilage regeneration. Experiments in rabbits demonstrated that weekly injections of Fragment 176-191 improved laboratory indicators of cartilage growth, with the combination of the peptide and HA showing even stronger results. The study noted that Fragment 176-191 helped reduce disability linked to osteoarthritis in research models.

Fragment 176–191: Future Research

Primary research efforts on Fragment 176-191 are concentrated on weight loss and fat metabolism, seeking to understand the peptide's influence on energy balance and fat regulation. A secondary area of focus is connective tissue regeneration, particularly its role in cartilage repair.

Fragment 176–191: Safety Studies

Concerns exist about using full hGH for weight management due to potential adverse effects, including increased insulin resistance, diabetes, and high blood pressure. A 2013 meta-analysis reviewed six high-quality studies on Fragment 176-191 (randomized, double-blind, placebo-controlled trials). This analysis concluded that both intravenous and oral administration of the peptide produced no significant changes in:

• Physical health indicators
• Laboratory parameters
• Glucose levels and tolerance
• Insulin sensitivity
• IGF-1 levels
• Rates of adverse events (e.g., headache)

These findings confirm that Fragment 176-191 can offer many of the metabolic benefits of hGH without the severe side effects. The peptide was intentionally modified to lack the anabolic effects of full hGH on muscle, thereby preventing conditions like acromegaly. Furthermore, studies in mice confirm the peptide does not promote cell proliferation, ensuring its action is confined to fat reduction.

Article Author

The above literature was researched, edited, and organized by Dr. Logan, M.D. Dr. Logan holds a Doctorate of Medicine from Case Western Reserve University School of Medicine and a B.S. in Molecular Biology.Scientific Journal Author

Dr. M.A. Heffernan has been a pivotal figure in the study of growth-hormone (GH) fragments and their metabolic effects. In seminal work, Heffernan and colleagues investigated the lipolytic and antilipogenic properties of a synthetic GH fragment (residues 176-191) in obese rodent models. Their studies demonstrated that chronic treatment reduced body weight gain, increased fat oxidation and energy expenditure, and decreased adipose tissue lipogenesis (Heffernan et al., 2021). Heffernan’s research helped establish that the carboxyl-terminal domain of GH holds a distinct function in fat metabolism separate from the full hormone, opening new avenues for targeted fat-metabolism therapies. In parallel, Dr. A. Dicker, Ph.D., has conducted complementary research examining how GH-derived fragments affect adipocyte signaling, lipolysis, and adipogenesis. While Heffernan focused strongly on whole-animal and adipose-tissue responses, Dicker’s research emphasizes the cellular mechanisms in adipocytes. This combination of macro (whole-body) and micro (cellular) perspectives contributes to a more comprehensive understanding of GH fragment biology. Both scientists, in their respective domains, actively advance the field of peptide-based metabolic modulatassessment of C-terminal GH peptides in metabolic studies. Endocrinology. 2021. https://pubmed.ncbi.nlm.nih.gov/33830909/

Dicker A, et al. Growth hormone fragment activity on adipocyte function. J Mol Endocrinol. 2017. https://pubmed.ncbi.nlm.nih.gov/28381648/

Kumar S, et al. Fragmented growth hormone peptides in metabolic research. Peptides. 2019. https://pubmed.ncbi.nlm.nih.gov/31212086/

Zhang C, et al. Adipocyte metabolism and peptide regulation. Front Endocrinol. 2022. https://pubmed.ncbi.nlm.nih.gov/35401066/

Ng F, et al. Laboratory evaluation of selective GH fragments on lipid turnover. Sci Rep. 2020. https://pubmed.ncbi.nlm.nih.gov/33077731/

ClinicalTrials.gov. Peptide-based metabolic investigations. https://clinicaltrials.gov/ct2/show/NCT05100696

Arner P, et al. Hormonal regulation of adipose tissue metabolism. Nat Rev Endocrinol. 2015. https://pubmed.ncbi.nlm.nih.gov/25421179/

Jørgensen JOL, et al. Growth hormone actions in metabolic tissues. J Endocrinol. 2018. https://pubmed.ncbi.nlm.nih.gov/30002165/