Peptides > hGH Fragment 176-191

hGH Fragment 176-191

HGH Fragment 176-191 is a synthetic fragment derived from natural human growth hormone (hGH). Commonly known as the “lipolytic fragment,” it is renowned for its capacity to enhance fat reduction. This compound has demonstrated its effectiveness in reducing blood sugar levels and supporting the healing of cartilage. Importantly, it achieves these effects without triggering increased long bone growth, elevated IGF-1 levels, or changes in insulin sensitivity.

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1. What Is Fragment 176-191?


2. Fragment 176-191 Peptide Structure


3. Fragment 176-191 Effects


4. Fragment 176-191 Future Research

What Is Fragment 176-191?

Fragment 176-191, which is a modified version of AOD9604, represents a small segment of human growth hormone (hGH) and is often referred to as the “lipolytic fragment.” This moniker stems from its proven ability, as demonstrated in laboratory research using genetically engineered mice with substantial fat deposits, to enhance the process of fat burning. Fragment 176-191 has been the subject of extensive study in animal models due to its unique characteristics. While it retains the fat-burning properties of hGH, it avoids some of the other effects associated with its parent protein, such as increasing levels of insulin-like growth factor-1 (IGF-1), negatively impacting carbohydrate metabolism, affecting insulin sensitivity, promoting excessive long bone growth, and more. These targeted effects make fragment 176-191 a valuable tool for investigating human fat metabolism and hold the potential to serve as a foundation for the development of anti-obesity medications in the future.

Fragment 176-191 Peptide Structure

Sequence: Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe
Molecular Formula: C78H125N23O23S2
Molecular Weight: 1817.12 g/mol
CAS Number: 66004-57-7

Fragment 176-191 Effects

1. Blood Sugar Reduction

Lowering Blood Sugar Levels: Research conducted in animal models has identified the c-terminal end of human growth hormone (hGH) as primarily responsible for its hypoglycemic effects, which involve reducing blood sugar levels. Among at least six distinct fragments derived from this section of hGH, fragment 176-191 has emerged as the most effective synthetic derivative for lowering blood sugar levels. This effect is attributed to the sustained elevation of plasma insulin levels resulting from the peptide’s action. As a result, there is growing interest in exploring the potential use of fragment 176-191 as a treatment for prediabetes and type 2 diabetes.

2. Fat Burning and Weight Loss

Lipolytic Properties: Fragment 176-191 has earned the moniker “lipolytic fragment” due to its remarkable fat-burning and weight loss properties, as evidenced by studies in mice. This action is believed to be mediated through an increase in the production of beta-3 adrenergic receptors (╬▓3-AR or ADRB3). Activation of ADRB3 receptors is known to directly enhance fat burning in adipose tissue and induce thermogenesis in skeletal muscle. Importantly, mice lacking ADRB3 receptors do not exhibit the lipolytic effects associated with hGH or fragment 176-191.

Correlation with Energy Expenditure and Weight Reduction: Research findings indicate a direct relationship between the increased fat burning induced by fragment 176-191 and energy expenditure, leading to a significant reduction in weight gain of nearly 50% in obese animals over a three-week period. It’s worth noting that these weight loss effects were observed primarily in obese mice, while lean mice generally maintained their normal body weight even when exposed to fragment 176-191. This suggests the existence of secondary regulatory pathways for lipolysis that take precedence over ADRB3 function when body weight is near or at the ideal level, prompting further investigation into energy homeostasis mechanisms.

Fragment 176-191 Safety Studies

There is legitimate concern regarding the use of hGH or its derivatives for weight control due to potential unwanted side effects. Long-term exogenous administration of hGH has been associated with various adverse effects, including increased insulin resistance, diabetes, acromegaly, cancer, hypertension (high blood pressure), and edema (swelling).

In 2013, a comprehensive study published in the Journal of Endocrinology and Metabolism analyzed six studies involving fragment 176-191 to assess the prevalence and significance of negative effects linked to this peptide. This study specifically included research that adhered to the rigorous randomized, double-blinded, placebo-controlled model of a phase IIb clinical trial to uphold the highest standards of evidence. The findings indicated that both intravenous (IV) and oral administration of Fragment 176-191, when compared to a placebo, did not result in any changes in:

  1. Physical findings
  2. Laboratory parameters
  3. Glucose levels
  4. Glucose tolerance
  5. Insulin sensitivity
  6. IGF-1 levels
  7. Rates of adverse events (e.g., headaches)

These results from the meta-analysis suggest that fragment 176-191 offers many of the benefits of hGH without the associated negative and often severe side effects. This supports the argument for seeking regulatory approval for the clinical use of fragment 176-191. Furthermore, it provides valuable insights into the regulation of human growth, fat deposition, and energy balance. These findings demonstrate that it is possible to target fat loss without affecting energy balance in other nutrient pathways, paving the way for deeper exploration of human energy regulation and methods to manipulate it.

It’s important to note that while hGH has anabolic effects on muscle, fragment 176-191 was intentionally chosen for its ability to entirely avoid anabolic effects. This selectivity is crucial in ensuring that the peptide specifically achieves targeted lipolytic effects without causing acromegaly or any of the other conditions associated with hGH administration. Research in mice has shown that fragment 176-191 does not stimulate cell proliferation.


Fragment 176-191 Future Research

The primary area of research for fragment 176-191 is in weight loss and lipolysis where significant effort is being expended to learn how the peptide can be used to understand fat metabolism and energy homeostasis. The most active secondary area of research is in connective tissue regeneration, particularly cartilage repair.

Article Author

The above literature was researched, edited and organized by Dr. Logan, M.D. Dr. Logan holds a doctorate degree from Case Western Reserve University School of Medicine and a B.S. in molecular biology.


The product information featured on this website pertains exclusively to in-vitro studies. In-vitro studies, also known as ‘in glass’ studies, are conducted outside of living organisms. It’s important to emphasize that these products do not constitute medicines or drugs and have not received FDA approval for the prevention, treatment, or cure of any medical conditions, ailments, or diseases. It is crucial to note that the introduction of these products into the bodies of humans or animals is strictly prohibited by law.