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Human-limitedTargeted fat-loss fragment of growth hormone

HGH Fragment 176-191

Also indexed as AOD-9604, HGH Frag, Fragment 176-191, HGH 176-191

HGH Fragment 176-191 is a synthetic peptide derived from amino acids 176–191 of the C-terminus of human growth hormone (hGH). It was specifically engineered to retain the lipolytic (fat-burning) properties of hGH while eliminating its growth-promoting and insulin-desensitizing effects. Research, primarily in animal models, suggests it stimulates fat breakdown and inhibits the formation of new fat cells.

Overview

Following subcutaneous administration, the peptide is rapidly absorbed with a short half-life estimated at 30–120 minutes due to proteolytic degradation. It distributes primarily to adipose tissue. Pharmacodynamically, the primary effect is on visceral and subcutaneous adipose depots through the beta-3 AR/cAMP/PKA/HSL axis. Studies in obese Zucker rats and murine models demonstrated significant reductions in total body fat mass without changes in food intake, IGF-1 levels, or lean body mass. Limited Phase II clinical trials (AOD9604) in obese human subjects showed modest but statistically significant reductions in body weight over 12-week periods at doses of 1 mg/day, though results were not replicated sufficiently for regulatory approval.

Proposed mechanism

HGH Fragment 176-191 mimics the action of the C-terminal region of native hGH on adipose tissue by activating beta-3 adrenergic receptors and stimulating hormone-sensitive lipase, promoting lipolysis. Unlike full-length hGH, it does not bind to the hGH receptor in a manner that triggers IGF-1 release or significant anabolic signaling, sparing users from hyperglycemia and growth-promoting side effects. It also inhibits lipogenesis by suppressing acetyl-CoA carboxylase activity, reducing the de novo synthesis of fatty acids.

What the evidence supports

Human data exists but the trials are small, short-term, or not yet replicated.

Graded Human-limited

Human data that exists but is thin: open-label work, single-arm studies, small cohorts, or observational follow-up without randomisation.

Key citations

Representative primary sources, including results that did not favour the compound.

  1. [1]

    Lipolytic action of a fragment of human growth hormone spanning amino acids 176-191

    · Biochemical and Biophysical Research Communications, 220(3):751-755 · 1996

  2. [2]

    AOD9604: An Anti-Obesity Drug with Some Insulin Sensitizing Activities in Zucker Rats

    · Obesity Facts, Karger, DOI: 10.1159/000094904 · 2006

  3. [3]

    The lipolytic effect of a growth hormone fragment with sequence 177-191

    · Biochemistry, 33(16):4845-4851 · 1994

  4. [4]

    Phase II randomized controlled trial of AOD9604 in obese subjects

    · Growth Hormone & IGF Research, Elsevier · 2001

Citation records in this build are illustrative placeholders for the design.

Reference information for research purposes. Not medical advice, and not a recommendation to use any compound. Many entries describe substances that are not approved for human use.

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