Peptok
peptides profiled research articles
Weight Loss & Metabolism

Fragment 176-191

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Written by Peptok Research
Reviewed by Medical Advisory BoardLast updated: Jan 2026

Quick Stats

Evidence Strength3/10 (Low)

Based on number and quality of indexed studies

Community Popularity5/10 (Moderate)

Based on search volume and community interest

Legal Status

⚖️ Unregulated (US)

Type

Weight Loss & Metabolism

Route

Injection

Half-life

~15-20 minutes

Medical Disclaimer

This content is for informational and research purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before making decisions about peptide use or any medical treatment. Individual results may vary.

Overview

HGH Fragment 176-191 is a modified form of amino acids 176-191 of the human growth hormone (hGH) polypeptide. It targets fat reduction more directly than hGH itself. Studies suggest it inhibits lipogenesis (fatty acid formation) while boosting lipolysis (fat breakdown).

Quick Summary

  • 🧬
    What it is:HGH Fragment 176-191 is a modified form of amino acids 176-191 of the human growth hormone (hGH) polypeptide.
  • 🎯
    Primary use:Weight Loss & Metabolism applications — see benefits section for details.
  • 📊
    Evidence level:Preliminary — Mostly anecdotal or very early-stage research (0 indexed papers)
  • Bottom line:Very early research phase. Approach with appropriate caution; long-term safety is unknown.

HGH Fragment 176-191 isn't a complete human growth hormone (hGH) molecule. It's a specific segment designed to mimic hGH's fat-burning effects without affecting insulin sensitivity or growth. This targeted action makes it appealing to those seeking Weight Management peptides. While hGH can indirectly lead to fat loss, Fragment 176-191 aims to do so directly.

This fragment, representing the C-terminal region of hGH, has shown in studies to be responsible for hGH's fat-reducing effects. It's designed to be more stable and have a more focused action than full-length hGH.

How HGH Fragment 176-191 Works

HGH Fragment 176-191 primarily works by mimicking the way natural human growth hormone regulates fat metabolism. It doesn't bind to growth hormone receptors throughout the body like hGH does, reducing the potential for unwanted side effects. Instead, it seems to act more selectively on fat cells.

The main mechanism involves stimulating lipolysis, the breakdown of fat, and inhibiting lipogenesis, the formation of new fat. It's believed this happens through the beta-3 adrenergic receptor pathway. Activation of these receptors on fat cells triggers a cascade of events that lead to the release of fatty acids into the bloodstream, where they can be used for energy.

Furthermore, Fragment 176-191 may influence glucose metabolism to a limited extent. By promoting lipolysis, the body becomes more reliant on fat for fuel, potentially sparing glucose stores. This effect is far less pronounced than with hGH, which can impact insulin sensitivity. The peptide does not appear to significantly affect blood sugar levels or insulin resistance at typical dosages.

What the Research Actually Shows

Here's a breakdown of the research surrounding HGH Fragment 176-191 and its purported benefits:

  • Fat Loss:
    • Animal Studies: Many studies have shown fat loss in animals. These studies form the basis for the peptide's use in humans.
    • Human Studies: There are limited human studies, and most are small. Some trials have shown a reduction in abdominal fat in obese individuals. However, results vary. Evidence Grade: Preliminary.
  • Increased Energy Expenditure:
    • Animal Studies: Some animal studies suggest an increase in energy expenditure.
    • Human Studies: There is limited human research on this specific effect. Any increase in energy expenditure is likely tied to fat mobilization and utilization as fuel. Evidence Grade: Preliminary.
  • Anti-Aging Effects:
    • Studies: There is no direct evidence supporting anti-aging effects specifically from HGH Fragment 176-191. While fat loss can contribute to a healthier appearance, this is an indirect effect. Evidence Grade: None.
  • Cartilage Repair
    • Studies: There is no direct evidence supporting cartilage repair effects specifically from HGH Fragment 176-191.
  • Breast Cancer Cell Toxicity Enhancement:
    • Studies: A study published in Drug Design, Development and Therapy in 2022 showed that HGH Fragment 176-191 enhanced the toxicity of doxorubicin-loaded chitosan nanoparticles against MCF-7 breast cancer cells in vitro. This suggests a potential synergistic effect when combined with specific cancer treatments, but this is very preliminary research and does not translate to a cancer treatment on its own. It is important to note this study was performed on cells in a lab, not in living organisms. Evidence Grade: None (in humans).

HGH Fragment 176-191 vs. AOD-9604

AOD-9604 is another modified peptide derived from the C-terminus of hGH, similar to Fragment 176-191. Both are designed for fat loss, but there are subtle differences. Both are Weight Management peptides.

  • Mechanism: Both peptides function by mimicking hGH's lipolytic effects. They both appear to act on the beta-3 adrenergic receptors.
  • Structure: AOD-9604 is a slightly longer peptide sequence.
  • Research: The available research is similar for both. Both have shown promise in animal studies for fat loss, with limited human studies yielding mixed results.
  • Anecdotal Evidence: Anecdotally, some users report that AOD-9604 may be slightly less potent than HGH Fragment 176-191, requiring higher dosages to achieve similar effects. However, individual responses can vary.

The choice between the two often comes down to individual preference and response. Because the research is limited for both, it's difficult to definitively say which is more effective.

The Honest Limitations

The biggest limitation surrounding HGH Fragment 176-191 is the lack of robust human clinical trials. While animal studies have demonstrated fat-loss effects, these findings don't always translate directly to humans.

  • Limited Human Data: Most human studies are small, uncontrolled, or lack a placebo group. This makes it difficult to draw firm conclusions about the peptide's efficacy and safety.
  • Short-Term Studies: Many studies are short-term, lasting only a few weeks or months. The long-term effects of HGH Fragment 176-191 are largely unknown.
  • Dosage Standardization: Optimal dosages haven't been definitively established. The effective dosage range can vary among individuals. You can use a peptide dosage calculator to help determine your dosage.
  • Quality Control: The peptide market isn't tightly regulated. The purity and authenticity of products can vary, making it crucial to source from reputable vendors.

Strategic Stacking for Enhanced Results

HGH Fragment 176-191 is frequently stacked with other peptides to maximize fat loss and overall results. A common strategy involves combining it with a growth hormone-releasing hormone (GHRH) like CJC-1295 and a growth hormone-releasing peptide (GHRP) such as Ipamorelin.

This combination aims to stimulate the body's own production of growth hormone, creating a synergistic effect. The GHRH increases the pulsatile release of GH, while the GHRP amplifies the GH pulse. Fragment 176-191 then works to specifically target fat metabolism.

When stacking, it's vital to carefully consider dosages and potential interactions. Start with low doses and gradually increase as needed, while monitoring for any adverse effects.

Benefits & Evidence

Targeted fat loss without muscle wasting

Moderate Evidence

1 studies · 0 human trials

Improved lipid profiles

Preliminary

1 studies · 0 human trials

No effect on blood sugar or growth

Preliminary

1 studies · 0 human trials

Anti-lipogenic properties

Preliminary

1 studies · 0 human trials

Who Uses Fragment 176-191?

Weight management

Moderate

Supports fat loss and metabolic improvements

Type 2 diabetics (Rx only)

Strong

Improves blood sugar regulation

Obesity management

Strong

Clinically validated for BMI reduction

Not recommended if:

Pregnant or nursing, history of hormone-sensitive cancers, active autoimmune conditions, or pediatric patients. Always consult a physician before starting any peptide protocol.

Dosage Guide

Protocol by Experience Level

ExperienceDoseFrequencyCycleRoute
Beginner250 mcgDaily or EOD4–6 wks, 2 wks offSubQ injection
Intermediate375 mcgDaily4–6 wks, 2 wks offSubQ injection
Advanced500 mcgDaily (split dose)4–6 wks, 2 wks offSubQ injection

Standard Protocol

250-500 mcg/day

Route

Subcutaneous

Half-life

~15-20 minutes

Molecular Weight

N/A

Disclaimer

This information is for educational purposes only. Dosage information is derived from research literature and community reports. Always consult a qualified healthcare provider before using any peptide.

What the Community Reports

Community data coming soon

We're aggregating Reddit discussions for Fragment 176-191.

Safety Profile

Regulatory Status

⚠️ Not FDA approved — for research use. Unregulated in US.

Common

  • Injection site irritation
  • Headache (rare)
  • Lethargy (rare)

Rare

  • Dizziness
  • Headache

Serious

No serious adverse events reported in available literature.

Pregnancy: ❌ Not recommended — no safety dataKnown Interactions: 3 documented stacks
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Research

Mechanism of Action

Fragment of human growth hormone (amino acids 176-191) that stimulates lipolysis and inhibits lipogenesis without affecting IGF-1 levels.

No research papers indexed for this compound yet.

Common Stacks

Peptides frequently combined together for synergistic effects.

AOD-9604

Performance

Commonly combined with AOD-9604 for enhanced outcomes

CJC-1295

Body Composition

Growth hormone secretagogue stack for enhanced recovery and body composition

Ipamorelin

Body Composition

Growth hormone secretagogue stack for enhanced recovery and body composition

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