CalcMyPeptide
Fat LossAlso known as: AOD-9401, Fragment 176-191, Frag

HGH Fragment 176-191

HGH Fragment 176-191 is an isolated, C-terminal snippet of the human Growth Hormone molecule, definitively engineered to isolate hGH's profound fat-burning capability. Essentially a concentrated lipolytic engine, it entirely strips away the growth-promoting and diabetogenic components of the parent hormone. Clinically and athletically favored over full-sequence hGH, it rapidly forces visceral and subcutaneous adipocytes to release stored triglycerides into the bloodstream, achieving dramatic fat reduction without causing insulin resistance, organomegaly, or unwanted bone growth.

Reviewed by CalcMyPeptide Editorial Team
Last updated: April 2026Evidence: Moderate2 peer-reviewed citations

Quick Stats

Half-Life~30 minutes
Dose Range250-500 mcg/day
Frequency1-2× daily (fasted)
Vial Sizes2 mg, 5 mg
BioavailabilitySubcutaneous injection (fasted state)
Year Developed1976

Scientific Data

Molecular Formula
C78H125N23O23S2
Molecular Weight
1817.1 g/mol
CAS Number
PubChem ID
Developer
Monash University (developed from hGH research)

Mechanism of Action

HGH Fragment 176-191 is a truncated analog of human growth hormone consisting of amino acids 176-191 from the C-terminal region. This specific fragment retains the fat-burning activity of HGH without the growth-promoting, diabetogenic, or IGF-1-raising effects.

The fragment stimulates lipolysis (fat breakdown) by mimicking the way natural growth hormone regulates fat metabolism through the beta-3 adrenergic receptor. It also inhibits lipogenesis (new fat formation). Unlike exogenous HGH, it does not compete with human growth hormone receptors and does not induce insulin resistance, making it metabolically safer for dedicated fat-loss protocols.

Source: PMID: 11713213

Background & History

HGH Fragment 176-191 is the C-terminal fragment of human growth hormone. Originally identified by researchers studying which region of hGH drives lipolysis, Frank and colleagues showed the 176-191 region contains the lipolytic activity while the 1-43 region drives the diabetogenic IGF-1 effects. This makes Fragment 176-191 a selective fat-burning peptide without GH's anabolic or glucose-altering effects. Related to AOD-9604 (which adds a tyrosine for stability), it remains a popular research peptide for body composition.

Research Use Cases

  • Selective lipolysis without blood glucose effects
  • Body recomposition: fat reduction preserving muscle
  • Obese or insulin-resistant individuals seeking GH-like fat loss

Dosing Protocol

Typical Dose250-500 mcg/day
Frequency1-2× daily (fasted)
Half-Life~30 minutes
Common Vial Sizes2 mg, 5 mg

Dosing Protocols

Standard Fat Loss

Dose
250 - 500 mcg
Frequency
1-2x daily (SC) — fasted
Note: Must inject in a fasted state (1+ hours after food, wait 30 min before eating). AM and pre-cardio are optimal windows.

Advanced Protocol

Dose
500 mcg
Frequency
Twice daily — AM and pre-cardio (SC fasted)
Note: Combines well with AOD-9604 or GHK-Cu. Do not exceed 1 mg/day.

Body-Weight Dosing Reference

Estimated doses extrapolated from the published research range of 250500 mcg/day (referenced to 70 kg / 154 lb). These are approximations — consult a qualified healthcare provider for personalised guidance.

WeightLowTargetHigh
120 lb(54 kg)193 mcg289 mcg386 mcg
140 lb(63 kg)225 mcg338 mcg450 mcg
160 lb(73 kg)261 mcg391 mcg521 mcg
180 lb(82 kg)293 mcg439 mcg586 mcg
200 lb(91 kg)325 mcg488 mcg650 mcg
220 lb(100 kg)357 mcg536 mcg714 mcg
250 lb(113 kg)404 mcg605 mcg807 mcg

💉 For exact syringe units based on your vial concentration, use the HGH Fragment 176-191 Reconstitution Calculator →

Administration

Route
Subcutaneous injection
Timing
Fasted state — morning or pre-cardio. Wait 30 min before eating after injection.
Fasting Required?
Yes — inject on an empty stomach

Expected Timeline

Week 1-2
Increased lipolysis in fasted state. Fat stores mobilized preferentially in visceral and stubborn areas.
Month 1-3
Sustained fat loss particularly in stubborn areas when combined with caloric deficit and exercise.

Who Is It For?

Fat Loss

High

Specifically targets fat metabolism without the side effects of full HGH. Best for stubborn and visceral fat reduction.

Metabolic Health

Moderate

Does not affect blood glucose or IGF-1 levels — suitable for those who cannot use full GH.

Reconstitution Example

Vial
5 mg
Water
2 mL
Concentration
2.5 mg/mL
Per Unit (100u syringe)
25 mcg
Dose of 250 mcg = 10 units on a 100-unit insulin syringe

Safety & Considerations

Research peptide. Does not induce insulin resistance or affect IGF-1. No significant systemic side effects reported. Must be administered in a fasted state for optimal lipolytic effect.

Regulatory & Legal Status

FDA Status (US)
Research Only
WADA Status (2026)
Not Listed

Not currently on the WADA 2026 Prohibited List. Policies may change — verify before competition.

Classification

Research Chemical

US Compounding: Not eligible / not available

⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.

Interactions & Contraindications

Does not elevate IGF-1 or affect glucose — advantageous in metabolic patients. Minimal documented drug interactions. Lower potency for fat loss than full GH — dose accordingly.

Synergies & Common Stacks

+ CJC-1295 no DAC

Fragment handles fat burning; CJC-1295 drives GH's anabolic and recovery benefits. Splits GH's two main effects for targeted outcomes.

Same rationale — Ipamorelin provides clean GH elevation for recovery; Fragment 176-191 handles the fat loss component without glycemic impact.

Dosing Quick Reference

HGH Fragment 176-191— Dosing Guide
Dose Range
250-500 mcg/day
Half-Life
~30 minutes
Frequency
1-2× daily (fasted)
Route
Subcutaneous
2 mg vial5 mg vial
💧 2 mL BAC water📐 2.5 mg/mL concentration💉 25 mcg/unit (100u syringe)
Fat Losscalcmypeptide.com

Frequently Asked Questions

Is HGH Fragment 176-191 the same as AOD-9604?
Very similar — both target the same fat-burning region of HGH. AOD-9604 has an additional tyrosine residue at the N-terminus and has FDA GRAS status. Fragment 176-191 is the original truncated peptide from hGH research.
Must I inject Frag 176-191 fasted?
Yes — inject on an empty stomach with no food for 1+ hours before and 30 minutes after. Insulin from food intake directly blunts the lipolytic effect by inhibiting hormone-sensitive lipase.

References

  1. Heffernan M et al. "The lipolytic effect of a human growth hormone fragment".” J Endocrinol (2001). PMID: 11182753

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