HGH Fragment 176-191
Also known as: HGH Frag, Fragment 176-191, AOD-9604 Precursor
Growth Hormone Fragment | Fat Loss Peptide
Overview
HGH Fragment 176-191 is the fat-burning segment of human growth hormone, corresponding to amino acids 176 through 191 of the full GH molecule. It stimulates lipolysis and inhibits lipogenesis without the growth-promoting or insulin-disrupting effects associated with full-length HGH. AOD-9604 is a modified version of this fragment with an added N-terminal tyrosine residue.
Key benefits
- Stimulates lipolysis without growth hormone side effects
- Does not affect blood glucose or insulin sensitivity
- Does not increase IGF-1 levels
- Selectively targets fat metabolism
- No impact on bone or organ growth
Mechanism of action
Mimics the lipolytic region of human growth hormone by stimulating fat breakdown through beta-3 adrenergic receptor pathways. Unlike full HGH, it does not bind the growth hormone receptor, so it does not increase IGF-1 levels or interfere with glucose metabolism. The fragment selectively targets adipose tissue to promote fat oxidation.
Molecular data
- Type
- hGH C-terminal fragment (176-191)
- Half-life
- 15-20 minutes
Sequence
Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe
Indications
What the research community uses this compound for, with self-reported effectiveness.
Fat Loss
Lipolysis Enhancement
Most effectiveIncreases fat oxidation and breakdown of stored triglycerides in adipose tissue without affecting glucose homeostasis.
Lipogenesis Inhibition
EffectiveReduces new fat synthesis and storage, complementing the lipolytic action for overall fat reduction.
Body Composition
EffectivePromotes selective fat loss while preserving lean mass, particularly effective when combined with a caloric deficit and exercise.
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Injectable
Subcutaneous injection is the standard route. Best administered twice daily on an empty stomach -- once in the morning and once before bed. Avoid eating for at least 30 minutes after injection for optimal fat-burning effect.
| Protocol | Dose | Frequency | Route / duration |
|---|---|---|---|
| Fat loss - Standard | 250mcg | Twice daily (morning fasted + pre-bed) | SubQ |
| Enhanced fat loss | 500mcg | Twice daily (morning fasted + pre-bed) | SubQ |
| Conservative start | 250mcg | Once daily (morning, fasted) | SubQ |
Preparation
You will need
- Lyophilized HGH Frag 176-191 vial
- Bacteriostatic water (BAC water)
- Insulin syringes (0.5-1mL)
- Alcohol swabs
- Sterile work surface
Steps
- Allow vial to reach room temperature (15-20 minutes)
- Calculate required bacteriostatic water volume
- Clean vial stopper with alcohol swab
- Draw BAC water into syringe
- Inject slowly down vial side (not directly onto powder)
- Gently swirl until dissolved (never shake vigorously)
- Store reconstituted solution at 2-8 degrees C
- Use within 28 days
Work out the water volume and syringe units in the reconstitution calculator →
Interactions
Pairwise interactions with other compounds you might be cycling — the same data behind the cycle builder's safety check.
AOD-9604
AvoidSame mechanism of action. AOD-9604 is a modified version of this fragment; using both is redundant and unnecessary.
HGH
MonitorRedundant lipolytic mechanism. Full HGH already contains the 176-191 sequence, so combining provides diminishing returns for fat loss while adding HGH-related side effects.
Clenbuterol
SynergisticBoth target fat loss through complementary adrenergic pathways. The combination may enhance lipolysis beyond either compound alone.
Timeline
Typical week-by-week effects reported in clinical and observational data.
- Week 1-2
Minimal noticeable changes; fragment accumulating and establishing lipolytic signaling
- Week 3-4
Subtle improvements in fat loss, especially around the midsection with proper diet
- Week 5-8
More noticeable fat reduction and improved body composition with consistent use
- Week 8-12
Continued fat loss and body recomposition; most users run 8-12 week cycles
Safety
Reported adverse effects, contraindications, and what to monitor on cycle.
Common side effects
- Injection site irritation (redness, mild swelling)
- Headache, particularly in the first few days
- Generally well-tolerated with a favorable safety profile
Stop signs — stop and seek advice
- Severe injection site reactions or signs of infection
- Hypoglycemia symptoms if combined with insulin (dizziness, sweating, confusion)
- Allergic reactions (rare)
- Any persistent or concerning symptoms
Contraindications
- Pregnancy or breastfeeding
- Active cancer or history of malignancy
- WADA prohibited - athletes subject to testing must avoid
Monitoring
- Injection site reactions
- Blood glucose if combining with insulin or diabetes medications
- Body composition changes
Quality checks
What a legitimate product looks like, what should give pause, and what should make you stop.
Good signs
- White lyophilized powder with uniform appearance
- Crystal clear solution without particles after reconstitution
- Certificate of Analysis showing >98% purity by HPLC
- Proper cold-chain shipping
Warning signs
- Not FDA approved - research chemical only
- WADA prohibited substance
Stop signs — don't use
- Discolored or clumped powder (yellow indicates degradation)
- Cloudy solution after reconstitution
- Collapsed or moisture-damaged appearance
Recent research
Newer papers and trial readouts on file for this compound, with source and date.
2014 · Drug Testing and Analysis
Detection and in vitro metabolism of AOD9604
Developed detection methods for AOD-9604 and related hGH fragments, relevant for anti-doping analysis and understanding in vivo metabolism of the 176-191 sequence.
References
Primary literature and clinical-trial data informing this entry.
Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment
Heffernan MA, Thorburn AW, Fam B, Summers R, Conway-Campbell B, Waters MJ, Ng FM · International Journal of Obesity · 2001
Both hGH and the C-terminal fragment (176-191) reduced body weight gain, increased fat oxidation, and stimulated lipolysis in obese ob/ob mice without affecting glucose metabolism.
The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice
Heffernan MA, Jiang WJ, Thorburn AW, Ng FM · Endocrinology · 2001
The hGH fragment and its modified form AOD-9604 both increased beta-3 adrenergic receptor expression in obese mice. Effects were abolished in beta-3-AR knockout mice, confirming this receptor pathway is essential for the lipolytic action.
Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone
Ng FM, Jiang WJ, Gianello R, Pitt C, Heffernan M · Hormone Research · 2000
Characterized the metabolic properties of the hGH 176-191 lipolytic domain, demonstrating antilipogenic activity independent of the growth hormone receptor.
Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolism
Heffernan MA, Heffernan MJ, Jiang WJ, Thorburn AW, Ng FM · American Journal of Physiology - Endocrinology and Metabolism · 2000
Oral treatment with the synthetic hGH fragment for 30 days significantly reduced body weight gain and altered lipogenic and lipolytic activity in adipose tissue of obese mice.
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