HGH Fragment 176-191
Fat Loss / Metabolic PeptideresearchAlso known as: HGH Frag, Fragment 176-191, GH Frag, Tyr-hGH177-191
A modified fragment of human growth hormone (amino acids 176-191) that specifically promotes fat metabolism and lipolysis without the growth-promoting or diabetogenic effects of full HGH.
Overview
HGH Fragment 176-191 is a synthetic peptide consisting of the C-terminal portion of human growth hormone, spanning amino acids 176-191, with a tyrosine modification at position 177. This specific region of HGH was identified as the portion responsible for the hormone's fat-burning properties. Researchers at Monash University in Australia demonstrated that this fragment retains the lipolytic (fat-burning) activity of growth hormone while lacking its growth-promoting, insulin-resistant, and IGF-1-raising effects. The fragment works by mimicking the way natural growth hormone regulates fat metabolism — stimulating lipolysis and inhibiting lipogenesis. It is closely related to AOD 9604, which is a further-modified version of the same fragment. HGH Fragment 176-191 has been popular in the bodybuilding and biohacking communities for targeted fat loss without the side effects associated with full growth hormone administration.
Mechanism of Action
HGH Fragment 176-191 acts on fat metabolism: (1) Stimulates lipolysis (fat breakdown) by activating beta-3 adrenergic receptor-mediated pathways in adipose tissue; (2) Inhibits lipogenesis (new fat formation) by blocking fatty acid synthase activity; (3) Promotes release of stored fatty acids from adipocytes for oxidation; (4) Does not bind to the full growth hormone receptor, avoiding IGF-1 stimulation; (5) Does not affect glucose metabolism or insulin sensitivity (no diabetogenic effect); (6) Preferentially targets visceral and abdominal fat deposits; (7) May enhance cartilage regeneration independent of IGF-1.
Molecular Formula
C78H123N21O20S2
Molecular Weight
1815.10 g/mol
Sequence
Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe
Dosage Protocols
Dose Range
250mcg – 500mcg
Frequency
Once to twice daily
Route
subcutaneous
Cycle Length
8-12 weeks
Best administered on an empty stomach, typically morning and/or pre-bed. Avoid eating for 30 minutes post-injection to maximize efficacy. Inject into abdominal subcutaneous fat. Can be combined with exercise for enhanced results.
Source: Community protocols and preclinical research
🧮 Personalized Dosage Calculator
💰 Estimated Pricing
Typical Supply
5mg vial
Last Updated
2026-02
Fat-burning HGH fragment. Research: $25-50/vial. Often used with AOD-9604 (same mechanism). No GH-like side effects.
⚠️ Prices are estimates based on publicly available data and may vary significantly by vendor, location, and prescription status. This is not medical or financial advice.
Side Effects
| Effect | Severity |
|---|---|
| Injection site irritation | mild |
| Drowsiness | mild |
| Headache | mild |
| Hypoglycemia symptoms | mild |
Pros & Cons
Targets fat loss specifically without the growth-promoting or diabetogenic effects of full HGH
Does not raise IGF-1 levels, reducing theoretical cancer risk associated with growth hormone
No negative impact on glucose metabolism or insulin sensitivity
Preferentially targets visceral/abdominal fat, the most metabolically dangerous fat depot
Limited clinical evidence — most data from animal studies and community reports
Requires fasted administration for optimal effect, limiting convenience
Effects are modest without concurrent diet and exercise — not a magic bullet
Very similar to AOD 9604, which has more research — may not offer distinct advantages
Research Studies
🩸 Blood Work
No specific bloodwork requirements reported for this peptide. General health panels are always recommended before starting any peptide protocol.
Legal Status
Not FDA-approved. Available as a research chemical. Banned by WADA. Subject to regulatory scrutiny in some jurisdictions. AOD 9604 (related) has more regulatory history.
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