Description
What Is HGH Fragment 176-191?
HGH Fragment 176-191 is a synthetic peptide consisting of the C-terminal 16 amino acids of human growth hormone (positions 176–191). It was originally isolated by researchers investigating which region of the GH molecule was responsible for its fat-loss effects. The answer was this specific tail-end fragment — it retains the lipolytic (fat-burning) activity of full GH while completely lacking the growth-promoting, IGF-1-elevating, and glucose-disrupting effects.
HGH Fragment 176-191 works through a GH-receptor-independent pathway. It stimulates lipolysis (the breakdown of stored fat into free fatty acids) and inhibits lipogenesis (the formation of new fat). Because it does not bind the GH receptor, it does not raise IGF-1, does not affect blood glucose or insulin sensitivity, does not cause water retention, and does not promote cellular proliferation. It is purely fat-specific. This fragment is also the parent compound of AOD-9604, which is an acetylated, more metabolically stable version with a tyrosine residue added at the C-terminus.
Use our Peptide Dosage to calculate your exact dose based on vial size and concentration.
Key Characteristics:
- C-terminal GH fragment — 16 amino acids from positions 176–191 of the human growth hormone molecule
- Purely fat-specific — stimulates lipolysis (fat breakdown) and inhibits lipogenesis (fat storage) without any growth, muscle-building, or metabolic side effects
- GH-receptor-independent — does NOT bind the GH receptor, does NOT raise IGF-1, does NOT affect blood glucose or insulin
- Very short half-life — approximately 15–20 minutes, making split dosing critical for sustained lipolytic activity
- Fasting is non-negotiable — insulin directly inhibits lipolysis; the fragment must be injected in a fully fasted state to be effective
- Parent compound of AOD-9604 — AOD-9604 is the acetylated, stabilized version with a tyrosine addition; both target the same fat-loss pathway
For a complete overview of its mechanism and research, see our full HGH Fragment 176-191 profile. New to peptides? Start with the Beginner’s Guide to Peptides.
How HGH Fragment 176-191 Dosage Is Determined
HGH Fragment 176-191 dosing — expressed in micrograms (mcg) per injection or per day — is derived from animal studies on the lipolytic region of GH, allometric scaling from rodent models, and extensive community experience. No human clinical trials have established an official dosing regimen for the unmodified fragment. The commonly used 250–500 mcg range is based on translated research data and years of anecdotal reporting.
Animal Studies
The foundational research by Ng and colleagues identified amino acids 176–191 as the region of GH responsible for lipolytic activity. Animal studies demonstrated that this fragment stimulates lipolysis in adipose tissue and inhibits lipogenesis without producing the growth-promoting or diabetogenic effects of full GH. Rodent studies typically used doses in the range of 250–500 mcg/kg, with consistent fat loss observed without changes in IGF-1 levels or glucose tolerance.
The AOD-9604 Clinical Bridge
While the unmodified fragment lacks human trials, its acetylated derivative AOD-9604 has been studied in human clinical trials. Phase II trials used oral doses of 1–50 mg daily and demonstrated fat loss without changes in IGF-1, glucose, or insulin. Community dosing for the injectable unmodified fragment is loosely informed by the AOD-9604 data, adjusted for the higher bioavailability of subcutaneous injection versus oral administration.
Community & Practitioner Experience
The 250 mcg twice-daily fasted protocol has emerged as the community standard over the past decade. This protocol balances the fragment’s very short half-life (~15–20 minutes) with practical fasting requirements. Advanced users may increase to 500 mcg per injection, though diminishing returns are commonly reported above this threshold.
Standard HGH Fragment 176-191 Dosage Ranges
HGH Fragment 176-191 is administered exclusively by subcutaneous injection in a fasted state. Oral dosing is not viable for the unmodified fragment (unlike AOD-9604, which has been studied orally). The tables below summarize the most commonly used protocols.
Dosage by Experience Level
| Level | Dose | Frequency | Notes |
|---|---|---|---|
| Beginner | 250 mcg | Once daily AM fasted | Assess tolerance for 1–2 weeks before progressing to twice daily |
| Intermediate | 250 mcg | Twice daily (AM + PM fasted) | Most effective standard protocol; AM upon waking, PM 3+ hours after last meal |
| Advanced | 500 mcg | Twice daily (AM + PM fasted) | Diminishing returns above 500 mcg per injection; reserve for aggressive cutting |
Dosing Timing
| Injection | Timing | Fasting Requirement | Post-Injection Fast |
|---|---|---|---|
| AM dose | Immediately upon waking | Overnight fast (8+ hours) | Wait 30–60 min before eating |
| PM dose | Before bed | 3+ hours after last meal | No food after injection (sleep) |
