PeptideWADA ProhibitedCompare

HGH Fragment 176-191

Also known as: HGH Frag, Fragment 176-191, Frag

1 · Natty510 · Enhanced

Lower numbers = closer to natural. Higher numbers = more enhanced.

Why this rating?

HGH Fragment 176-191 is the isolated C-terminal portion (amino acids 176-191) of the GH molecule that specifically stimulates lipolysis without affecting IGF-1, insulin, or blood glucose. It provides only the fat-burning portion of GH effects without systemic hormonal changes. The mechanism is real (beta-3 adrenergic-driven lipolysis) but human evidence for meaningful fat loss is weak-to-unproven even for its better-studied analog AOD-9604, whose pivotal 24-week Phase IIb trial failed to beat placebo, and no dedicated human trials exist for the unmodified fragment itself. Rated 2: a genuine but minor, narrowly-targeted fat-metabolism effect beyond natural baseline, with no anabolic/muscle-building action, matching the recalibrated rating given to its close relative AOD-9604.

Overview

A fragment of the GH molecule (amino acids 176-191) that targets fat loss without affecting insulin or blood glucose. Provides the lipolytic benefits of GH without the typical GH side effects.

Important Warnings

•Human evidence for meaningful fat loss is weak. AOD-9604 Phase II trials were modest and it failed to gain approval as an obesity drug
•Research chemical status means purity and dosing accuracy vary between sources
•WADA prohibited (listed under S2 as AOD-9604/GH fragment). Will cause a positive drug test

Purpose & Use Cases

Targeted Fat Loss

Directly promotes lipolysis without systemic GH effects.

No Insulin Impact

Does not affect blood glucose or insulin sensitivity.

Benefits

Direct fat burning effect
No blood glucose impact
No insulin resistance
Does not increase IGF-1 (no organ growth)
Minimal side effects
Can be used long-term

Good to Know

The lipolysis-only piece of GH

The 176-191 sequence is the C-terminal fragment of growth hormone that carries GH's fat-burning action (via the beta-3 adrenergic pathway and hormone-sensitive lipase) but does NOT bind the GH receptor. So it burns fat without raising IGF-1, without insulin resistance, without glucose changes and without organ growth. The trade-off is that it is much weaker than real GH.

Not a growth hormone or a secretagogue

It neither replaces GH nor stimulates the pituitary to release it. IGF-1 and GH levels are unchanged. This is purely a fat-loss peptide, which is why it carries none of the classic GH side effects (water retention, carpal tunnel, glucose issues).

AOD-9604 is a related but distinct analog

AOD-9604 is a modified version (an added N-terminal tyrosine) developed by Metabolic Pharmaceuticals; it is often used interchangeably with Frag 176-191 but is technically a separate molecule. Both share the same GH-receptor-independent, IGF-1-neutral profile.

Human evidence is weak. Be honest

Despite the clean mechanism, human results are underwhelming, and that evidence is for AOD-9604, not the unmodified fragment. AOD-9604's Phase II obesity trials tested oral doses from 0.25mg up to 30mg/day; the 1mg dose showed modest fat loss over 12 weeks (~2.6kg vs 0.8kg placebo), but the larger, pivotal 24-week Phase IIb trial (~500+ subjects) failed to beat placebo, and development was discontinued in 2007. Physique use of Frag 176-191 itself is almost entirely community practice extrapolated from that data, not proven outcomes for this specific peptide.

Fasted, pre-cardio timing

Insulin blunts lipolysis, so it is injected fasted, often before fasted cardio, for the best fat-mobilising effect. Because it does not touch glucose or hormones, it can be run longer than most GH-based options.

Dosage Guidelines

Experience Level	Dosage Range
Beginner	250 – 250 mcg/day
Intermediate	250 – 500 mcg/day
Advanced	500 – 500 mcg/day

Frequency

1-2x daily subcutaneous injection, fasted (commonly split morning + before bed given the ~30-minute half-life)

Typical Cycle Length

4 – 12 weeks

Notes

Best injected fasted, ideally 30-60 min before fasted cardio for maximum lipolysis. No formal human trials exist for the unmodified fragment itself. The 250-500mcg/day protocol is community-derived by analogy with its more stable analog AOD-9604 (which was clinically dosed at 0.25-30mg/day orally), not from peer-reviewed dosing studies on Frag 176-191 specifically.

Side Effects

Injection Site Irritation

uncommon

Severity

1/5

Minor redness or irritation at injection site.

Mitigation

Rotate injection sites.

Headache

common

Severity

1/5

Mild-to-moderate headache, particularly in the first few days of use, reported in community use, and the most frequently reported adverse event in AOD-9604 clinical trials (nervous-system disorders, mainly headache, in ~26-30% of subjects across the pivotal 12- and 24-week oral trials, even at the lower 0.25-1mg/day doses closest to typical AOD-9604/frag use).

Mitigation

Usually transient; ensure adequate hydration.

Lethargy

rare

Severity

1/5

Occasional tiredness.

Mitigation

Usually mild and transient.

General Mitigation Strategies

Rotate injection sites. Very well-tolerated peptide with minimal side effects (occasional injection-site irritation, mild headache, or fatigue, especially early on). No impact on blood glucose makes it suitable for many users.

Post Cycle Therapy (PCT)

✓PCT Not Required

Does not affect hormones. No PCT required.

How It Works

HGH Fragment 176-191 is a synthetic replica of amino acids 176-191 (the C-terminal lipolytic domain) of the human growth hormone molecule. It specifically stimulates lipolysis (fat burning) via the beta-3 adrenergic receptor pathway and inhibits lipogenesis (fat storage) without binding the GH receptor, and without affecting insulin sensitivity or IGF-1 levels.