Fat Loss

HGH Fragment 176-191

AOD-9401 · Fragment 176-191 · Frag

Unmodified hGH C-terminal 176–191 fragment. AOD-9604 adds tyrosine. Neither is somatropin. Neither is an Egrifta VAT indication. Lipolytic-region hypothesis, not a labeled fat-loss drug.

Not FDA-approved - research chemical

Reviewed by CalcMyPeptide Editorial Team

·Last updated: August 2026·Evidence: Low·2 peer-reviewed citations

Typical research dose

250-500 mcg/day

Frequency

1-2× daily (fasted)

Half-life

~30 minutes

Common vials

2 mg / 5 mg

CAS

66004-57-7

Molecular weight

1817.1 g/mol

Use-case scores

0–10 against the evidence we have, not a gym ranking. Hidden domains do not apply here.

Metabolic / weight3/10
Same lipolytic-region hypothesis as AOD-9604 without the tyrosine cap. No approved indication. Community ceiling.

Compound card

Class: hGH C-terminal fragment (not AOD-9604, not somatropin)
Formula: C78H125N23O23S2
Status: Not FDA-approved · research use

Dose it

5 mg + 2 mL BAC water → 2.5 mg/mL · 250 mcg ≈ 10 units (U-100)

Open in calculator

How it works

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

Phase	Dose	Frequency	Notes
Standard Fat Loss	250 - 500 mcg	1-2x daily (SC) - fasted	Must inject in a fasted state (1+ hours after food, wait 30 min before eating). AM and pre-cardio are optimal windows.
Advanced Protocol	500 mcg	Twice daily - AM and pre-cardio (SC fasted)	Combines well with AOD-9604 or GHK-Cu. Do not exceed 1 mg/day.

Administration

Route / form

Subcutaneous injection

Timing

Fasted state - morning or pre-cardio. Wait 30 min before eating after injection.

Empty stomach?

Yes - Empty stomach (typical for this injectable class).

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 it is 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

Vial	Water	Concentration	Example dose
5 mg lyophilized	2 mL BAC	2.5 mg/mL	250 mcg on 5 mg / 2 mL (2.5 mg/mL) = 0.10 mL = 10 units on a U-100.

Change vial size or water volume? Open the reconstitution calculator.

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.

Limits of current evidence

Do not launder Egrifta VAT percentages onto this fragment.
Fasted community dosing is folklore, not a PK label.

Verdict

Fragment 176–191 is the unmodified C-terminal GH snippet. AOD-9604 adds tyrosine. Neither is somatropin. Neither is a visceral-fat NDA.

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.

+ Ipamorelin →

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

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

Heffernan M et al. “"The lipolytic effect of a human growth hormone fragment".” J Endocrinol (2001). PMID: 11182753
Ng FM, et al. “Fat metabolism and growth hormone: investigation with GH fragment 176-191.” Obes Rev (2000). PMID: 12119988

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