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Animal data onlyNot FDA approved

HGH Fragment 176-191

Also known as: HGH Frag 176-191 · HGH Frag · hGH 176-191 · Fragment 176-191 · Frag 176-191 · Frag 176 · GH fragment 176-191

Updated 33 sources

A 16-amino-acid piece from the tail end of human growth hormone, sold as a research peptide for fat loss. It releases no growth hormone. No human trial has tested it; the data are rodent and cell studies, and most of those used the related AOD-9604. Even the sequence in the vial varies by seller.
Calculate with HGH Fragment 176-191Dosage chart

Quick facts

Half-life
  • About 30 minutes, per guides; no measured value for the fragment.
  • 15 to 20 minutes, per another guide; also unsourced.
  • For the related AOD-9604: about 3 minutes after an IV dose in pigs, and 4 minutes in rat blood in a test tube.
Routes
  • Subcutaneous injection
Forms
  • Vial (powder)
Reported dose ranges
  • 250 to 1,000 mcg (subcutaneous injection)
Vial sizes
  • 2 mg, 5 mg, 10 mg
Chemistry
  • 1,799.1 g/mol · C78H123N23O22S2
FDA status
  • Not FDA approved
WADA
  • Prohibited

What people use HGH Fragment 176-191 for

  • Fat loss, mostly belly, lower back and love-handle fat, injected fasted
  • An add-on to retatrutide or tirzepatide during a cut
  • Recomposition alongside CJC-1295 and ipamorelin
  • A fat-loss option that is said not to raise IGF-1, unlike full HGH

How it is thought to work. Rodent work on the 177-191 tail of growth hormone found it blocked fat synthesis and reduced fat gain in obese mice; the tyrosine analog AOD-9604 raised fat oxidation without binding the GH receptor. Native hGH 176-191 starts with phenylalanine. Some vials sold as Frag carry a tyrosine-first sequence, the same as AOD-9604. A 1978 rat study saw a short blood sugar rise with 176-191.

HGH Fragment 176-191 dosing

7 protocols from studies, guides and community reports, grouped by goal. Tap a source badge to see where a number came from.

Fat loss2

Fat loss, common community range

Amount
250 to 500 mcg
How often
250 to 500 mcg a day, as one or two fasted injections
Route
SubQ, vial (powder)
Cycle
8 to 12 weeks
Timing and details

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Fat loss, guide protocol with breaks

Amount
250 to 500 mcg
How often
250 to 500 mcg per injection, once or twice daily
Route
SubQ, vial (powder)
Cycle
4 to 8 weeks on
Rest
2 to 4 weeks off
Timing and details

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Other protocols: injected5

Beginner start

Amount
250 mcg
How often
Once daily, morning fasted
Route
SubQ, vial (powder)
Cycle
6 to 8 weeks
Timing and details

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Split dose, morning and bedtime

Amount
250 mcg
How often
Twice daily: on waking fasted and before bed
Route
SubQ, vial (powder)
Cycle
8 to 12 weeks
Timing and details

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Advanced, higher split dose

Amount
500 mcg
How often
Twice daily: morning fasted and before bed
Route
SubQ, vial (powder)
Cycle
12 to 16 weeks
Rest
4 weeks off
Timing and details

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Higher single morning dose

Amount
500 to 1,000 mcg
How often
Once daily, morning fasted
Route
SubQ, vial (powder)
Cycle
4 to 8 weeks
Timing and details

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Before fasted cardio or training

Amount
250 to 500 mcg
How often
5 days a week: 250 mcg before fasted morning cardio plus 250 mcg before training, or 500 mcg before training
Route
SubQ, vial (powder)
Timing and details

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Doses shown are what sources report, labelled by origin. Not medical advice.

Full HGH Fragment 176-191 dosage guideEvery titration step in syringe units, missed doses and how to mix.

Vial strengths and syringe units

Every HGH Fragment 176-191 vial size with the water volumes sources use. Units are what to draw on a U-100 insulin syringe, worked out exactly.
HGH Fragment 176-191: concentration and U-100 syringe units for each vial size and water volume
WaterStrength250 mcgdose, units500 mcgdose, units1,000 mcgdose, units
2 mg vial
0.8 mLCompetitor guide2.5 mg/mL100.1 mL200.2 mL400.4 mL
1 mLCompetitor guide2 mg/mL12.50.125 mL250.25 mL500.5 mL
2 mLCompetitor guide1 mg/mL250.25 mL500.5 mL1001 mL
5 mg vial
2 mLCompetitor guide2.5 mg/mL100.1 mL200.2 mL400.4 mL
2.5 mLCompetitor guide2 mg/mL12.50.125 mL250.25 mL500.5 mL
10 mg vial
2 mLCompetitor guide5 mg/mL50.05 mL100.1 mL200.2 mL
Units are on a U-100 insulin syringe (100 units = 1 mL). U-50 and U-30 barrels read the same units.Water volumes from

Doses shown are what sources report, labelled by origin. Not medical advice.

Calculate with this peptideYour vial, your water, your dose: HGH Fragment 176-191 in syringe units, with the math shown.

HGH Fragment 176-191 side effects

What trials and labels report, kept apart from what users and guides report. Frequencies are worded as each source states them.

Reported by users and guides6

From community reports and dosing guides. Not measured rates.

  • Injection-site redness, burning or itching

    Listed as common by one guide; no trial data

    How people manage it

    • Rotate injection sites (abdomen, outer thigh, upper arm).

  • Lumps and itching at injection sites

    Single Reddit report at 1.5 mg daily; cleared in 5 to 7 days after stopping

    How people manage it

    • The user stopped the fragment and kept the other compounds to find the cause.

  • Mild headache

    Commonly listed for the first days or week

  • Lightheadedness with long fasts or fasted cardio

    Described as affecting a predictable minority

    How people manage it

    • Add one variable at a time instead of stacking a long fast, fasted cardio and the peptide on the same morning.

  • Mild fatigue

    Listed for the first few days

  • Increased hunger

    Listed as less common

All 7 HGH Fragment 176-191 side effects and how people manage themEvery management tip, who should not use it, and side-effect questions.

Who should avoid it

  • Pregnancy or breastfeedingCondition

    Guides list it as a reason to skip; there are no human safety data.

  • Active cancerCondition

    Guides list it as a reason to skip.

  • Type 1 diabetesCondition

    The fasted-dosing routine conflicts with insulin management, per the guides.

  • Eating disorder historyCondition

    The routine leans on fasting and restriction; guides say to skip it.

  • Somatropin (HGH)Substance

    Called redundant: full HGH already contains the 176-191 sequence, so adding the fragment brings little extra fat loss.

Storage

Powder (before mixing)

Temperature
2 to 8 °C

Fridge at 2 to 8 C, or frozen.

Powder (before mixing)

Temperature
-20 °C

Freezer at -20 C in the dark; the vendor gives 3 years.

Mixed vial

Temperature
2 to 8 °C
Use within
14 to 21 days

Fridge at 2 to 8 C, use within 14 to 21 days, do not freeze, keep from light.

Mixed vial

Temperature
2 to 8 °C
Use within
28 days

Fridge at 2 to 8 C for 28 days, per another guide.

Mixed with: Bacteriostatic water; some users add a little acetic acid first

Mixing. Gelling and cloudiness are common complaints, including 5 mg vials that turned to gel after 1 mL of BAC water. The usual community fix is a small amount of acetic acid first, then BAC water; reported strengths vary widely (0.6% in one post, 30% in another). Pick one water volume and keep it the same for every vial.

Stacks people report

Combinations from guides and community posts, with the reason given.
  • AOD-9604

    Some users run both, 500 mcg each on waking before fasted cardio. One guide calls the pair aggressive and largely redundant, and suggests Frag 250 mcg in the morning with AOD-9604 300 mcg in the evening, or alternating days.

  • Ipamorelin

    Fragment for fat, ipamorelin for GH-driven recovery and sleep: Frag 250 mcg morning and before bed with ipamorelin 200 to 300 mcg at the same times, 8 to 12 weeks.

  • CJC-1295

    CJC-1295 (no DAC) with ipamorelin on training days and Frag 250 to 500 mcg twice daily on rest days, per one guide. Premixed Frag, CJC-1295 and ipamorelin blends (6 + 3 + 3 mg) are also sold.

  • Retatrutide

    The commonest Reddit pattern: weekly retatrutide or tirzepatide for appetite plus daily fasted Frag. Users note the GLP-1 does most of the fat loss.

Related versions

  • AOD-9604

    AOD-9604 is the tyrosine-capped, ring-closed version (hGH 177-191 plus an N-terminal tyrosine) with a human safety program; the native 176-191 fragment starts with phenylalanine and has none.

Compare HGH Fragment 176-191

Evidence and legal status

Evidence: animal data only

No human trial has tested the fragment. The evidence is rodent and cell work from the 1970s to 2000s, much of it on hGH 177-191 or the tyrosine analog AOD-9604: less fat gain in obese mice, more fat oxidation, no GH-receptor binding. A 1978 rat study found hGH 176-191 caused a short rise in blood glucose and insulin.

FDA and WADA

Not FDA approved

No approval, no trial program and not on FDA's compounding lists.

Not FDA approved. Not named on FDA's 503A bulk-substance nomination list or its compounding safety-risk page; FDA's 2024 review covered AOD-9604 only. No FDA warning letter naming it was found.

WADA bans it at all times: S2.2.3 of the 2026 Prohibited List names growth hormone fragments, e.g. AOD-9604 and hGH 176-191.

WADA: Prohibited

HGH Fragment 176-191 questions

What is HGH Fragment 176-191?

A 16-amino-acid piece from the tail end of human growth hormone, sold as a research peptide for fat loss. It does not release growth hormone and has no approved use.

What is the usual HGH Frag 176-191 dose?

Community practice is 250 to 500 mcg a day, injected under the skin fasted, as one or two doses, for 8 to 12 weeks. No human trial set this dose.

How many units is 250 mcg of HGH Frag?

It depends on the water. A 5 mg vial with 2 mL of bacteriostatic water puts 250 mcg at 10 units on a U-100 insulin syringe. A 2 mg vial with 2 mL puts it at 25 units. Use the calculator for your own vial.

Should I inject Frag 176-191 in the morning or at night?

Most protocols use a morning dose on an empty stomach, and some add a second dose before bed at least 3 hours after eating. The reasoning is that insulin blunts fat breakdown; no study has compared timings.

Does HGH Fragment 176-191 work?

There is no human trial, so nobody knows. In rodents, related fragments cut fat gain. On Reddit, results split: some report okay fat loss, while others ran it for 6 to 8 weeks fasted and saw no change.

What is the difference between HGH Frag 176-191 and AOD-9604?

AOD-9604 is growth hormone residues 177 to 191 with an added tyrosine at the front and a ring closure, and it went through human trials. Native 176-191 starts with phenylalanine. Some Frag vials list the tyrosine-first AOD sequence, so check the sequence on the label or certificate.

Does HGH Frag raise IGF-1?

Guides say no, because the fragment does not activate the growth hormone receptor. That comes from rodent and cell work on AOD-9604; no human study has measured IGF-1 on the fragment.

Does HGH Fragment 176-191 affect blood sugar?

Guides say it does not. The data are thinner than that: a 1978 rat study found hGH 176-191 caused a short-lived rise in blood glucose and a longer rise in insulin, while the AOD-9604 analog showed no hyperglycaemia in mice. No human data exist.

Why did my Frag 176-191 vial turn cloudy or gel?

It is a common complaint with this fragment and AOD-9604, often after only 1 mL of water in a 5 mg vial. The usual community fix is a little acetic acid first, then bacteriostatic water. A solution that stays cloudy or changes colour should be thrown out.

How long does reconstituted HGH Frag last?

Guides say refrigerate at 2 to 8 C and use it within 14 to 21 days; one says 28 days. Do not freeze it once mixed.

What is the half-life of HGH Fragment 176-191?

It has never been measured. Guides quote 15 to 30 minutes without a source. The related AOD-9604 broke down in about 4 minutes in rat blood.

Is HGH Fragment 176-191 FDA approved?

No. It is not on FDA's compounding lists either, and FDA has not reviewed it the way it reviewed AOD-9604.

Is HGH Frag banned in sport?

Yes. WADA's 2026 list bans growth hormone fragments at all times and names hGH 176-191.

Can I take HGH Frag with HGH?

One guide calls it redundant, since full growth hormone already contains the 176-191 sequence. Reddit users often say to pick one.

Can I stack Frag 176-191 with retatrutide or tirzepatide?

Many Reddit users do, with the GLP-1 weekly and the fragment daily and fasted. Guides note the GLP-1 does most of the work and suggest adding one thing at a time so you can tell what helps.

Ask about HGH Fragment 176-191

Answers come from this site's pages only, with a link to each source.

Sources

33 sources, each checked by date. Record updated Oct 24, 2026. Numbers are restated in our own words and labelled by where they came from.

Reference work2

  1. UniProt P01241, Somatotropin (Homo sapiens), sequenceUniProt · checked Oct 24, 2026
  2. PubChem CID 172966176, HGH Fragment 176-191PubChem · checked Oct 24, 2026

Vendor guide1

  1. HGH Fragment (176-191), catalog LT183171LifeTein (vendor product page) · checked Oct 24, 2026

Competitor guide6

  1. HGH Fragment 176-191 2 mg dosing calculatorpeptideprotocolwiki.com · checked Oct 24, 2026
  2. HGH Fragment 176-191 10 mg dosing calculatorpeptideprotocolwiki.com · checked Oct 24, 2026
  3. HGH Fragment 176-191 Dosing Protocols and Administrationpeptideprotocolwiki.com · checked Oct 24, 2026