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Lexicon
Weight management

HGH Fragment 176-191

The lipolytic piece of growth hormone, meant for fat loss without the growth and blood-sugar effects of GH, with a thin human data record.

3 min read 9 sources

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Vial with white powder and the black TPD label for HGH Fragment 176-191 on a white podium, next to it a chain of blue, light blue, white and yellowish spheres in a bright lab
No human trial of the fragment · not approved

Summary

At a glance

Sources checked on 26 Oct 2026

Length
16 amino acids

end piece of growth hormone, positions 176 to 191 of the mature chain9

Less weight gain
-56 %

obese rats, variant AOD9604 swallowed, 19 days3

Human trials of the fragment
0 trials

no trial on ClinicalTrials.gov, as of 26 Oct 20266

On the variant AOD9604
3 trials

as LAT8881 against nerve pain, migraine and back pain, phase 1 and 27

  • HGH Fragment 176-191 is the 16-amino-acid end piece of growth hormone. Most research used the variant AOD9604, which has a tyrosine instead of phenylalanine at the start.95
  • In obese mice and rats growth hormone and AOD9604 reduced weight gain. Fat breakdown and fat burning rose, also in human fat tissue in the lab.234
  • Unlike growth hormone, AOD9604 did not bind to the GH receptor, did not stimulate cell growth and left blood sugar and insulin unchanged.2
  • In mice without the beta-3 receptor the effect was absent with long-term dosing, but fat burning still rose briefly there. So the effect does not run directly through this receptor.1
  • No trial of the fragment itself is registered, AOD9604 ran as LAT8881 in small trials on pain. Everything here is preclinical research, not a recommendation.67
Profile

Updated May 2026

Class
GH fragment

lipolytic

Use
Subcutaneous

often fasted

Half-life
short
WADA
Banned

peptide hormones

Sizes
1 to 10 mg

4 sizes in the shop

Contents 16 sections
  1. At a glance
  2. What is HGH Fragment 176-191?
  3. How it works
  4. What you need
  5. Reconstitution
  6. Dosing
  7. Injection
  8. What the research shows
  9. Research status
  10. Side effects
  11. Practice
  12. Storage
  13. Related compounds
  14. FAQ
  15. Glossary
  16. Sources

What is HGH Fragment 176-191?

HGH Fragment 176-191 is a short piece from the tail end of the growth hormone molecule. This exact section carries the fat-mobilizing (lipolytic) action of GH without the other effects of the complete hormone.

The idea: use the fat-loss part of GH without the growth and blood-sugar effects of the whole hormone. Elegant on paper, but the human data record is thin.

Comparison

Growth hormone and its parts

Where each compound acts, as stated in the TPD lexicon. Tap a card to open its entry.

The whole hormone HGH 191AA (Somatropin) GH
End piece, without GH receptor HGH Fragment 176-191
Modified end piece AOD-9604 GHRH analogue, own release Tesamorelin GHRH

Simplified: the fragment and AOD9604 do not act at the GH receptor, the whole hormone does, GHRH analogues act via the body's own release.

How it works

The fragment stimulates fat burning in fat cells and inhibits the formation of new fat. Unlike complete GH it is meant to barely affect IGF-1, insulin sensitivity or blood sugar, because it lacks the parts of the molecule responsible for those.

That is the theory from the animal models. How strongly the pure fat-loss effect shows up in humans is far less established than with full GH.

Where it acts

Where AOD9604 acted in experiments

Tap a point or a card. Grey = observed. All from animal studies and lab samples.

  1. Fat tissue

    More fat breakdown, less new fat formation, also in human fat tissue in the lab4

    Observed in trials
  2. Blood sugar

    Unlike with growth hormone, no higher blood sugar and no lower insulin release (mice)2

    Observed in trials

Known targets1

Compound CHEMBL6068615 (AOD9604): two described targets, type of action on each card.

Growth hormone receptor
Gene
GHR
UniProt
P10912
ChEMBL
CHEMBL1976
Action
No binding, AOD9604 did not displace growth hormone (cell study)
Beta-3 adrenergic receptor
Gene
ADRB3
UniProt
P13945
ChEMBL
CHEMBL246
Action
More of it made, but not the direct route of the effect (mice)
Translucent fat cells as glass spheres with glowing yellow cores, with small molecules of blue and white spheres docking onto them
The fragment stimulates fat breakdown in fat cells. Symbolic image.

What you need

Supplies

4 things, numbered as in the picture

Tick off what you already have. Vial and BAC water are our real shop photos at the same size.

Vial of HGH Fragment 176-191 and bacteriostatic water at the same size with the black TPD label, next to two U-100 insulin syringes, two alcohol swabs and a sharps container with a blue lid

  1. Fragment vial

    The fragment vial (lyophilized powder, often 5mg).

    In the shop

  2. Bacteriostatic water

    Bacteriostatic water for mixing.

    In the shop

  3. U-100 insulin syringes

    U-100 insulin syringes.

    Amazon (opens a new tab)

  4. Alcohol swabs

    Alcohol swabs and a clean workspace.

    Amazon (opens a new tab)

As an Amazon associate we earn from qualifying purchases. Links open Amazon - no extra cost for you.

Reconstitution

Use the peptide calculator: pick the vial size and water amount, it shows concentration and units per shot on the U-100 syringe.

A 5mg vial with 2ml bacteriostatic water gives 2500mcg per ml. A 250mcg shot is then 10 units on the insulin syringe. Just add the water to the vial and let it dissolve.

Step by step

Dissolving the powder

Four steps, the same for every vial size.

  1. 1Wipe the cap

    Clean the rubber stopper with an alcohol swab.

  2. 2Add BAC water

    Just add it, it does not matter if it hits the powder directly.

  3. 3Swirl or shake

    Until everything has dissolved, both are fine.

  4. 4Draw up

    With the U-100 insulin syringe.

Less water higher concentration fewer units on the syringe Example: 5 mg + 2 ml = 2.5 mg/ml

Dosing

Dosing

Dosing, titration and syringe

Loading the dosing information …

  • Getting started and stepping up, drawn as a staircase
  • Units on the U-100 syringe for every step
  • How long one vial lasts

Injection

The injection is subcutaneous, into the fat layer under the skin. Common spots are the abdomen (keep about two finger-widths clear of the navel), the front and the inner side of the thigh, or the back of the upper arm.

The short version:

Injection

Where and at what angle

Pick a spot or switch the angle. Subcutaneous means: into the fat layer, not the muscle.

Rotate the spot each time, never the same one twice in a row.

90°More fat under the skin

Rule of thumb: where there is more fat under the skin, insert straight at 90 degrees. In lean people with little fat, 45 degrees, so the needle stays in the fat layer. Simplified diagram.

  1. Clean the spot with an alcohol swab and let it dry

  2. Pinch up a small fold of skin

  3. Insert the needle: at 90 degrees where there is more fat under the skin, at 45 degrees in lean people with little fat

  4. Inject slowly, wait a moment, then withdraw

  5. Put the needle straight into the sharps container

Rotate the site each time so the tissue does not get irritated. Never the same spot twice in a row.

A fasted shot before cardio is a common approach.

What the research shows

The central study (Heffernan, 2001) examined the lipolytic fragment (in the form AOD9604) in obese mice and showed that both complete GH and the fragment triggered weight loss and increased fat burning, without mediating fat loss directly through the beta3 receptor.

Important for context: this is animal research. The later modified variant AOD9604 showed only limited effects in human weight-loss studies. For the pure 176-191 fragment the human data record is correspondingly thin.

Study results

What the trials measured

Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.

Weight gain over 19 days3

Obese Zucker rats, AOD9604 swallowed daily, in grams

Weight gain3
Control 35.6 g
AOD9604 15.8 g

More than halved compared with control. The fat tissue of the treated animals broke down more fat. Unlike with growth hormone, insulin sensitivity stayed unchanged in the clamp test. Animal study, not tested in humans.

Petri dishes with yellowish pieces of fat tissue, in the centre a glass dish with one large and one smaller piece, next to a tape measure and a pipette
The data come from animal studies and fat tissue in the lab. Symbolic image.

Research status

Where the research stands

ClinicalTrials.gov lists no trial of fragment 176-191. The variant AOD9604 ran under the name LAT8881 in three small trials on nerve pain, migraine and back pain, not on weight loss. As of 26 Oct 2026. 6

  1. Preclinical Mice, rats and human fat tissue in the lab
  2. Phase 1 no registered trial
  3. Phase 2 no registered trial
  4. Phase 3 no registered trial
  5. Approval not yet
Not approved. ChEMBL lists AOD9604 under the name LAT-8881 with highest phase 2. For fragment 176-191 itself there is neither an approval nor a registered trial.6

So far there is no registered trial in humans. 6

Side effects

  • Generally well tolerated, mainly local reactions at the injection site.
  • Since little effect on blood sugar and IGF-1 is expected, the typical GH side effects are largely absent.
  • Solid long-term human data are missing. The effect itself is less established in humans than hoped.

Practice

  1. Keep expectations realistic, the pure fat-loss effect is not strongly established in humans.

  2. Dose fasted and with a gap to carbs.

  3. At best an add-on to a deficit and training, not a replacement.

  4. Banned in official competition.

A cup of black coffee, a glass of water and white running shoes on a wooden bench, next to a light blue towel

Storage

Before mixing the powder is robust, normal room temperature (around 20 to 25 degrees) is fine, ideally kept in the dark. After mixing, keep in the fridge (2 to 8 degrees), do not freeze. It stays good there for at least 4 to 6 months with barely any loss of potency, in practice considerably longer. Swirl or shake to mix, both are fine.

Shelf life

How long it keeps

Undissolved (powder) Room temperature, around 20 to 25 degrees, dark

Robust, no fridge needed.

Dissolved (mixed) Fridge, 2 to 8 degrees, do not freeze

At least 4 to 6 months with barely any loss of potency, in practice considerably longer.

  • Keep it dark
  • Dissolved: 2 to 8 degrees
  • Note the mixing date on the vial
Nine vials with white powder and blue caps in the door shelf of a bright fridge
Powder dark at room temperature, once dissolved into the fridge (2 to 8 degrees), stable there for at least 4 to 6 months. Symbolic image.

Related

Related compounds

A different path: all in the TPD lexicon.

HGH Fragment 176-191
AOD-9604 Almost the same end piece, with a tyrosine at the start HGH 191AA (Somatropin) The whole hormone the fragment comes from Tesamorelin GHRH path, approved against belly fat in HIV MOTS-c Different approach to fat metabolism 5-Amino-1MQ Different approach to fat metabolism, also preclinical

FAQ

Common questions about HGH Fragment 176-191

Short answers, each backed by the sources below.

What is HGH Fragment 176-191?

The end piece of human growth hormone, 16 amino acids from position 176 to 191 of the mature chain. This section is credited with the fat-mobilising effect of growth hormone, without its other effects.91

How does it differ from AOD9604?

AOD9604 consists of positions 177 to 191 with an extra tyrosine at the start. In growth hormone, position 176 is a phenylalanine. So the two differ in one building block. The published animal studies were done with AOD9604.59

What do the animal studies show?

In obese mice growth hormone and AOD9604 reduced weight gain over 14 days and increased fat burning. In obese rats swallowed AOD9604 more than halved weight gain over 19 days, from 35.6 to 15.8 grams. Fat breakdown also rose in human fat tissue in the lab.234

Does it act like growth hormone on blood sugar and growth?

Not in the animal studies. AOD9604 did not bind to the growth hormone receptor and did not stimulate growth in cells. Unlike growth hormone it did not raise blood sugar or lower insulin release.2

What role does the beta-3 receptor play?

In obese mice growth hormone and AOD9604 raised the amount of beta-3 receptor in fat to the level of lean animals. In mice without this receptor the effect was absent with long-term dosing, yet fat burning still rose briefly. The authors conclude that the effect does not run directly through it.1

Are there human studies?

None registered for fragment 176-191. The variant AOD9604 ran under the name LAT8881 in three small trials on nerve pain, migraine and back pain, phase 1 and 2. ChEMBL lists it with highest phase 2. There are no published human data on weight loss with the fragment.678

Is AOD9604 on the doping list?

Yes. AOD9604 is banned by the World Anti-Doping Agency. There is a urine test for doping control. A stable breakdown product in the blood extends the detection window.5

Glossary

Terms explained briefly

Dotted words in the text open these explanations directly.

AOD9604
Modified end piece of growth hormone (positions 177 to 191 plus tyrosine), used in most animal studies.
Beta-3 adrenergic receptor
Receptor on fat cells through which adrenaline drives fat breakdown.
Fragment
A piece of a larger protein, here the last 16 building blocks of growth hormone.
GH receptor
Docking site for growth hormone. Growth, IGF-1 and the effect on blood sugar run through it.
IGF-1
Insulin-like growth factor 1, through which many growth effects of growth hormone run.
Lipogenesis
New formation of fat in the body, for example from sugar.
Lipolysis
Breakdown of stored fat into free fatty acids.
Lyophilisate
Freeze-dried powder. Without water a peptide keeps much longer.
Preclinical
Research before first use in humans, in cells and animals. Results cannot be transferred directly.
Subcutaneous
Into the fat layer just under the skin.
Zucker rat
Rat strain that becomes obese due to a gene defect. The name comes from the researchers Zucker.

Evidence

Sources

Show all 9 sourcesHide sources 5 Studies2 Trial registry2 Database checked 26 Oct 2026

Studies

  1. Growth hormone and AOD9604 in obese mice and mice without the beta-3 receptor

    Heffernan et al., Endocrinology, 2001

    DOI 10.1210/endo.142.12.8522 PMID 11713213
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  2. Fat burning and weight on AOD9604, without binding to the GH receptor (mice)

    Heffernan et al., International Journal of Obesity, 2001

    DOI 10.1038/sj.ijo.0801740 PMID 11673763
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  3. Swallowed AOD9604 in obese rats

    Ng et al., Hormone Research, 2000

    DOI 10.1159/000053183 PMID 11146367
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  4. Swallowed GH fragment in mice and in human fat tissue

    Heffernan et al., American Journal of Physiology Endocrinology and Metabolism, 2000

    DOI 10.1152/ajpendo.2000.279.3.E501 PMID 10950816
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  5. Structure, detection and breakdown of AOD9604

    Cox et al., Drug Testing and Analysis, 2015

    DOI 10.1002/dta.1715 PMID 25208511
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed

Trial registry

  1. Search on ClinicalTrials.gov (no trial of the fragment)

    ClinicalTrials.gov, U.S. National Library of Medicine

    Checked 26 Oct 2026 via ClinicalTrials.gov API v2
  2. Trials of AOD9604 as LAT8881 in the registry

    ClinicalTrials.gov, NCT03865953, NCT04153409, NCT05298306

    Checked 26 Oct 2026 via ClinicalTrials.gov API v2

Database

  1. AOD9604 (LAT-8881) in ChEMBL

    ChEMBL, EMBL-EBI (CHEMBL6068615)

    Checked 26 Oct 2026 via ChEMBL
  2. Growth hormone sequence in UniProt

    UniProt, Eintrag P01241 (GH1)

    Checked 26 Oct 2026 via UniProt

In the shop

HGH Fragment 176-191 in the catalog

Sizes, prices and shipping times are on the product page.

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