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DPreclinical / mechanistic only

HGH Fragment 176-191

AOD fragment

HGH Fragment 176-191 (AOD9604) is a synthetic modified C-terminal fragment of human growth hormone — hGH(177-191) with an added N-terminal tyrosine, hence "hGH 176-191" — engineered to mimic GH's lipolytic (fat-mobilizing) domain while avoiding GH-receptor-mediated growth and IGF-1 signaling. It is marketed to physique/fat-loss and "joint repair" users, but its purported human benefits are essentially unproven: efficacy data come almost entirely from rodent studies and one sponsor-run 24-week oral obesity trial (n≈502 randomized) that failed its primary weight-loss endpoint and was never published as a peer-reviewed RCT. It is not approved by any major regulatory agency for any indication and appears on the FDA "Category 2" Bulk Drug Substances list over immunogenicity concerns. The main real-world dangers are not a distinct toxidrome but rather the unregulated, non-pharmaceutical supply (unknown identity, purity, sterility, endotoxin), injection-site and possible allergic/immunogenic reactions, and the false confidence created by "GH-like" marketing when robust human safety and efficacy data simply do not exist. Anyone using this should treat it as an experimental compound of unproven benefit and work with a clinician.

Clinical readoutPeptide · gh-fragment
Hepatic strainNone
CardiovascularNone
HPTA suppressionNone
Half-life
Not adequately ch…
Route
As-reported: originally…
Evidence
D
Active
Unknown/undefined in hu…
1·t½2·t½3·t½4·t½5·t½
Illustrative single-compartment washout · each mark = one half-life · t½ ≈ Not adequately characterized in humans; not reported in the peer-reviewed human trial literature. As a small unmodified peptide it is expected to be rapidly degraded (short plasma residence, on the order of minutes), but no validated human half-life value exists.
Pharmacology

Mechanism of action

AOD9604 corresponds to the C-terminal lipolytic region of human growth hormone (residues ~177-191 plus an N-terminal tyrosine). In preclinical models it stimulates lipolysis and fat oxidation and reduces body-weight gain in obese/ob-ob mice and Zucker rats, but, unlike full-length GH, it does not bind the GH receptor and does not drive GH-receptor-mediated cell proliferation, and it did not raise blood glucose or impair insulin sensitivity in rodents. Its lipolytic action is not mediated directly through the beta-3 adrenergic receptor, though chronic treatment increased beta-3-AR mRNA expression in adipose tissue of obese mice, which may enhance lipolytic sensitivity. In humans, though, it shows minimal systemic GH/IGF-1 axis activation and no meaningful IGF-1 elevation, so the somatotropic/anabolic mechanism assumed by many users is not supported. Proposed cartilage/joint-regenerative actions are based only on animal intra-articular studies and lack a defined human mechanism.
Kinetics

Pharmacokinetics

Half-life

Not adequately characterized in humans; not reported in the peer-reviewed human trial literature. As a small unmodified peptide it is expected to be rapidly degraded (short plasma residence, on the order of minutes), but no validated human half-life value exists.

Active duration

Unknown/undefined in humans. Preclinical anti-obesity effects required chronic daily dosing, implying no meaningful depot or long duration of action.

Route

As-reported: originally developed as an oral anti-obesity drug (oral bioavailability is poor and the oral program failed). Single-dose human pharmacology used intravenous administration (reported 25-400 micrograms IV). Non-medical users self-administer subcutaneously. Preclinical work used oral, intraperitoneal, subcutaneous and intra-articular routes. Route/PK data are for monitoring and washout context only, not for evading drug testing.

Metabolism & clearance

Presumed proteolytic degradation to constituent amino acids/peptide fragments (typical for short peptides); specific human metabolism and renal/hepatic clearance pathways are not defined in the published literature.

For monitoring and washout planning, not drug-test evasion.

Reported effects

Physiological & performance effects

  • Preclinical (rodent) only: increased lipolysis, increased fat oxidation, and reduced body-weight gain in obese mice and Zucker rats with chronic dosing
  • Preclinical: increased adipose beta-3 adrenergic receptor mRNA expression
  • In humans: no demonstrated clinically meaningful weight loss or fat loss — a 24-week oral obesity trial failed its primary endpoint
  • In humans: no meaningful IGF-1 elevation and minimal GH/IGF-1 axis activation (i.e., it does not act like injected GH)
  • Preclinical (rabbit): intra-articular AOD9604, especially combined with hyaluronic acid, improved cartilage/lameness outcomes in a collagenase osteoarthritis model — animal data only, no human joint-repair evidence
  • Claimed physique 'recomposition,' performance, and joint-repair benefits in humans are unproven and speculative
Safety

Adverse effects by system

Cardiovascular

No specific cardiovascular toxicity signal has been established in humans; there are no controlled human cardiovascular outcome data. Absence of reported harm reflects absence of adequate study, not proven safety.

Hepatic

No hepatotoxicity signal reported and no human liver-outcome data exist. Unlike oral 17-alpha-alkylated steroids, there is no mechanistic basis for direct hepatotoxicity, but this has not been formally studied in humans.

Endocrine / HPTA

Distinct from GH: minimal GH/IGF-1 axis activation and no meaningful IGF-1 elevation observed in humans. In preclinical models it did not cause the hyperglycemia or insulin resistance seen with full-length GH. It has no described action on the hypothalamic-pituitary-gonadal (testosterone) axis and is not a sex-steroid/SERM-type agent.

Reproductive

No reproductive or fertility data in humans; not studied. No known direct effect. Unknown/avoid in pregnancy and breastfeeding due to absent data.

Neuropsychiatric

No psychiatric adverse effects attributable to AOD9604 have been documented; no human data. (Note: broader GH-IGF peptide classes have reported mood/appetite changes, but these are not established for AOD9604 specifically.)

Renal

No renal adverse-effect data in humans; not studied. Unknown.

Hematologic

No hematologic adverse-effect data in humans; not studied. Unknown.

Dermatologic

Injection-site reactions are plausible with subcutaneous self-administration (reported across this peptide class); AOD9604 is on the FDA 'Category 2' Bulk Drug Substances list partly over immunogenicity, so local/allergic and hypersensitivity reactions are a theoretical-to-plausible risk. Rare allergic reactions/peripheral edema are reported for GH-axis peptides generally.

Recovery

HPTA suppression & recovery

Suppression: No known suppression of the hypothalamic-pituitary-gonadal (testosterone) axis; not an androgen, anabolic steroid, or SERM

AOD9604 is not known to suppress endogenous testosterone or gonadotropins, so SERM-based post-cycle recovery concepts do not apply to this compound. It also does not require and should not be paired with a SERM. If a user is combining it with anabolic-androgenic steroids (a common but separate practice), any HPTA suppression comes from those steroids, not from AOD9604 — and any recovery question in that scenario must be directed to an endocrinologist rather than self-managed. Do not initiate any hormonal 'recovery' protocol without endocrinology input.

Bloodwork & vitals

Monitoring

Recommended labs & checks
Fasting glucose and HbA1c (baseline and periodic) — to detect dysglycemia, especially if stacked with other GH-axis agentsIGF-1 (baseline and on-cycle) — expected to remain near baseline; a rise suggests contamination with GH/secretagogues or a mislabeled productComprehensive metabolic panel including liver and renal function (baseline and periodic)Lipid panel (baseline and periodic)CBC (baseline)

Cadence: Baseline before any use; re-check metabolic labs roughly every 8-12 weeks while using and if new symptoms develop. Because efficacy is unproven, the primary purpose of monitoring is safety surveillance, not optimization.

Warning signs — seek care
  • Signs of allergic/hypersensitivity reaction: rash, hives, swelling, wheezing, or anaphylaxis — stop and seek emergency care
  • Injection-site infection: spreading redness, warmth, pus, fever — seek medical care
  • New or worsening high blood sugar symptoms (excess thirst, urination, blurred vision)
  • Unexplained persistent edema, palpitations, or shortness of breath
  • Any severe or unexpected systemic reaction after dosing, which may indicate an adulterated or contaminated product
Do not use if

Contraindications

  • Pregnancy and breastfeeding (no safety data)
  • Known hypersensitivity to the peptide or formulation excipients (immunogenicity is a flagged concern; compound is on the FDA Category 2 Bulk Drug Substances list)
  • Active or history of malignancy — use with caution/avoid, since although AOD9604 itself shows no GH-receptor proliferative activity or IGF-1 elevation, mitogenic concerns for GH-axis-marketed peptides are unresolved and product identity in the unregulated market is unverifiable
  • Any use of non-pharmaceutical-grade / 'research use only' product of unknown identity, purity, sterility, or endotoxin content
  • Self-treatment of obesity or joint disease in place of evidence-based, clinician-directed care (no proven human efficacy)
Combinations

Interaction profile

  • ContraindicatedWith DNP: Additive cardiovascular strain

Check a specific combination in the interaction checker.

Harm reduction

Reducing harm & when to stop

  • Understand the evidence gap first: human benefit is unproven — the pivotal human obesity trial failed, and joint/physique claims rest on rodent data. This is an experimental compound, not a validated therapy.
  • The largest concrete risk is the unregulated supply: 'research-use' vials have no guaranteed identity, dose, purity, sterility, or endotoxin control. A product may be underdosed, mislabeled, or contaminated (including with GH or secretagogues that would raise IGF-1).
  • Do not use in pregnancy, breastfeeding, with active malignancy, or with known peptide hypersensitivity.
  • Involve a clinician and get baseline bloodwork (glucose/HbA1c, IGF-1, metabolic and liver/renal panels) before and during use; an IGF-1 rise is a red flag for a contaminated/mislabeled product.
  • Stop immediately and seek care for signs of allergic reaction (rash, swelling, wheezing), injection-site infection (spreading redness, pus, fever), new hyperglycemia symptoms, or any severe systemic reaction.
  • Do not use AOD9604 as a substitute for evidence-based management of obesity or joint disease.
  • This compound does not suppress testosterone and does not call for any SERM or hormonal 'recovery' protocol; any HPTA questions arising from concurrent steroid use must go to an endocrinologist.
  • No guidance here is about maximizing effect, dosing to a target, or obtaining the product — only about reducing harm and knowing when to seek medical care.
Evidence

Citations (11)

Every clinical claim above is tied to a primary source. Overall evidence grade D — this compound lacks adequate human data; claims rest on preclinical or mechanistic evidence.

  1. 01

    AOD9604 is a synthetic modified C-terminal fragment of human GH (hGH 177-191 plus an N-terminal tyrosine, labeled 'hGH 176-191'), designed to mimic GH's lipolytic domain while avoiding GH-receptor-mediated growth and IGF-1 signaling.

    ReviewThe emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration.DOI 10.3389/fendo.2026.1822475 ↗

  2. 02

    In humans, AOD9604 shows minimal systemic GH/IGF-1 axis activation and no meaningful IGF-1 elevation.

    ReviewThe emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration.DOI 10.3389/fendo.2026.1822475 ↗

  3. 03

    A 24-week oral anti-obesity trial (n=534, ~502 randomized) failed to demonstrate a significant benefit on the primary weight-loss endpoint; efficacy conclusions rest on sponsor-reported phase 2 outcomes rather than peer-reviewed RCTs, so there are no robust human data supporting fat loss, recomposition, or performance benefit.

    ReviewThe emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration.DOI 10.3389/fendo.2026.1822475 ↗

  4. 04

    AOD9604 is not approved by major regulatory agencies for any indication and is on the FDA 'Category 2' Bulk Drug Substances list, partly over immunogenicity concerns.

    ReviewThe emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration.DOI 10.3389/fendo.2026.1822475 ↗

  5. 05

    Reported (as-observed, not endorsed) administration patterns: 25-400 micrograms single IV dose in pharmacology; 1 mg oral once daily for 12 weeks in obese patients; non-medical subcutaneous self-administration is described.

    ReviewThe emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration.DOI 10.3389/fendo.2026.1822475 ↗

  6. 06

    In obese and lean mice, both hGH and AOD9604 reduced body-weight gain, increased in vivo fat oxidation, and stimulated lipolysis; unlike hGH, AOD9604 did not induce hyperglycemia, did not compete for the hGH receptor, and did not induce cell proliferation.

    PreclinicalIncrease of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment.DOI 10.1038/sj.ijo.0801740 ↗

  7. 07

    The lipolytic actions of AOD9604 are not mediated directly through the beta-3 adrenergic receptor, but chronic treatment increased adipose beta-3-AR mRNA expression in obese mice.

    PreclinicalThe effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice.DOI 10.1210/endo.142.12.8522 ↗

  8. 08

    In obese Zucker rats, oral AOD9604 reduced body-weight gain and increased adipose lipolytic activity without adverse effects on insulin sensitivity (euglycemic clamp).

    PreclinicalMetabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone.DOI 10.1159/000053183 ↗

  9. 09

    Cartilage/joint-repair evidence is limited to animal work: intra-articular AOD9604, especially combined with hyaluronic acid, enhanced cartilage regeneration and reduced lameness in a collagenase-induced rabbit osteoarthritis model.

    PreclinicalEffect of Intra-articular Injection of AOD9604 with or without Hyaluronic Acid in Rabbit Osteoarthritis Model.PMID 26275694 ↗

  10. 10

    For therapeutic peptides used in orthopedics/musculoskeletal care (including AOD-9604), preclinical findings are promising but there is a current lack of clinical trials.

    ReviewDOI 10.5435/JAAOSGlobal-D-25-00236 ↗

  11. 11

    AOD9604 was in clinical development as an anti-obesity agent acting to increase adipose tissue breakdown (developmental status; no approval).

    ReviewObesity drugs in clinical development.PMID 16625817 ↗

Last reviewed 2026-07-06 · Verified against PubMed · Educational, not medical advice