HGH Fragment 176-191: Dosing Protocols

Research Dosing Disclaimer#

The dosing information below is derived from research studies and is provided for educational purposes only. HGH Fragment 176-191 is not approved for human use, and no official dosing guidelines exist.

Dose-Response Data#

Summary. Across obese mouse and rat models, hGH fragment 176–191 and close analogs (AOD‑9401, AOD‑9604) have been tested at per‑kg standardized doses ranging from sub‑mg/kg/day (chronic implants in rats) to hundreds of mg/kg/day (oral or continuous infusion in mice). Chronic regimens consistently reduce weight gain and adiposity and increase lipolysis/fat oxidation without the diabetogenic effects seen with intact hGH; acute high single doses transiently increase energy expenditure/fat oxidation with minimal glycemic disruption. Formal multi‑arm dose–response curves are limited; most studies report single effective doses, with some acute ranges and toxicology ranges suggesting thresholds.

Key animal dose regimens and outcomes (normalized per kg).

• Mouse, ob/ob (C57BL/6J), oral AOD‑9401 500 mg/kg/day for 30 days: ~58% reduction in cumulative weight gain from day 16; no change in food intake or resting energy expenditure; plasma free fatty acids increased; ex vivo adipose lipolysis increased and lipogenesis decreased; plasma glucose and triglycerides slightly lower but not significant (body‑weight normalized as mg/kg/day).
• Mouse, ob/ob and lean C57BL/6J, continuous s.c. infusion via mini‑osmotic pump, AOD‑9604 250 mg/kg/day for 14 days: in ob/ob mice, blunted weight gain, increased circulating glycerol, and fat oxidation increased by ~216% (AOD‑9604) versus baseline; no change in glucose oxidation, plasma glucose, or insulin. In contrast, hGH 1 mg/kg/day induced marked hyperglycaemia and ~66–71% insulin reduction with depressed glucose oxidation.
• Mouse, ob/ob (acute metabolic test), single intraperitoneal AOD‑9401 250 mg/kg: energy expenditure +45% at ~18 min; fat oxidation +83%; transient 2.4‑fold increase in glucose oxidation at ~9 min that dissipated by 15 min.
• Rat, Zucker fatty (fa/fa), slow‑release s.c. implant delivering ~450 µg/kg/day of AOD‑9401 for ~20 days: reduced cumulative weight gain; smaller adipocyte diameters; reduced ex vivo lipogenesis; typical daily intraperitoneal regimens in this model yield ~7–10% weight loss. Hyperinsulinemic clamp after 28 days at 500 µg/kg/day did not show impaired glucose tolerance or insulin responsiveness.
• Rat, Zucker fatty (acute), single intravenous AOD‑9401 250–1000 µg/kg: only marginal, transient hyperglycaemia at 1000 µg/kg (∆~0.6 ± 0.3 mM at 30 min), returning to baseline within 3 h; lower doses showed minimal glycemic effect.
• Rat, 4‑week IV toxicology (not efficacy), AOD‑9604 at 0.1, 1.0, 10 mg/kg/day: no treatment‑related deaths; female rats showed reduced body‑mass gain at 1 and 10 mg/kg/day; rapid IV plasma degradation (ex vivo t1/2 ~4 min). These findings suggest potential body‑mass effects at ≥1 mg/kg/day in some settings but are not formal efficacy endpoints.
• Pig, single‑dose PK (not efficacy), IV 400 µg/kg and oral 2000 µg/kg AOD‑9604: very short IV half‑life (~3–4 min) and measurable oral exposure (Tmax ~60 min). No metabolic outcomes reported.

Dose–response patterns and thresholds.

• Acute in vivo dose range: 250–1000 µg/kg IV in rats produced only marginal glycemic effects at the top dose, supporting a favorable acute safety window for glycemia; acute IP 250 mg/kg in mice robustly increased energy expenditure and fat oxidation within minutes. Formal graded in vivo efficacy curves are not reported, but adipose ex vivo assays show dose‑dependent increases in glycerol release and inhibition of lipogenesis over 0.1–10 µM, with apparent plateaus near the upper range.
• Chronic efficacy windows: effective chronic doses include ~450–500 µg/kg/day in rats via implant or study clamp context and 250–500 mg/kg/day in obese mice by infusion or oral routes, respectively. Within these reported single‑dose regimens, outcomes consistently include reduced weight gain/adiposity and increased fat oxidation/lipolysis without worsening glycemia or insulin in fragment/analog‑treated animals; by contrast, intact hGH at 1 mg/kg/day induces hyperglycaemia and insulin reduction. Multi‑arm dose–response plateaus or EC50 estimates were not provided.

Normalization and comparability.

• All studies reported doses normalized per kg body weight (mg/kg/day for chronic, mg/kg or µg/kg for acute). Species/strains: C57BL/6J ob/ob and lean mice, Zucker fatty rats; routes included oral gavage, IP, continuous s.c. infusion, s.c. slow‑release implant, and IV bolus or daily IV. These facilitate cross‑study comparison on a mg/kg basis.

Embedded summary table of animal doses and outcomes:

Limitations. Most preclinical studies report single effective doses rather than full dose–response series; thus, thresholds and plateaus are inferred mainly from acute ex vivo dose ranges and the presence of effects at specific chronic doses. Toxicology studies provide higher‑dose exposure ranges but lack metabolic endpoints.

Administration Routes#

We compared the pharmacokinetics (PK) and apparent bioavailability of HGH Fragment 176–191 (AOD9604) by administration route, focusing on subcutaneous (SC), oral, intramuscular (IM), and topical delivery. Evidence includes quantitative IV and oral data in pigs and in vitro/ex vivo metabolism, with limited or no primary PK for SC, IM, or topical.

Oral administration

• Bioavailability and absorption: Oral dosing achieves measurable systemic exposure with slower absorption than parenteral dosing. In pigs given 2 mg/kg by gavage, plasma AOD9604 reached Cmax ≈ 1,127 (as reported) at ≈60 min (Tmax), with a markedly larger AUC than IV despite the higher oral dose; tissue levels after oral dosing peaked around 30 min in whole‑body radiography, indicating uptake and distribution.
• Pharmacokinetics: Oral absorption is protracted vs IV; circulating material includes intact peptide and sequentially N‑terminally truncated fragments (−2aa, −3aa predominant), reflecting rapid enzymatic processing after entry. The data support oral bioavailability but exact human oral F% is not established here.

Subcutaneous administration

• Evidence gap: We found no primary quantitative SC PK (Cmax/Tmax/half‑life/F%) for AOD9604. Secondary sources note SC use in practice, but do not report PK parameters. Given the peptide’s rapid plasma degradation observed ex vivo/in vivo, SC absorption would likely produce a short systemic exposure window with rapid truncation similar to IV once in circulation; however, this remains inferential without direct PK data.

Intramuscular administration

• Evidence gap: No primary IM PK data were identified. As with SC, systemic exposure after IM would be expected to be brief once the peptide enters the circulation due to rapid degradation, but quantitative parameters are unavailable in the sources retrieved.

Topical administration

• Evidence gap: We found no quantitative topical PK data (percutaneous absorption, bioavailability, or plasma PK) for AOD9604. Available reviews mention the molecule but provide no absorption metrics or detection data for topical delivery.

IV reference (for context)

• In pigs (400 µg/kg IV), AOD9604 showed extremely rapid plasma kinetics: Tmax ≈ 2 min, Cmax ≈ 1,945 (as reported), and a serum half‑life ≈ 3 min, with near‑complete disappearance from plasma by about 12 min; widespread tissue distribution occurred within 5 min except the CNS.

Metabolism, detection, and handling considerations

• Rapid degradation in plasma/blood: In spiked rat plasma at room temperature, intact AOD9604 had an approximate half‑life ~4 min, with extensive N‑terminal truncation and little intact peptide detectable by ~56 min; ex vivo handling (heparinization, chilling) markedly affects recovery.
• In vivo circulating species: After both IV and oral dosing in pigs, multiple truncated fragments appear rapidly in plasma, predominated by −2aa and −3aa species, consistent with fast systemic proteolysis.

Comparative summary across routes

• Oral: Demonstrated systemic exposure with slower absorption (Tmax ~60 min in pigs) and substantial AUC relative to IV in the animal model; circulating peptide is rapidly processed into shorter fragments.
• SC: No direct PK or bioavailability data identified; likely brief systemic exposure post‑absorption with rapid degradation similar to IV once in plasma, but this is not quantitatively established.
• IM: No direct PK or bioavailability data identified; expectations mirror SC, with the same caveat about absence of measured parameters.
• Topical: No evidence of percutaneous bioavailability metrics; topical PK remains uncharacterized in the located literature.

Limitations

• The most detailed quantitative PK data are from pigs (IV and oral) and may not extrapolate directly to humans. We did not identify primary PK studies quantifying SC, IM, or topical absorption for AOD9604; therefore, those routes’ bioavailability and PK remain uncertain in the available evidence set.

Human-Equivalent Dosing#

Allometric methods in the broader literature. Methodological reviews clarify that body‑surface‑area (BSA/Km) conversions are intended to estimate conservative human‑equivalent doses (HEDs) for first‑in‑human safety from animal NOAELs, not to translate efficacy doses; they highlight frequent inaccuracies if used to predict therapeutic doses and emphasize alternatives such as classical allometry based on PK parameters and physiologically based pharmacokinetic (PBPK) modeling. As an example of practice, an unrelated pharmacology study explicitly used the Reagan‑Shaw/FDA BSA method to convert human doses to rat doses, illustrating the Km‑based approach employed in research; however, this is not specific to AOD9604.

Conclusion. For HGH Fragment 176‑191/AOD9604, the only explicit interspecies “scaling” identified in primary studies is molar‑equivalent dosing in a rabbit intra‑articular model, with dose concentration estimated from joint volume. Human clinical doses (e.g., 1 mg oral daily) are reported without documented translation from animal doses. In the broader literature, BSA/Km HED conversion (Reagan‑Shaw/FDA) is commonly cited for conservative first‑in‑human safety starting doses, while PK allometry and PBPK modeling are recommended for therapeutic translation; however, explicit application of these methods to AOD9604 dose selection was not found in the available sources.

Evidence Gaps#

• No human dose-finding studies have been completed
• Allometric scaling from animal models has inherent limitations
• Route-specific bioavailability data in humans is absent
• Optimal treatment duration has not been established

Related Reading#

• HGH Fragment 176-191 overview and research guide
• HGH Fragment 176-191 side effects profile
• HGH Fragment 176-191 research evidence