Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of HGH Fragment 176-191 and Retatrutide — mechanism, side effects, legal status, and pricing.
HGH Fragment 176-191 is a synthetic 16-residue disulfide-cyclized peptide corresponding to the C-terminal region (residues 176–191) of human growth hormone. It is classified as a lipolytic/GH-fragment peptide, not a full growth hormone. The compound is prohibited at all times under WADA Section S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics). Not FDA-approved for any indication; clinical development of the related analogue AOD9604 was discontinued in 2007 after a pivotal Phase IIb obesity trial failed its primary efficacy endpoint.
HGH Fragment 176-191
Retatrutide
Category
Legal Status
Mechanism
Half-life
Side Effects
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HGH Fragment 176-191
No pricing data yet.
Check HGH Fragment 176-191 prices →Retatrutide
COA corpus from Disclosed Labs — independently tested batches only.
HGH Fragment 176-191
1
COAs
99.2%
Avg purity
1
Labs
Retatrutide
413
COAs
99.7%
Avg purity
17
Labs
No human data were found for the native peptide (CAS 66004-57-7, Phe176) itself. All identified human clinical work was conducted on AOD9604, a distinct N-terminal Tyr-substituted analogue: six sponsor-run, randomized, double-blind, placebo-controlled trials (Phase I–IIb, 2001–2006, ~900 total subjects, including a ~502-subject 24-week Phase IIb obesity trial) assessed safety and later weight-loss efficacy. Reported: good tolerability, no serious adverse events, no IGF-1 elevation—but the pivotal Phase IIb trial did not meet its primary weight-loss endpoint versus placebo and Metabolic Pharmaceuticals discontinued development in 2007. In obese Zucker rats, oral AOD9604 (500 µg/kg/day × 19 days) reduced body-weight gain by >50% and increased adipose lipolytic activity without impairing insulin sensitivity. In obese and lean mice, both hGH and AOD9604 reduced weight gain and increased fat oxidation and plasma glycerol; unlike hGH, AOD9604 caused no hyperglycemia and did not compete for the hGH receptor. In β3-AR knockout mice, chronic lipolytic/weight effects were lost while acute energy-expenditure increases persisted. Intra-articular AOD9604 combined with hyaluronic acid outperformed either agent alone in a rabbit collagenase-induced knee osteoarthritis model.
Key references
Phase 2 obesity trial (Jastreboff et al., NEJM 2023; PMID 37366315) demonstrated up to 24.2% body weight loss at 48 weeks at the 12 mg dose, exceeding both semaglutide and tirzepatide. A Phase 2 type 2 diabetes trial (Rosenstock et al., Lancet 2023; PMID 37385280) showed robust HbA1c and weight reductions vs. placebo and dulaglutide. A Phase 2a MASLD trial (Sanyal et al., Nat Med 2024; PMID 38858523) demonstrated significant reductions in hepatic steatosis driven by glucagon receptor activation. Phase 3 TRIUMPH trials are ongoing (Eli Lilly), with results expected 2025–2026. Retatrutide is NOT FDA-approved as of April 2026 — it remains investigational.
HGH Fragment 176-191 and Retatrutide are both in the Metabolic category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Key references