Fat Loss · 5mg × 10 vials
it was designed to be "HGH for fat loss only, without the growth side effects", and on the clean side-effect promise it delivers, but on the human fat-loss promise the evidence is thin.
HGH Fragment 176-191 is a synthetic 16-amino-acid peptide corresponding to the C-terminal residues 176-191 of human growth hormone, the unmodified native sequence (Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe). It is the "parent" fragment that AOD-9604 was derived from. The key distinction from AOD: AOD-9604 has an additional N-terminal tyrosine added (making it Tyr-176-191, technically a 17-residue analog) which was bolted on by Metabolic Pharmaceuticals to improve serum stability and allow radiolabeling for tracer studies. Native 176-191 has no such modification. Mechanistically the two compounds work through the same pathway: in adipocyte models the fragment stimulates lipolysis (fat breakdown) and inhibits lipogenesis (fat storage), and in rodent studies it upregulates beta-3 adrenergic receptor expression, mimicking the lipolytic arm of full HGH without engaging the growth, IGF-1, or insulin pathways. The receptor it binds in adipose tissue is high-affinity but still not formally characterized in humans (it is NOT GH-R and NOT B3-AR directly). In plain language: it was designed to be "HGH for fat loss only, without the growth side effects", and on the clean side-effect promise it delivers, but on the human fat-loss promise the evidence is thin. The native fragment is less stable in circulation than the tyrosine-modified AOD, with a shorter functional half-life, which is why community dosing often skews toward twice-daily rather than once-daily.
Typical dose ranges by experience level — educational reference. Message us and we tailor it to you.
5 mg vial + 2 ml BAC = 2.5 mg/ml, so 250 mcg = 0.10 ml = 10 IU on a U-100 syringe. Inject SubQ into abdomen on empty stomach, wait 30+ min before food. One 5 mg vial = 20 days at this dose. One 5 mg kit (10 vials) = 200 days at 250 mcg/day.
500 mcg = 0.20 ml = 20 IU on a U-100 syringe (at 2.5 mg/ml). One 5 mg vial = 10 days at 500 mcg/day; a 5 mg kit (FR5) = 100 days. Split dosing is anecdotal community optimization, no formal trials of native 176-191 exist at this depth.
1000 mcg/day = 0.40 ml total daily volume on a U-100 syringe. There is no published human data supporting doses above 1 mg/day for native 176-191 (the closest reference is the failed AOD-9604 Phase 2b which tested up to 1 mg/day with no efficacy gain). Most experienced users at this dose tier are running 176-191 as part of a stack (with HGH, CJC+Ipa, Tesa, or a GLP-1), not as a standalone.
Straight talk — what people actually report, and what the studies measured.
Peer-reviewed studies and clinical guidelines — tap any to read the source.
of human growth hormone, Horm Res 2000](https://pubmed.ncbi.nlm.nih.gov/11146376/) — mechanism work on the C-terminal fragment lineage, Bornstein/Ng Metabolic Pharmaceuticals origin, foundational native-fragment lipolytic characterization
Read study ↗PubMedNg FM, Bornstein J et al, The lipolytic effects of a synthetic peptide corresponding to residues 177-191 of human growth hormone in adipocytesHeffernan/Ng acute-dose lipolysis characterization, the original native-fragment in-vitro and rodent work
Read study ↗PubMedNg FM et al, A novel anti-obesity peptide, AOD9604, in pre-clinical and clinical evaluationdevelopment summary including beta-3 adrenergic receptor upregulation finding and the native-to-modified transition
Read study ↗PubMedStier et al, Safety and tolerability of the hexadecapeptide AOD9604 in humans, J Endocrinol Invest 2013 (PMC3979506)](https://pmc.ncbi.nlm.nih.gov/articles/PMC3979506/) — Phase 2a safety study on the tyrosine-modified analog, the closest formal human safety reference for the fragment family
Read study ↗Clinical contextMetabolic Pharmaceuticals AOD-9604 Phase 2b 12-week obesity trial archivePhase 2b missed primary endpoint, 536 patients, no statistically significant weight loss vs placebo. Native 176-191 has no equivalent Phase 2 of its own, this is the closest human efficacy reference for the lineage.
Read study ↗Physician commentaryPeptide Sciences HGH Fragment 176-191 referenceclinical profile summary; oversold marketing tone, useful as counter-reference for honest framing
Read study ↗Aggregated sentiment from public forums & socials — real-world reports, not individual endorsements.
Most common report: "didn't notice anything." Dominant signal across r/Peptides, r/PeptideArchive, and TikTok peptide reviews. Many users complete an 8-12 week cycle with no visible change.
A minority report mild appetite suppression and modest cuts to belly fat over 8-12 weeks at 500 mcg/day or 250 mcg 2× daily, usually when paired with fasted cardio and a caloric deficit. Hard to separate from the deficit itself.
Mild fatigue or "blunted energy" in the first week, usually resolves
Rare reports of mild flushing or warmth after injection
Some community users report native 176-191 feels "weaker" or shorter-acting than AOD-9604 at the same dose, which lines up with the shorter functional half-life of the unmodified peptide. Others report no perceptible difference. Inconsistent.
Common discontinuation reason: "not seeing results", switched to GLP-1 or HGH
Route: SubQ
Injection site: abdomen subQ, rotate sites; community convention is to inject into adipose tissue closest to target area (no human evidence this localizes the effect, but it is the standard protocol)
Storage: refrigerated, ~30 days after reconstitution; unreconstituted vials stable refrigerated long term
Notes: Administered AM fasted, ideally 30+ minutes before any food or workout. Native fragment has a shorter functional half-life than AOD-9604 (~10-30 min in circulation), so the fasted window is even more critical, glucose/insulin in circulation blunts the lipolytic signal. Many community protocols split into AM fasted + pre-workout (or AM fasted + pre-bed) precisely because the single-dose window is short. Light-sensitive after recon, keep in original vial in fridge.