Fragment 176-191 // The OG Fat Fragment
The original growth hormone fat-burning fragment — amino acids 176-191 of human GH, isolated for pure lipolysis without growth-promoting or metabolic side effects. Research shows 12.5x more potent fat oxidation than full GH. Twice-daily fasted dosing is critical.
The original fat fragment.
Fragment 176-191 is where GH fragmentology began. Researchers discovered that amino acids 176-191 contain the entire lipolytic machinery of growth hormone, and when isolated, this fragment is 12.5x more potent at fat oxidation than full-length GH — without any other systemic effects.
Twice daily. Always fasted.
Fragment 176-191 has a very short half-life (~30 minutes), which is why twice-daily fasted dosing is non-negotiable. Insulin destroys the fragment — inject after eating and you get zero effect.
The original GH fragmentology breakthrough.
Fragment 176-191 emerged from research isolating which portion of GH drives fat metabolism. The finding was definitive: amino acids 176-191 contain the entire lipolytic machinery, and the fragment is 12.5x more potent at fat oxidation than full GH — without systemic effects.
Clinical data is limited vs GLP-1 agonists, but the mechanism is among the best-understood in peptide science. AOD-9604 was later developed as a stabilized modification, adding tyrosine and earning TGA approval in Australia.
How it stacks against the competition.
| Compound | Receptors | Weight Loss | Half-Life | FDA Status |
|---|---|---|---|---|
| Fragment 176-191 | Raw GH Fragment | Moderate | ~30 min | Research |
| AOD-9604 | Modified Fragment | Moderate | ~30 min | TGA-Approved (AU) |
| Semaglutide | GLP-1 | ~15–17% | ~7 days | FDA Approved |
| 5-Amino-1MQ | NNMT Inhibitor | Mild-Moderate | Not characterized | Research |
What to watch for.
Fragment 176-191's side effect profile requires careful monitoring. One of the cleanest profiles available — virtually no systemic effects at standard doses.
- Minimal side effects (very clean profile)
- Injection site irritation (mild)
- Occasional mild headache
- Rare: hypoglycemia if combined with glucose-lowering agents while fasted
- No water retention, joint problems, or blood sugar impact
- Shorter reconstituted shelf life than most peptides
- Fasting glucose and insulin
- Lipid panel
- Standard CBC / CMP baseline
- IGF-1 (should remain unchanged)
- Stacking with AOD-9604 debated — overlapping mechanism
- 5-Amino-1MQ for complementary NNMT pathway (best synergy)
- Tesofensine for appetite + Fragment for lipolysis
- CJC-1295/Ipamorelin for GH beyond fat
- GLP-1 agonists for appetite + Fragment for lipolysis
- Must be taken fasted — insulin destroys the fragment
- Refrigerate reconstituted at 2–8°C
- More fragile — use within 21 days
- Do not freeze reconstituted solution
- Protect from light
- Gentle reconstitution — stream BAC water down vial wall
- Confirm fragment sequence (aa 176-191) on COA
Compounds that complement Fragment 176-191.
Fragment 176-191 targets a single narrow pathway, making it complementary with virtually any other fat loss mechanism.
The purest fat-loss tool in the peptide toolkit.
Fragment 176-191 is as targeted as it gets — one function, zero systemic effects, minimal side effects. Won't produce GLP-1 level results, but adds a clean lipolysis layer to any protocol. The twice-daily fasted dosing and short shelf life make it more demanding than AOD-9604. If you want the original research compound, choose Fragment. If you want the stabilized version, choose AOD-9604. Pair with 5-Amino-1MQ for meaningful synergy.
Our free 50-page Protocol Guide includes the complete Metabolic Fat Loss Stack with Fragment 176-191 — titration schedules, stacking recommendations, blood work panels, and tracking templates.