# HGH Fragment 176-191

Growth-hormone tail fragment sold for fat loss; AOD-9604's near-twin, untested in humans and rarely felt.

- Page: https://peprank.xyz/peptides/frag-176-191
- Category: Metabolic & weight (Research peptide)
- Also known as: Frag 176-191; HGH Frag; hGH C-terminal fragment; YLRIVQCRSVEGSCGF (as usually sold)
- Routes: Injection / Nasal
- Safety tier: Strict: Caution · Balanced: Caution · Evidence only: Clean
- Risk axes (0 none to 3 severe): Seen harm 0, Mechanism 1, Data gap 3, Silent harm 1, Product 3
- Positive: 40% of 14 graded reports glowing or positive, shrunk toward the 49% all-report average by 8 reports' weight
- Rank: #23 of 61 research peptides
- Graded reports: 14 (Positive 5, Mixed 1, Nothing 4, Negative 4)
- Evidence: Animal only — Rat and mouse work only (the bare 177-191 fragment was antilipogenic but not lipolytic in rat fat pads). The human trials belong to AOD-9604, the Tyr-modified analogue: six trials, about 900 people, placebo-like safety, no IGF-1 or glucose change and no weight loss.
- Access: Grey market
- Onset: Users who credit it describe fat loss over 3-4 weeks; nothing is felt per dose.
- Lasts: Short-acting; injected once or twice daily, usually in 4-8 week cycles.
- Cost per month: ≈ €27–72 (researchers' estimate)
- Updated: 2026-10-30

## What users report

Mixed and heavily confounded. About a third report fat loss or a better body composition, but every one of those was dieting hard or also on CJC-1295/ipamorelin, BPC-157, retatrutide or tirzepatide; the cleanest positive is a month of 150 mcg nasal frag with portion control and 1.5-2 h of daily training. Another third felt nothing and say real GH or a GLP-1 does far more. The rest are negatives: vials that gel or turn cloudy so they cannot be used, weight gain on a GH-peptide stack, and appetite returning on a frag/CJC/ipa blend. A week of mild headaches is the one side effect mentioned. Experienced users repeat that it is the same thing as AOD-9604, which lost to placebo. Felt nothing: 5 of 15 reports felt nothing; 4 more were negative.

**Effects:** fat loss in 'trouble areas' (confounded by diet and other drugs); reported body-composition change on frag/CJC/ipamorelin blends

**Downsides:** no noticeable effect for many; vials gel or go cloudy after reconstitution; mild headaches in the first week (one report); appetite and bloating on blends (one report)

**Risks:** No human data at all for the fragment; its safety record is borrowed from AOD-9604, which differs by one residue; Grey-market injectable: purity, sterility and aggregation (gelling) unverified; aggregated peptide raises immunogenicity concerns; Prohibited in sport at all times (WADA S2.2.3, named explicitly)

**Caveat:** Read with the AOD-9604 entry: the two are one residue apart, and what is sold as 'Frag 176-191' usually carries AOD's tyrosine anyway. AOD's six human trials found it safe and ineffective, and nothing suggests the fragment would differ, but the bare fragment itself has never been given to people in a study. It does not bind the GH receptor or raise IGF-1 in animals, which is why it is not treated as a GH-axis drug.

**Typical use:** 250-500 mcg subq once or twice daily, fasted (often before cardio), in 4-8 week cycles; one nasal user took 150 mcg a day. Not worth it on current evidence.

**Getting it:** Research-peptide vendors in 2-5 mg vials, often blended with CJC-1295 and ipamorelin; a few take it nasally. Despite the name, most vendors list the sequence YLRIVQCRSVEGSCGF, with tyrosine where native GH has phenylalanine at position 176, which is the AOD-9604 sequence; the vial is usually the same molecule as AOD-9604. Reconstitutes poorly: many vials gel or cloud in bacteriostatic water, and vendors advise acetic acid.

**Stacked with:** CJC-1295 and ipamorelin (Sold as a three-way blend; the positive blend reports cannot separate frag from the GH secretagogues.); Retatrutide or tirzepatide (Added to break a GLP-1 stall; users who tried it say the GLP-1 does nearly all the work.); AOD-9604 (Some stack both, which experienced users point out is the same peptide twice.)

## Risk profile

- **Seen harm 0/3:** Widely used grey-market for years, yet no serious adverse event appears in the literature or in first-hand reports (a week of mild headaches, bloating and unusable gelled vials are the worst). Use is undocumented rather than measured, so this is absence of reports, not proof of safety.
- **Mechanism 1/3:** Unlike GH and the secretagogues it does not bind the GH receptor, raise IGF-1, cause hyperglycaemia or drive cell proliferation in animal work, and the near-identical AOD-9604 left IGF-1 and glucose unchanged in people. What remains is speculative: immunogenicity from aggregated or impure peptide.
- **Data gap 3/3:** No human study has ever used the bare fragment. AOD-9604's six trials (about 900 people) bridge closely, since it differs only by tyrosine for phenylalanine at position 176 and is in practice the sequence most vendors ship under this name, but by the rubric an analogue's trials are not the sold molecule's.
- **Silent harm 1/3:** With no credible serious mechanism, rated on the plausible harms: injection-site and allergic reactions and headaches, mostly noticed at once and resolving on stopping.
- **Product 3/3:** Bought as grey-market injectable powder of unverified purity and sterility; it aggregates readily, and users report vials that gel or cloud in bacteriostatic water and vendors telling them to add acetic acid. A few use it nasally.
- **Never if:** Pregnancy or breastfeeding (no human data); Competitive athletes (prohibited at all times under WADA S2.2.3)

## Top reports

- Positive, metabolic, 150 mcg/day: “So far I've definitely seen a decrease in body fat and have slimmed down a lot in the trouble areas of the midsection. The first week there was about a week of mild headaches, but all has been good since then.” — [r/Peptidesource](https://www.reddit.com/r/Peptidesource/comments/1nb8za6/hgh_frag_a_month_in/)
- Positive, metabolic: “I’ve ran combos and frag before many times for different reasons with great results” — [r/Peptidesource](https://www.reddit.com/r/Peptidesource/comments/1hno38p/fragmentcjcipa/m43kju2/)
- Positive, metabolic: “I always use HGH frag during my cut season (summer time) and I really happy with results of course with a good diet, and training.” — [r/Biohackers](https://www.reddit.com/r/Biohackers/comments/1m2bfr7/i_cant_do_tst/)
- Positive, metabolic, blend of 6 mg frag, 3 mg CJC-1295, 3 mg ipamorelin per vial: “I've seen a some results with CJC+Ipa combo but then had great results with Fragment+CJC+Ipa combo it seems.” — [r/Peptidesource](https://www.reddit.com/r/Peptidesource/comments/1hno38p/fragmentcjcipa/)
- Positive, metabolic: “I do think I've seen a more noticeable change in my body composition with the frag mix.” — [r/BodyHackGuide](https://www.reddit.com/r/BodyHackGuide/comments/1svaybt/coming_off_of_reta/oiancnf/)

## Studies

- [Wu & Ng 1993: Antilipogenic action of synthetic C-terminal sequence 177-191 of human growth hormone](https://pubmed.ncbi.nlm.nih.gov/8358331/) (animal, 1993): The bare hGH 177-191 peptide matched intact GH's antilipogenic activity in rat fat tissue but had no significant lipolytic effect (no rise in glycerol release).
- [Ng et al. 2000: Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone](https://pubmed.ncbi.nlm.nih.gov/11146367/) (animal, 2000): The Tyr-modified analogue given orally to obese Zucker rats for 19 days halved weight gain and raised adipose lipolysis without harming insulin sensitivity, unlike intact GH.
- [Heffernan et al. 2001: Increase of fat oxidation and weight loss in obese mice by hGH or a modified C-terminal fragment](https://pubmed.ncbi.nlm.nih.gov/11673763/) (animal, 2001): AOD9604 reduced weight gain and raised fat oxidation in ob/ob mice; it did not bind the GH receptor, cause hyperglycaemia or drive cell proliferation.
- [Stier et al. 2013: Safety and tolerability of the hexadecapeptide AOD9604 in humans](https://doi.org/10.4021/jem157w) (review, n=925, 2013): Across six randomised trials of the near-identical AOD9604, side effects matched placebo and IGF-1 and glucose did not change; the closest human safety data for the fragment.
- [Metabolic Pharmaceuticals: Phase 2B trial results of AOD9604 (METAOD006)](https://data-api.marketindex.com.au/api/v1/announcements/XASX:PNV:XX270709/pdf) (rct, n=536, 2007): 24 weeks of oral AOD9604 produced no meaningful weight loss over placebo and the obesity programme was dropped.

## Sources

- [UniProt P01241: human growth hormone (residue 176 is phenylalanine)](https://www.uniprot.org/uniprotkb/P01241/entry)
- [WADA Prohibited List 2026 (S2.2.3: growth hormone fragments, e.g. AOD-9604 and hGH 176-191)](https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf)
- [Glow Peptides: AOD-9604 and the 176-191 name (vendors ship the Tyr sequence under both names)](https://glowpeptides.com/blog/aod-9604-hgh-fragment-176-191)
- [Wu & Ng 1993: hGH 177-191 antilipogenic, not lipolytic](https://pubmed.ncbi.nlm.nih.gov/8358331/)