AOD-9604 vs HGH Fragment 176-191

The Dose Guy’s verdict

Oct 27, 2026
3 sources

Neither. These are the same fat-burning tail of growth hormone sold under two names: AOD-9604 is the version that went into human obesity trials and never published a result, and HGH fragment 176-191 is the original that never got that far. If you are going to run one regardless, run AOD-9604: the silence in people is the same for both because it is the same stretch, so the tiebreak is a rat chapter the fragment lacks and one pin a day instead of two. For actual fat loss, the incretins have the human trials both of these lack.

Which would I take?Neither. Same tail, same dead end.

How they differ

The difference that matters is the paper trail, not the molecule. Both are short peptides cut from the end of human growth hormone, the stretch that was supposed to carry its fat-mobilizing effect without the growth signaling or the blood-sugar hit. AOD-9604 is that same stretch, one amino acid shorter and capped with a tyrosine, built as a drug candidate, and it went the whole way through early development: rodent studies, then phase 2 human trials for obesity, then silence and an abandoned program. The fragment never had a program. Its only published paper used it to steer a chemotherapy nanoparticle at breast-cancer cells.

In practice they feel the same, which for most people means very little. The forum stories are one story with two labels on the vial: a pin first thing on an empty stomach, and some fat loss that lines up suspiciously well with the diet started the same week. The rhythm is the only split you would notice. AOD-9604 runs as one morning pin, the fragment as two a day around fasting and training, so the fragment costs twice the needles for the same unproven idea.

If the scale is the goal, the money goes to tirzepatide or retatrutide, which delivered in people what both of these were supposed to. If the appeal was growth hormone without the growth, know that neither raises IGF-1 or does the recovery and sleep work a secretagogue does, so neither is a stand-in for GH.

What the research shows

No human trials. Zero. Everything below is animal or in-vitro work. Read it as “interesting,” not “evidence it works in you.”

AOD-9604 has a rat chapter and a dead clinical program; the fragment has a dish:

No head-to-head study of AOD-9604 against HGH fragment 176-191 exists, and neither has published randomized human efficacy results for fat loss.as of Aug 2026

In obese Zucker rats, oral AOD-9604 at 500 micrograms per kg daily for 19 days reduced weight gain by more than 50%, 15.8 g versus 35.6 g in controls.Horm Res 2000 · rat study

By February 2002, AOD-9604 was in phase 2a trials as a potential obesity treatment.2004 · development review

The fragment’s only published study used it as a targeting ligand on doxorubicin nanoparticles aimed at MCF-7 breast-cancer cells. It says nothing about fat loss.DDDT 2022 · in silico + cell line

No animal weight-loss study of HGH fragment 176-191 exists.as of Aug 2026

The best evidence on this page is a rat result, and it belongs to AOD-9604, the one whose human trials then went quiet.

How people run them

I am not writing a protocol for either, and the reason is the same for both: nobody published a human dose that did anything. For the record, the vendor market runs AOD-9604 at 250 to 300 mcg sub-q once a day, fasted, for 8 to 12 weeks, and the fragment at 250 to 500 mcg twice a day, fasted and around training. Those numbers are forum lore, not trial doses.

Switching between them changes nothing that matters. It is the same stretch of growth hormone, so if one did nothing for you over two months, the other will not rescue it. Stacking them is paying twice for one idea.

If you run one anyway, run AOD-9604, keep it to 8 weeks, and judge it by the scale and the tape measure, not by how a fasted morning feels. If nothing has moved by then, nothing is coming.

Side effects, side by side

Neither has a published human safety study, so this is user reports and an absence:

anecdotalInjection-site redness and itch on both, more of it on the fragment because it means twice the pins.

anecdotalLight-headedness when pinned fasted, reported mostly on the fragment around training. A small meal beforehand fixes it.

monitorBlood sugar deserves a glance on anything cut from growth hormone. AOD-9604 did not raise it in the rodent work; the fragment has no data either way.

unknownNo human safety data for either. Whatever stopped AOD-9604’s trials, efficacy or safety, was never published, and the fragment was never tested in a person at all.