Comparison

HGH Fragment 176-191 vs Mazdutide

Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research

HGH Fragment 176-191

Also: Frag 176-191, HGH Frag

Clinical Trials

HGH Fragment 176-191 is exactly what it sounds like: a short tail-end piece of the human growth hormone molecule, amino acids 176 through 191. The idea was to keep the fat-burning part of growth hormone while ditching the parts that raise blood sugar and IGF-1. The optimized drug version, AOD-9604, actually went through real human trials for obesity, and the blunt result is that it was very safe but did not produce meaningful weight loss.

Weight LossHuman Trials
Mazdutide

Also: IBI362, LY3305677

Clinical Trials

Mazdutide is a GLP-1 and glucagon dual agonist, which puts it between semaglutide (GLP-1 only) and retatrutide (GLP-1, GIP and glucagon). It is built on oxyntomodulin, a natural gut hormone that hits both receptors, rather than on a GLP-1 backbone. It is furthest along in China, where it is approved for both weight management and type 2 diabetes. Western approval has not happened.

Weight LossHuman Trials

Key Comparison Insights

  • Both peptides belong to the Weight Loss category, suggesting similar primary applications.

Detailed Comparison

AttributeHGH Fragment 176-191Mazdutide
CategoryWeight LossWeight Loss
FDA StatusNot FDA ApprovedNot FDA Approved
Clinical Status
Pre
I
II
III
IV
FDA
Pre
I
II
III
IV
FDA
Mechanism of ActionThis fragment is the C-terminal portion of growth hormone, the segment researchers identified as carrying its lipolytic (fat-breakdown) activity. In lab and animal work it stimulates fat cells to release and burn fat, increasing glycerol output and fat oxidation, apparently without binding the growth hormone receptor itself. That is the selling point: because it does not act on the GH receptor, it does not raise IGF-1, does not promote tissue growth, and does not impair glucose handling the way full growth hormone can. Some research points to involvement of beta-3 adrenergic signaling in fat tissue, though the exact human mechanism is not fully nailed down.Two receptors, two jobs. The GLP-1 arm does the familiar work: it suppresses appetite, slows gastric emptying and improves glucose-dependent insulin release. The glucagon arm is the interesting half, because glucagon is normally thought of as the hormone that raises blood sugar. At these doses the intent is to exploit glucagon's other effects, increasing energy expenditure and pushing the liver to burn fat, while the GLP-1 arm keeps blood glucose in check and cancels out glucagon's hyperglycemic tendency. That balance is the whole design: glucagon supplies extra fat burning that GLP-1 alone cannot, and GLP-1 supplies the safety margin that makes adding glucagon viable. Reported reductions in liver fat are consistent with the glucagon component doing what it is meant to.
Common Dosing
250-500 mcg daily
1-2x daily, fasted
4-6 mg weekly
Once weekly
AdministrationSubcutaneous injection on empty stomachSubcutaneous injection, once weekly
Typical Duration8-12 weeksOngoing weekly use in trials, typically assessed at 24 to 48 weeks
Best Time to TakeBefore bed or morning (fasted)Same day each week, morning preferred
Possible Side Effects
May vary by individual
  • Generally well-tolerated
  • Injection site reactions
  • Mild headache
  • Nausea
  • Does NOT cause typical HGH side effects
  • +2 more
  • Nausea, worst during dose escalation
  • Vomiting
  • Diarrhea
  • Decreased appetite (the intended effect, but can be excessive)
  • Injection site reactions
  • +2 more
Research SummaryThe animal data looked promising and the human data deflated it, which is the whole story here. In obese mice (International Journal of Obesity, 2001), both growth hormone and AOD-9604 reduced body-weight gain and increased fat oxidation, without the blood-sugar problems of full GH. A small 12-week phase 2 human study generated the famous early headline, with the 1 mg group losing about 2.8 kg versus 0.8 kg on placebo. But the larger, better-powered phase 2b trial of roughly 500 obese adults over 24 weeks failed to show a significant weight-loss advantage over placebo, and the developer abandoned obesity development. What survived is the safety record: across about six trials and roughly 900 people, AOD-9604 was as well tolerated as placebo, with no IGF-1 rise and no glucose effects (Journal of Endocrinology and Metabolism, 2013). So it is safe and it does not work as a meaningful fat-loss drug in humans.The pivotal trial is GLORY-1, published in the New England Journal of Medicine in 2025: 610 Chinese adults with overweight or obesity over 48 weeks. Mean weight reduction was 11.0 percent at 4 mg and 14.0 percent at 6 mg, alongside improvements in liver fat, blood pressure and lipids. A 9 mg dose has since been studied in phase 2 (about 12.8 percent at 24 weeks) and is in phase 3. Tolerability followed the pattern of the whole class, dominated by dose-dependent nausea, vomiting and diarrhea during titration. One caveat matters when reading these numbers: GLORY-1 enrolled a population with a mean BMI of 31.1, against roughly 38 in the Western trials of semaglutide and tirzepatide, so the percentages are not directly comparable to SURMOUNT-1 or STEP-1 results. There is no completed Western phase 3 program, so neither the FDA nor the EMA has assessed it, and meaningful head-to-head data against tirzepatide or retatrutide does not exist.

Frequently Asked Questions: HGH Fragment 176-191 vs Mazdutide

What is the difference between HGH Fragment 176-191 and Mazdutide?

HGH Fragment 176-191 is a weight loss peptide that hgh fragment 176-191 is exactly what it sounds like: a short tail-end piece of the human growth hormone molecule, amino acids 176 through 191. the idea was to keep the fat-burning part of growth hormone while ditching the parts that raise blood sugar and igf-1. the optimized drug version, aod-9604, actually went through real human trials for obesity, and the blunt result is that it was very safe but did not produce meaningful weight loss. Mazdutide is a weight loss peptide that mazdutide is a glp-1 and glucagon dual agonist, which puts it between semaglutide (glp-1 only) and retatrutide (glp-1, gip and glucagon). it is built on oxyntomodulin, a natural gut hormone that hits both receptors, rather than on a glp-1 backbone. it is furthest along in china, where it is approved for both weight management and type 2 diabetes. western approval has not happened. The main differences lie in their mechanisms of action and clinical applications.

Which is better, HGH Fragment 176-191 or Mazdutide?

Neither is universally "better" - the choice depends on your specific goals. HGH Fragment 176-191 is typically used for weight loss purposes, while Mazdutide is used for weight loss. Always consult with a healthcare provider to determine which may be appropriate for your situation.

Can HGH Fragment 176-191 and Mazdutide be used together?

Some peptide protocols combine multiple compounds for synergistic effects. However, using HGH Fragment 176-191 and Mazdutide together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.

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