What the research shows
Researchers compared six synthetic fragments from the end of human growth hormone in rats. The 176–191 fragment was among those associated with a brief rise in blood glucose and a more prolonged rise in insulin. Two shorter fragments were inactive in those tests. The results narrow down which residues mattered in these rat tests. A body-composition claim in humans would require a clinical study measuring fat mass. Comparison of six defined growth hormone fragments in rats.
FDA’s description of AOD-9604 specifies a tyrosine attached to the 177–191 segment. That detail matters when matching a paper about AOD-9604 to a native-sequence fragment. FDA description of the AOD-9604 structure.
Documented formats
The rat experiment used synthetic peptides of defined lengths. A paper about a modified terminal sequence or intact recombinant growth hormone describes a different material.
Testing and purity
Check the first residue, terminal groups, and bonding between the two cysteines. Identical residue counts can conceal differences in sequence or structure.
How to read a batch reportQuestions about HGH Fragment 176–191
Why specify both 176 and 191?
The numbers locate the first and last residues of the fragment. Shortening the sequence changed the observed response in the rat experiment.
Does a temporary glucose change demonstrate fat loss?
Glucose and insulin were measured in this experiment. Changes in fat mass require direct measurements over time.