HGH Fragment 176-191

HGH Fragment 176-191 cuts only the C-terminal tail out of the 191-residue growth hormone. The idea behind it: remove the sequences that switch on the growth axis and the metabolic effect remains. Its close relative AOD-9604 (sequence 177-191) supplies most of the data.

Animal findings:

• Orally given AOD-9401 curbed weight gain in obese mice; in adipose tissue lipolysis went up and lipogenesis down, something also seen in isolated fat tissue from humans (2000).
• Over 14 days both hGH and the C-terminal fragment AOD9604 lowered weight gain and raised fat oxidation in obese mice; the hGH receptor stayed unoccupied by the fragment, and there was neither hyperglycemia nor cell proliferation (2001).
• Both agents increased expression of the beta-3 adrenergic receptor; in knockout mice lacking that receptor the weight effect disappeared, so the receptor is part of the mechanism (2001).
• In obese Zucker rats a daily oral dose for 19 days cut weight gain by more than half, and insulin sensitivity did not suffer (2000).

Mechanistically the fragment is linked to higher activity of hormone-sensitive lipase and stronger beta-3 stimulation, in other words fat mobilization. As a small peptide of 16 amino acids it is cleared quickly; the half-life is short. For studies that want to look at lipolysis in isolation from growth and glucose metabolism, the fragment is therefore the leaner tool compared with the whole hormone.

Because the fragment lacks the growth- and insulin-active segments, its profile is gentler than the complete hormone's. The pronounced fluid retention or carpal tunnel type complaints of the GH literature are largely absent here.

• Injection site: redness, pressure or brief irritation are the most common findings.
• Isolated reports mention short tiredness or a mild feeling of warmth right after dosing.
• Rapid clearance limits the duration of action but does not change the mild picture.
• The evidence consists almost entirely of animal models and short anecdotal experience; robust long-term human studies do not exist.

This summary is no substitute for medical advice.

• Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolism - oral AOD-9401 in obese mice and on human fat tissue.
• Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment - 14-day comparison of hGH and fragment in obese mice.
• Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone - 19 days of oral dosing in obese Zucker rats.