HGH 176-191 is a synthetic peptide, meaning it is a man-made sequence of amino acids. It is a modified segment of the natural human growth hormone (HGH) molecule.
 
To understand it:
The full HGH molecule is a large protein made of 191 amino acids.
This fragment is, as the name states, a small piece of that chain, specifically the segment from amino acid 176 to amino acid 191 (the very end of the HGH molecule).
 
Researchers discovered that this particular fragment was responsible for a significant portion of HGH's fat-burning (lipolytic) effects, but crucially, it appears to lack the other, more dangerous effects of full-length HGH.
 
How Does It Work? (The Proposed Mechanism)
Its primary and most well-known proposed mechanism is targeted fat loss. It works by mimicking the way natural HGH stimulates fat cells (adipocytes).
 
Stimulates Lipolysis: It binds to receptors on fat cells, particularly those in the stubborn areas like the abdomen, love handles, and thighs. This binding triggers an enzyme called hormone-sensitive lipase (HSL), which breaks down stored triglycerides into free fatty acids, releasing them into the bloodstream to be used for energy.
Inhibits Lipogenesis: At the same time, it is believed to block the body's ability to store new fat (a process called lipogenesis). It may do this by reducing the activity of an enzyme called lipoprotein lipase (LPL), which is responsible for taking fatty acids out of the bloodstream and storing them in fat cells.