PAL-GHK is a signal peptide  that sends a signal to the body and instructs it to perform an action. In this case, to increase collagen synthesis. Also known as palmitoyl tripeptide-1, or sometimes as palmitoyl oligopeptide, this short, three amino acid peptide  is often referred to as an ‘anti ageing’ peptide due to its biological effects.
PAL-GHK has been shown to boost collagen production in the body , as well as prevent the breakdown of collagen which can often happen with exposure to UVA light . Collagen is a natural protein that comes from the Greek word for ‘glue’ ; it provides the skin with elasticity and flexibility to minimise fine lines and wrinkles.
For this reason, PAL-GHK is often used in cosmetics. It is one of the most widely used peptides in anti-ageing products , and is an in-demand alternative to collagen-containing products as collagen molecules are too large to be absorbed topically .
However, PAL-GHK is also of interest to researchers looking at muscle health and strength. Collagen is an important element that makes up the extracellular framework of skeletal muscle and ligaments, and plays a significant role in muscle function. As the body produces 1% less collagen per year from age 20 , identifying ways to retain strength during the natural ageing process is an urgent area of research focus.
Studies have found that collagen peptides can increase body mass, fat-free mass, and strength  as well as reducing muscle soreness following bouts of exercise . https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7662462/  https://journals.sagepub.com/doi/10.1177/1091581818807863  https://www.mdpi.com/2079-9284/4/2/16/pdf  https://www.mdpi.com/2079-9284/7/4/91/htm  https://en.wiktionary.org/wiki/collagen  https://www.mdpi.com/2079-9284/7/4/91/htm  https://www.medicalnewstoday.com/articles/262881  https://www.scientificamerican.com/article/why-does-skin-wrinkle-wit/  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6566884/  https://link.springer.com/article/10.1007/s00726-019-02706-5