Peptides are tiny protein messengers that help cells talk by binding to...

https://future-wiki.win/index.php/GLP-1_Signaling_Explained_Without_the_Hype

Peptides are tiny protein messengers that help cells talk by binding to specific receptors. Researchers use peptides to study how receptors work, test which peptides bind best (selectivity), and observe the chain of signals triggered inside cells