Sialorphin TFA is an inhibitor of neutral endopeptidase (NEP) and aminopeptidase N (APN), which is responsive to androgen signaling. It inhibits the degradation of endogenous opioid peptides, interacting with μ-, δ-, and κ-opioid receptors. Sialorphin TFA modulates the ERK/mTOR signaling pathway by inducing cell cycle arrest, enhancing ERK1/2 activity, and reducing phosphorylation levels of mTOR, 4E-BP1, and p70S6K, thereby exhibiting antiproliferative activity against colorectal cancer, glioma, and prostate cancer cells without cytotoxicity. Additionally, it possesses anti-nociceptive properties, regulates sexual behavior, relaxes penile corpus cavernosum smooth muscle, and alleviates experimental colitis. Moreover, Sialorphin TFA serves as a copper (II) ion-binding ligand and has been utilized in mechanistic studies related to cancer, pain management, and inflammatory bowel disease.