Spantide I TFA is primarily used in research settings as a potent antagonist of substance P, a neuropeptide involved in pain transmission and inflammation. It is widely applied in neuroscience and pharmacology studies to investigate neurokinin receptor functions, particularly the NK1 receptor. Due to its ability to block substance P activity, it serves as a tool compound in studying pain pathways, neurogenic inflammation, and potential treatments for conditions like chronic pain, migraine, and depression. It is also utilized in in vitro assays to evaluate receptor binding and signal transduction mechanisms. Its trifluoroacetate salt form enhances solubility and stability, making it suitable for cellular and molecular experiments.