S6K-18 is a selective inhibitor of p70 S6 kinase (S6K1), a key component in the mTOR signaling pathway. It is primarily used in research settings to study cellular processes such as protein synthesis, cell growth, and proliferation. By inhibiting S6K1, S6K-18 helps elucidate the role of the mTOR pathway in cancer, metabolic diseases, and aging. It has been utilized in preclinical studies to assess tumor growth suppression, particularly in cancers where mTOR signaling is hyperactive. Additionally, S6K-18 serves as a tool compound for investigating insulin resistance and metabolic regulation, offering insights into potential therapeutic strategies for diabetes and obesity-related conditions. Its selectivity makes it valuable for dissecting downstream effects of mTOR without directly inhibiting mTOR itself.