cortisol

This term refers to the primary stress hormone of the human body, often associated with the fight-or-flight response. It carries a clinical and biological connotation, typically appearing in medical discussions regarding endocrine health, chronic stress, or metabolic regulation. As a chemical substance and hormone, it is an uncountable noun. It does not have a plural form in standard usage; instead, quantities are measured using terms like levels, concentrations, or doses.