hormone

1. (physiology) Any substance produced by one tissue and conveyed by the bloodstream to another to effect physiological activity.Examples: "Interfemale dominance may be facilitated by female sex hormones as well as adrenal testosterone..."; "Hormones are the bicycle couriers of the body, delivering chemical messages all around the teeming metropolis that is you."; "The text recounts a 2011 experiment: Researchers tested 136 healthy young men’s testosterone levels, asked them about their political party affiliations, then gave them either a placebo or ten grams of AndroGel one percent, a high-end dose of a common form of testosterone often used in hormone replacement therapies. […] Alogaily and the paper’s co-authors argued that this is “evidence that neuro-active hormones affect political preferences”."

2. (pharmacology) A synthetic compound with the same activity.Examples: "Tumours of the adrenal cortex which secreted feminizing hormones […]"; "Gender-affirming hormone therapy may involve testosterone for trans people assigned female at birth (AFAB) and estradiol and anti-androgens for trans people AMAB."

3. (pharmacology) A synthetic compound with the same activity.Examples: "I'm going to be going to slightly higher doses of hormones soon."colloquialplural-normally

4. (botany) Any similar substance in plants.