Cortisol

hormone · nervous · cardiovascular · endocrine · immune-hematologic · Oral · IV · Transdermal

Cortisol, a hormone. Principal human glucocorticoid. Synthesised from cholesterol in the zona fasciculata under HPA-axis control (CRH → ACTH →… Oral half-life 1.7 h.

Principal human glucocorticoid. Synthesised from cholesterol in the zona fasciculata under HPA-axis control (CRH → ACTH → cortisol). Binds GR → nuclear translocation → transactivation (anti-inflammatory genes) and transrepression (NF-κB, AP-1). Diurnal peak 06:00–08:00, nadir 00:00. Negative feedback at hypothalamus + pituitary.

PK: Derendorf 1991 (PMID:2050835), 20 mg IV/PO crossover in dexamethasone-suppressed subjects, verbatim "half-life of 1.7 hr. The volume of distribution was 34 L. Oral bioavailability averaged 96%", Tmax 1 h; ka not stated. Johnson 2018 (PMID:29795974) corroborates F "1.00 (0.89-1.14)". Half-life is dose-conditional through CBG saturation — 1.2 h at 5 mg rising to 1.7 h at 40 mg (Toothaker 1982, PMID:7143223); the 20 mg value is stored. IM route removed 2026-09-06: no human abstract states an IM absorption parameter. hydrocortisone is the same molecule and was merged into this record.

Pharmacokinetics

• Oral — t½ 1.7 h · F 96% · Vd 34 L
• IV — t½ 1.7 h · F 100% · Vd 34 L

Related compounds

• Ashwagandha — caution

Sources: PMID:15634032, PMID:8282004, PMID:2050835, PMID:29795974, PMID:7143223