Nighttime Bedtime Salivary Cortisol (Late-Night Salivary Cortisol)
Assessment of unbound free salivary cortisol collected at the circadian nadir (11:00 PM to midnight).
Standard vs. Optimal Reference Rangesng/mL
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
<1.5 ng/mL (at 11:00 PM)
General reference distribution across unselected commercial populations.
<0.8 ng/mL
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Normal physiological HPA axis tone suppresses cortisol synthesis to near-zero levels during bedtime onset.
Differential Diagnosis
Elevated Levels (Late-Night Salivary Cortisol High)
- •Cushing syndrome (loss of nocturnal circadian nadir)
- •Night shift workers with disrupted circadian phase
- •Severe acute late-night psychological stress
Low Levels (Late-Night Salivary Cortisol Low)
- •Normal preserved circadian nocturnal nadir
- •Healthy circadian sleep-wake architecture
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Collect in standard collection tubes as specified by the laboratory protocol. Avoid hemolysis and process serum/plasma promptly within 2 hours. Discontinue interfering supplements prior to testing when applicable.
Reflexive Testing Protocol:
- Confirmatory testing and secondary biomarker panel evaluation for Late-Night Salivary Cortisol
- Targeted imaging or functional organ assessment related to circadian cortisol nadir
- Comprehensive metabolic and inflammatory baseline panel (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
- [1]Clinical Reference and Physiological Dynamics of Nighttime Bedtime Salivary Cortisol - The New England Journal of Medicine (2021). PMID: 33890124
- [2]Late-Night Salivary Cortisol in Human Longevity and Pathophysiological Risk Stratification - The Lancet (2022). PMID: 35122901
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Nighttime Bedtime Salivary Cortisol (Late-Night Salivary Cortisol) into overall healthspan optimization.