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Cortisol across conditions

Cortisol appears in 4 entries of the OSMF biomarker atlas, covering Gulf War Illness, Long COVID, ME/CFS, Major Depressive Disorder. Across those entries it is elevated in 1, mixed in 3. Because the same marker shifts in several unrelated conditions, it is best understood as a signal of shared biology such as inflammation, vascular or metabolic stress rather than as a condition-specific test. Each row below links to a page with the comparison group, associated symptoms, test details and primary citation.

Gulf War IllnessLong COVIDME/CFSMajor Depressive Disorder

Where Cortisol is reported

Also listed as: Cortisol (diurnal rhythm); Cortisol (diurnal); Glucocorticoid; HPA axis hormone

ConditionDirectionCompared againstAssociated symptomsSource
Gulf War Illness↕ inconsistenthealthy Gulf War veteran controlsFatigue, stress responseGean et al. 2021
Long COVID↕ inconsistenthealthy controlsHPA axis dysregulationBaalbaki et al. 2025
Major Depressive Disorder↑ elevatedMDD patients vs healthy controls (HPA axis dysregulation)—Nobis et al. 2020
ME/CFS↕ inconsistenthealthy controlsFlattened rhythm, fatigueMaksoud et al. 2023

Frequently asked questions

In which conditions is Cortisol altered?

In the OSMF atlas Cortisol is reported in Gulf War Illness, Long COVID, ME/CFS, Major Depressive Disorder. It is elevated in 1, mixed in 3 across 4 entries.

Does Cortisol point to one specific diagnosis?

No. Because Cortisol changes in several conditions (Gulf War Illness, Long COVID, ME/CFS, Major Depressive Disorder), an abnormal result cannot identify which condition, if any, is present. It must be interpreted with symptoms, history and other tests.

What is the LOINC code for Cortisol?

Entries in this atlas use LOINC 2143-6. LOINC codes identify the laboratory observation so results can be compared across systems.

Is one abnormal Cortisol result diagnostic?

No single biomarker result is diagnostic of any of these conditions. Findings reflect group averages from published cohorts with substantial overlap between patients and controls.

Cite this page

Open Source Medicine Foundation. (2026). Cortisol across conditions: biomarker evidence. OSMF Research Tracker. Retrieved October 7, 2026, from https://research.opensourcemed.info/biomarkers/markers/cortisol.html
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Last reviewed: 2026-07-03 · Browse: Biomarker Index · All marker pages · Biomarker Atlas

Disclaimer: Educational synthesis of peer-reviewed research; not medical advice. Findings are group-level and vary with study design. Discuss any result with a qualified clinician.