Cleare, A J, O'Keane, V, Miell, J · Clinical endocrinology · 2001 · DOI
This study looked at leptin, a hormone that affects appetite and weight, in people with ME/CFS. Researchers compared leptin levels in ME/CFS patients with healthy controls, then gave some patients a low dose of hydrocortisone (a steroid) to see if it changed leptin levels. They found that leptin levels were similar between patients and healthy people at baseline, but hydrocortisone increased leptin levels in ME/CFS patients, especially in those who felt better with the treatment.
This study provides insight into potential neuroendocrine dysregulation in ME/CFS and explores whether low-dose hydrocortisone therapy works through glucocorticoid pathways. The association between leptin response and clinical improvement may help identify which patients are likely to benefit from hydrocortisone, potentially enabling more personalized treatment approaches.
This study does not prove that leptin dysfunction causes ME/CFS, as baseline leptin levels were similar in patients and controls. It also does not establish that hydrocortisone is an effective therapy for all ME/CFS patients—only that it causes biochemical changes in some individuals. Correlation between leptin rise and clinical response does not prove causation; both may reflect a third underlying factor such as improved glucocorticoid receptor function.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Cleare, A J, O'Keane, V, & Miell, J (2001). Plasma leptin in chronic fatigue syndrome and a placebo-controlled study of the effects of low-dose hydrocortisone on leptin secretion.. Clinical endocrinology. https://doi.org/10.1046/j.1365-2265.2001.01341.x
BibTeX
@article{mecfsatlas-cleare-2001-plasma-leptin,
author = {Cleare, A J and O'Keane, V and Miell, J},
title = {Plasma leptin in chronic fatigue syndrome and a placebo-controlled study of the effects of low-dose hydrocortisone on leptin secretion.},
journal = {Clinical endocrinology},
year = {2001},
doi = {10.1046/j.1365-2265.2001.01341.x},
note = {PubMed: 11453960},
url = {https://www.mecfsatlas.com/evidence/cleare-2001-plasma-leptin},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/cleare-2001-plasma-leptin
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