Research

Hormonal

Exposure to light at night (LAN), even at dim levels (e.g., 5 lux), disrupts circadian clock gene expression in the suprachiasmatic nucleus (SCN) and peripheral tissues (e.g., liver), which alters metabolic function and contributes to obesity and metabolic disorders.

Minimize exposure to artificial light during your biological night. Even dim light (like from a phone or nightlight) can disrupt your internal clock and metabolism. Use blackout curtains, dim red lights if necessary, and avoid screens before sleep to support healthy hormone regulation and weight management.

GoodSupportsHIGH confidence
In this review, we propose that exposure to light at night alters metabolic function through disruption of the circadian system.
Laura K. Fonken et al. · Endocrine Reviews · 2014

Why this rating

The paper is a review citing multiple animal models and epidemiological studies, but lacks large-scale human interventional trials proving causality in humans.

Source

The Effects of Light at Night on Circadian Clocks and Metabolism

Laura K. Fonken et al. · Endocrine Reviews · 2014

DOI 10.1210/er.2013-1051

narrative_reviewCited 452×
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DOI resolved against Crossref · corpus check 2026-06-10

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