Melatonin
Plain-English definitions of microbiome research vocabulary — the terms you'll see across articles, testing services, and probiotic claims.
A hormone primarily associated with sleep regulation, produced by the pineal gland and — in much larger quantities — by enterochromaffin cells in the gut. Gut-derived melatonin influences intestinal motility, inflammation, and epithelial barrier function, and its production is influenced by the microbiome.
Related terms
Enterochromaffin Cells
Specialised cells in the gut lining that produce approximately 95% of the body's serotonin. Their activity is directly influenced by the gut microbiome, making them a key link in the gut-brain axis.
Circadian Rhythm
The approximately 24-hour biological cycle that governs sleep-wake patterns, hormone release, and metabolism. The gut microbiome exhibits its own circadian fluctuations in composition and function, influenced by meal timing, light exposure, and host circadian clock genes.