MelatoninvsReishi

Melatonin binds to G-protein-coupled MT1 and MT2 receptors, which are densely expressed in the suprachiasmatic nucleus (SCN) of the hypothalamus—the brain's master circadian pacemaker. MT1 activation couples to Gi/o proteins, inhibiting adenylyl cyclase and reducing cAMP, which suppresses SCN neuronal firing and promotes sleepiness. MT2 activation modulates cGMP signaling and phase-shifts the circadian rhythm (useful for jet lag and shift work). Melatonin also has direct antioxidant properties, scavenging hydroxyl and peroxyl radicals in mitochondria and upregulating antioxidant enzymes like glutathione peroxidase. It supports immune function through modulation of T-cell cytokine production and may act at MT3 (quinone reductase 2) binding sites. Low doses are often more effective because they mimic physiological nighttime levels.

Reishi's triterpenes (ganoderic acids A, C, D, H; ganoderenic acids) modulate the HPA axis by reducing CRH and ACTH release, lowering cortisol via glucocorticoid receptor feedback. Ganoderic acids have direct sedative effects through GABA-A receptor modulation (possibly allosteric at the benzodiazepine site) and 5-HT2A/2C serotonergic modulation. Beta-(1,3)-(1,6)-glucan polysaccharides bind Dectin-1 and complement receptor 3 (CR3) on macrophages, natural killer cells, and dendritic cells, activating NF-kB and MAPK signaling for immune modulation. Reishi inhibits histamine release from mast cells via Fc epsilon RI downregulation and stabilizes mast cell membranes (anti-allergic effect). Antioxidant properties involve upregulation of superoxide dismutase (SOD1/SOD2), catalase, and glutathione peroxidase. Ganoderic acids may also inhibit 5-alpha-reductase and ACE.