Histamine load
Four receptors, four different jobs — H1 in allergy, H2 in gastric acid, H3 in the brain as a wakefulness signal, H4 in immune cells. That is why an antihistamine causes drowsiness and why blocking gastric acid is a different drug entirely. Diamine oxidase clears dietary histamine in the gut; its capacity varies between people.
In depth
Made from histidine, released by mast cells, and also a neurotransmitter and gastric acid signal.
What drives it
Calms histamine response increases it.
Mast cell degranulation is the principal acute source. Carried by the intermediary-metabolism, micronutrient and clinical reviews. doi 10.3390/nu18132141 · PMC9967593
Gut barrier reduces it.
Diamine oxidase clears dietary histamine in the gut; capacity varies between people. Carried by the intermediary-metabolism, micronutrient and clinical reviews. doi 10.3390/nu18132141 · PMC9967593
What it drives
It increases Eases allergy load.
H1-mediated bronchial and nasal response. Carried by the intermediary-metabolism, micronutrient and clinical reviews. doi 10.3390/nu18132141 · PMC9967593
It increases Clears blocked nose & sinuses.
Same mechanism in the upper airway. Carried by the intermediary-metabolism, micronutrient and clinical reviews. doi 10.3390/nu18132141 · PMC9967593
It increases Calm skin barrier.
Pruritus and cutaneous flare. Carried by the intermediary-metabolism, micronutrient and clinical reviews. doi 10.3390/nu18132141 · PMC9967593
It reduces Digestion.
H2-mediated gastric acid secretion. Carried by the intermediary-metabolism, micronutrient and clinical reviews. doi 10.3390/nu18132141 · PMC9967593
It reduces Sleep.
H3 in the brain is a wakefulness signal - which is why an antihistamine causes drowsiness and blocking gastric acid is a different drug entirely. Carried by the intermediary-metabolism, micronutrient and clinical reviews (PMC9967593; doi 10.3390/nu18132141; PMC12673670; doi 10.1016/j.molmet.2023.101755). Verbatim: “Administration of histamine or H1 receptor agonists induced wakefulness, whereas administration of H1 receptor antagonists promoted sleep”. doi 10.3390/nu18132141 · PMC9967593
Blends that modulate it
Each blend page names this pathway and carries the study behind its claim.
See it on the map
Open the causal map to follow this pathway upstream and downstream, arrow by arrow, each with its study.