Sweet orange oil, cold-pressed from the ripe peel of Citrus sinensis, consists almost entirely of limonene (90-95%), giving it a bright, clean citrus sweetness that is softer and rounder than bitter orange. Limonene modulates monoamine neurotransmitter pathways; animal studies demonstrate that inhalation restores depression-induced behavioural changes and reduces HPA-axis hyperactivity.^[1] In a controlled human study, volunteers exposed to sweet orange aroma before an anxiogenic procedure showed no significant rise in state anxiety, subjective tension, or heart rate, providing direct clinical support for its traditional use as a calming aromatic.^[2]