Cinnamon

Genus Cinnamomum

One tree gives two completely different oils, and a second species gives a third. Bark oil is mostly cinnamaldehyde and smells like cinnamon should, sweet and warm. Leaf oil from the same tree is mostly eugenol and smells of cloves instead. Cassia is a different species, also cinnamaldehyde, but harsher and cheaper, and it is what most food flavouring uses. All three are among the strongest antibacterial oils in lab tests, and all three burn and sensitise skin, so they need heavy dilution.^[1]^[2]

Cinnamon Bark

Cinnamomum verum

Also Known As: Ceylon Cinnamon Bark, True Cinnamon Bark, Sri Lanka Cinnamon, Cinnamomum zeylanicum
Family: Spice
Perfumery Note: Middle
Intensity: Very Strong
Extraction: Steam Distillation
Plant Parts: Bark
Origins: Sri Lanka, Madagascar, India
Effect: Romance & Mood, Energy & Uplifting, Respiratory Support
Aroma: Spicy, Sweet, Warm, Rich
Applications: Diffusing & Inhalation, Cooking & Flavouring, Household & Cleaning
Price: $$$$Harvesting true cinnamon bark from Cinnamomum verum requires skilled hand-peeling of thin inner bark in Sri Lanka and Madagascar; the labour-intensive process and lower oil yield make bark oil significantly more expensive than leaf oil

Cinnamon bark oil is the real thing, two thirds to four fifths cinnamaldehyde. That is what makes it smell sweet and rounded where cassia smells flat and hot. In lab tests it tore open bacterial cell walls and spilled their contents, including in strains of E. coli that resist several drugs.^[3] It also mops up the unstable molecules that damage cells.^[4] Cinnamaldehyde is a known skin sensitiser, so keep it under half a percent in anything left on skin, and patch test first.^[5]

Cinnamon Leaf

Cinnamomum verum

Also Known As: Ceylon Cinnamon Leaf, True Cinnamon Leaf, Cinnamomum zeylanicum
Family: Spice
Perfumery Note: Middle
Intensity: Strong
Extraction: Steam Distillation
Plant Parts: Leaves
Origins: Sri Lanka, India, Madagascar
Effect: Sleep & Relaxation, Respiratory Support
Aroma: Spicy, Clove-like, Warm, Less Sweet than Bark
Applications: Diffusing & Inhalation, Cooking & Flavouring, Household & Cleaning
Price: $$$$Leaves are easily steam-distilled alongside pruning waste from cinnamon trees; the high leaf yield and minimal processing effort make leaf oil much cheaper than bark oil from the same tree

Cinnamon leaf oil comes from the same tree as bark oil but smells of cloves, not cinnamon. The reason is eugenol, which makes up most of it, where the bark runs on cinnamaldehyde. It is gentler on skin than bark oil, though it still sensitises and still needs diluting.^[5] In lab tests it broke up the protective films that Pseudomonas, Staphylococcus and Klebsiella build on surfaces.^[6] It did the same to Candida films, at strengths you could actually use in a skin preparation.^[7]

Cassia

Cinnamomum cassia

Also Known As: Chinese Cinnamon, Bastard Cinnamon, Cassia Cinnamon, Cinnamomum aromaticum
Family: Spice
Perfumery Note: Middle
Intensity: Very Strong
Extraction: Steam Distillation
Plant Parts: Bark
Origins: China, Vietnam, Indonesia
Effect: Romance & Mood, Energy & Uplifting, Respiratory Support
Aroma: Spicy, Warm, Harsh, Less Complex than Ceylon
Applications: Diffusing & Inhalation, Cooking & Flavouring, Household & Cleaning
Price: $$$$Often called "Chinese Cinnamon," it is cheaper and more abundant than true cinnamon

Cassia is what most of the world actually tastes when it tastes cinnamon. It is even higher in cinnamaldehyde than true cinnamon but lacks the sweet esters, so it lands hot and flat. In lab tests it held back bacteria, yeasts and moulds at very low concentrations.^[2] Paired with an antibiotic it worked against Klebsiella strains that shrug off almost everything.^[8] Like all cinnamon oils it sensitises skin and needs heavy dilution.^[5]

Essential Nose

Cinnamon

Cinnamon Bark

Cinnamon Leaf

Cassia

References