Ho Leaf Oil
Ho leaf oil
Genuinely relevant for some people, or depends on dose and pH.
Also written as: Ho Wood Oil · Cinnamomum Camphora Leaf Oil · Shiu Oil · Cinnamomum Camphora Linalooliferum Oil
What it is
Ho leaf oil comes from the linalool chemotype of Cinnamomum camphora and is typically 80 to 95% linalool, with very little camphor. It became widely used as a replacement for endangered Brazilian rosewood, which has a similar profile. Because it is essentially a natural source of a single molecule, its behaviour on skin is close to that of linalool itself.
What it does well
A sustainable alternative to rosewood oil
It supplies a comparable soft floral-woody linalool note without pressure on threatened Aniba rosaeodora populations. This is an environmental rather than a skin benefit.
Strong evidence
Worth knowing
Effectively a concentrated dose of linalool
Since the oil is up to 95% linalool, it carries the same oxidation problem: air exposure produces hydroperoxides that are frequent contact allergens. Of 5773 consecutive Swedish dermatitis patients patch tested between 2013 and 2020, 7.0% reacted to oxidised linalool, more than reacted to oxidised limonene, and the rate rose significantly over the period.
Matters most toPeople with a known linalool hydroperoxide allergy.
Where the EU stands
No specific restriction
Ho leaf oil is not itself on the Annex III fragrance-allergen labelling list, which names Cinnamomum Cassia Leaf Oil (entry 348) and Cinnamomum Zeylanicum Bark Oil (entry 349) but not the linalool chemotype of Cinnamomum camphora. Its linalool content must be declared as Linalool, Annex III entry 84, above the usual thresholds.
Sources (2)
Every link goes to the original: a journal, a PubMed record or an EU document.
- [1]Contact allergy to oxidized linalool and oxidized limonene: Patch testing in consecutive patients with dermatitis
Contact Dermatitis · 2022 · doi:10.1111/cod.13980
Among 5773 consecutive dermatitis patients patch tested in Sweden between 2013 and 2020, 7.0% reacted to oxidised linalool and 5.1% to oxidised limonene, with significantly increasing trends over the period.
- [2]Air-oxidized linalool elicits eczema in allergic patients - a repeated open application test study
Contact Dermatitis · 2014 · doi:10.1111/cod.12163
In participants already allergic to oxidised linalool, creams containing as little as 0.3% oxidised linalool applied twice daily elicited eczema, showing that repeated exposure to low concentrations is enough to provoke allergic contact dermatitis in sensitised people.