At a glance
| Chemical family | An aromatic aldehyde (cinnamaldehyde); the dominant constituent of cinnamon bark oil. Closely linked to cinnamyl alcohol, with which it appears to share a reactive hapten |
| CAS number | 104-55-2 |
| Classification | Not IARC-classified (it does not appear in the IARC list — an absence of evaluation, not a safety finding). A potent contact allergen and a constituent of Fragrance Mix I; an EU-declared fragrance allergen |
| Where you encounter it | Cinnamon bark oil and cinnamon/spice scents; fragrance in perfumes, soaps, detergents and household products; a food flavouring; toothpastes and chewing gum |
| Sleep micro-environment relevance | Fragrance that survives laundering and sits against the skin all night; for the fragrance-allergic, a pillowcase is eight hours of warm, occluded contact with a potent allergen |
| Activated carbon capture | Not the main lever — the exposure that matters is skin contact with treated fabric, so fragrance-free laundry is the direct fix |
What it is
Cinnamal (cinnamaldehyde) is the aromatic aldehyde that gives cinnamon its characteristic smell and flavour, and the dominant constituent of cinnamon bark oil. It is used as a fragrance in perfumes, soaps, detergents and household products, and as a flavouring in food, toothpaste and chewing gum. Peer-reviewed — Buckley et al. 2006
Cinnamal is not IARC-classified. It does not appear in the IARC list of classified agents at all. Inferred — cinnamal does not appear in the IARC list of classified agents; that is an absence of evaluation, not a finding of safety So this page is not about cancer. It is about the hazard cinnamal genuinely has, which is skin sensitization, and on that measure it is one of the more potent fragrance allergens in routine use.
How it relates to the bedroom
The fragrance that survives the wash
Cinnamal's bedroom route is ordinary fragrance. It is used in soaps, detergents and household products, and laundry scent is engineered to persist on fabric, so it remains on washed bedding pressed against skin. Inferred — from cinnamal's documented use as a soap and detergent fragrance and the designed persistence of laundry scent; cinnamal specifically has not been measured on laundered bedding For most sleepers this is unremarkable. For someone sensitized to cinnamal, it is a nightly, warm, occluded dose to the face and neck.
One of the strongest fragrance allergens
Cinnamal is one of the eight constituents of Fragrance Mix I, the standard screening mix for fragrance allergy. In a series of 23,660 patients patch-tested to the European standard series, 7.7% reacted to Fragrance Mix I. Peer-reviewed — Buckley et al. 2006
Cinnamal is also unusually tightly coupled to its alcohol. Of 139 patients allergic to cinnamyl (cinnamic) alcohol, 87 — 63% — were also allergic to cinnamal, against 11.1% of cinnamyl-alcohol-negative patients. Peer-reviewed — Buckley et al. 2006 The authors read this as evidence that the two compounds generate a common reactive hapten in the skin: the alcohol is oxidized to the aldehyde, so sensitization to one tends to bring the other with it. Inferred — the shared-hapten interpretation is the authors' reading of the co-reaction data
Declared on EU labels
Cinnamal is one of the fragrance allergens the EU requires to be declared on cosmetic labels above set thresholds (0.001% leave-on, 0.01% rinse-off), under Commission Regulation (EU) 2023/1545, with full compliance from 31 July 2026. Regulatory — EU 2023/1545 For a diagnosed cinnamal allergy, that declaration is the practical avoidance tool.
What the research says
- Not IARC-classified. Cinnamal does not appear in the IARC list; this is an absence of evaluation, not a safety finding. Inferred
- A Fragrance Mix I constituent. 7.7% of 23,660 patch-tested patients reacted to Fragrance Mix I. Peer-reviewed — Buckley et al. 2006
- Tightly coupled to cinnamyl alcohol. 63% of cinnamyl-alcohol-allergic patients also reacted to cinnamal, versus 11.1% of the alcohol-negative. Peer-reviewed — Buckley et al. 2006
- Probably a shared hapten. The alcohol appears to oxidize to the aldehyde, so sensitization to one brings the other. Inferred — the authors' reading of the co-reaction data
- EU-declared allergen. Must be named on cosmetic labels above threshold. Regulatory — EU 2023/1545
What helps reduce it
Use fragrance-free detergent on bedding. For a cinnamal-allergic sleeper this is the single highest-yield change, because it removes a potent allergen from eight hours of occluded skin contact. Inferred
If you react to cinnamal, treat cinnamyl alcohol as suspect too. The two co-react in most patients. Peer-reviewed — Buckley et al. 2006
Read the EU allergen declarations. Cinnamal must be named above threshold. Regulatory — EU 2023/1545
What does NOT help
- Treating it as a cancer risk. Cinnamal is not IARC-classified; the documented hazard is contact allergy. Inferred
- Cutting cinnamon out of your diet. The documented problem is skin contact with fragrance, not eating cinnamon. Inferred
Open research questions
- How much cinnamal actually persists on laundered bedding from detergent fragrance — not measured. Speculation
- Whether a warm, occluded pillowcase raises elicitation thresholds for cinnamal compared with ordinary daytime skin contact. Speculation
Citations
- Buckley DA, Basketter DA, Smith Pease CK, Rycroft RJG, White IR, McFadden JP (2006). Simultaneous sensitivity to fragrances. British Journal of Dermatology 154(5):885–888. Of 23,660 patients patch-tested to the European standard series, 1,811 (7.7%) reacted to Fragrance Mix I. Of 139 patients allergic to cinnamyl alcohol, 87 (63%) were also allergic to cinnamal, versus 11.1% of cinnamyl-alcohol-negative patients, supporting a common reactive hapten. PMID 16634891. doi.org/10.1111/j.1365-2133.2006.07170.x Peer-reviewed
- Commission Regulation (EU) 2023/1545 amending Regulation (EC) No 1223/2009 as regards labelling of fragrance allergens (Annex III). Cinnamal must be declared on cosmetic labels above 0.001% (leave-on) / 0.01% (rinse-off); compliance from 31 July 2026. EUR-Lex Regulatory
Frequently asked questions
What is cinnamal?
Cinnamal, also called cinnamaldehyde, is the compound that gives cinnamon its smell and taste, and the dominant constituent of cinnamon bark oil. It is used as a fragrance in perfumes, soaps, detergents and household products, and as a flavouring. In the bedroom it reaches you as fragrance that persists on laundered bedding and from spice-scented personal-care products.
Is cinnamal a carcinogen?
Cinnamal does not appear in the IARC list of classified agents, so it has no IARC carcinogenicity classification. That is not the same as a clean bill of health — it means IARC has not evaluated it. Its well-documented and clinically important hazard is a different one: it is among the most potent contact allergens in the standard fragrance screening panel.
How allergenic is it?
Very. Cinnamal is one of the eight constituents of Fragrance Mix I; 7.7% of 23,660 patients patch-tested to the European standard series reacted to that mix. Cinnamal is also tightly linked to cinnamyl (cinnamic) alcohol: 63% of patients allergic to cinnamic alcohol also reacted to cinnamal, consistent with the two generating a common reactive hapten in the skin.
Should I be worried about it?
If you have no fragrance allergy, cinnamal in a detergent is not a cancer concern and cinnamon in food is not the issue. If you do have fragrance-allergic dermatitis, cinnamal is one of the likeliest culprits, and a fragranced pillowcase gives it eight hours of warm, occluded skin contact every night. Fragrance-free bedding laundry is the direct fix, and the EU now requires cinnamal to be named on cosmetic labels.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-07-14. If you find a factual error, contact us.