At a glance
| What this is | A small reactive dialdehyde (ethanedial) used as the leading formaldehyde-free durable-press / wrinkle-resist / "easy-care" crosslinking finish for cotton and cellulosic fabric |
| CAS number | 107-22-2 |
| Carcinogen status | Not classified by IARC — not a carcinogen on current evidence. (This is its advantage over the formaldehyde finishes it replaces.) |
| Other key hazards | EU harmonised classification: skin sensitiser (H317) and suspected mutagen (Muta. 2, H341); skin/eye/respiratory irritant. Mutagenic in vitro; negative in the in-vivo mouse micronucleus test |
| Where you encounter it | "Wrinkle-free," "non-iron," "easy-care" cotton and cotton-blend sheets, pillowcases and apparel that advertise being formaldehyde-free |
| Sleep micro-environment relevance | A reactive finish bound into bedding fabric; residual unbound finish can sensitise or irritate skin, especially before a first wash |
| Regulation | Durable-press rules target formaldehyde release (Japan Law 112, China GB 18401, OEKO-TEX); glyoxal's own hazards governed by chemical law (EU CLP) |
What it is
Cotton wrinkles because its cellulose chains slide and re-hydrogen-bond when the fabric is bent. Durable-press finishing stops that by chemically crosslinking the chains so they spring back. Glyoxal — a two-carbon dialdehyde — does this crosslinking with a metal-salt catalyst and is the principal formaldehyde-free durable-press agent. Peer-reviewed — Ke et al. 2021
It exists for one reason: to get away from formaldehyde. The dominant durable-press resin, DMDHEU, releases formaldehyde during wear and laundering, and formaldehyde is an IARC Group 1 carcinogen — so the field has spent decades moving to formaldehyde-free agents, of which glyoxal-based dialdehydes are a leading class. Peer-reviewed — Wang et al. 2023 Peer-reviewed — Welch 2008
How it relates to the bedroom
It is the "formaldehyde-free easy-care" finish on your sheets
If a sheet set is marketed as "wrinkle-free," "non-iron" or "easy-care" and "formaldehyde-free," a glyoxal-type dialdehyde finish is one of the most likely chemistries doing the work. Peer-reviewed — Welch 2008 That is the good news embedded in this page: the move from formaldehyde resins to glyoxal is a real reduction in a Group 1 carcinogen on a surface you breathe against and sweat into for a third of your life.
But "formaldehyde-free" is not "inert"
Glyoxal is a reactive aldehyde in its own right, and the EU's harmonised classification reflects that: it is a skin sensitiser (H317, may cause an allergic skin reaction) and a suspected mutagen (Muta. 2, H341), along with skin, eye and respiratory irritant classifications. Regulatory — EU CLP harmonised classification, glyoxal Crucially, the mutagenicity picture is mixed: glyoxal is mutagenic in laboratory (in vitro) assays but was negative in the in-vivo mouse micronucleus test, and it is not an IARC-classified carcinogen — so the honest framing is a reactive sensitiser of uncertain genotoxic significance, not a known carcinogen. Regulatory — EU CLP; in-vitro positive / in-vivo micronucleus negative
For bedding, the practical issue is the residual, unbound finish: a reactive dialdehyde in direct, sweaty, all-night skin contact is a plausible cause of irritation or allergic sensitisation in susceptible people, particularly on a new, unwashed sheet. Inferred — skin sensitisation/irritation from residual reactive finish follows from glyoxal's CLP skin-sensitiser classification and the bedding contact route
Keeping it in proportion
This is a "better, not perfect" story, and it should be read as one. Swapping formaldehyde for glyoxal removes a confirmed carcinogen and replaces it with a sensitiser whose worst-case genotoxicity did not show up in the live-animal test. Regulatory — EU CLP; IARC (glyoxal not classified) The cleanest option of all is simply un-finished bedding — sheets that wrinkle but carry no durable-press chemistry at all. Inferred — untreated fabric avoids both formaldehyde and glyoxal finishes
The regulatory picture — worldwide
The regulation here is mostly aimed at formaldehyde, and glyoxal is the industry's answer to it — so the two have to be read together.
Formaldehyde-release limits drive the switch. Japan's Law 112 effectively prohibits detectable free formaldehyde in textiles for infants and limits it in others; China's GB 18401 sets formaldehyde-release limits by use class; and the EU and many markets restrict formaldehyde in skin-contact textiles. These limits are what made formaldehyde durable-press resins commercially difficult and pushed mills toward glyoxal. Regulatory — Japan Act 112 on Household Products; China GB 18401 (formaldehyde limits for textiles)
Voluntary standards. OEKO-TEX Standard 100 sets strict formaldehyde limits (lowest for baby articles) and screens for harmful residues generally, so a certified "easy-care" sheet must clear the formaldehyde bar — again favouring glyoxal-type finishes. Industry — OEKO-TEX Standard 100 formaldehyde limit values
Glyoxal's own controls. Glyoxal itself is governed by general chemical law rather than textile-specific bans: the EU CLP harmonised classification (skin sensitiser; suspected mutagen) sets its handling and labelling, and it is registered under REACH. Regulatory — EU CLP Regulation (EC) 1272/2008; REACH registration
Where it is heading. Research is steadily moving past glyoxal toward polycarboxylic-acid crosslinkers (citric acid, BTCA) that are neither formaldehyde- nor aldehyde-based, signalling a regulatory and market drift toward finishes with cleaner toxicology than either formaldehyde or glyoxal. Peer-reviewed — Wang et al. 2023 (polycarboxylic-acid agents as leading next-generation crosslinkers)
What the research says
- The leading formaldehyde-free durable-press finish. Effective wrinkle-resist crosslinker for cotton/cellulosics. Peer-reviewed — Ke et al. 2021; Welch 2008
- Exists to replace formaldehyde resins. DMDHEU releases formaldehyde (Group 1 carcinogen) during use. Peer-reviewed — Wang et al. 2023
- Skin sensitiser + suspected mutagen. EU CLP: H317, Muta. 2 (H341). Regulatory — EU CLP
- Not an IARC carcinogen. In-vitro mutagenic but in-vivo micronucleus negative. Regulatory — EU CLP / IARC (not classified)
What helps reduce it
Wash new easy-care bedding before first use. Laundering removes residual unbound finish — the fraction most able to contact and sensitise skin. Inferred — washing removes unfixed reactive finish, standard for new treated textiles
Choose untreated bedding if you can tolerate wrinkles. Plain, un-finished cotton or linen carries neither formaldehyde nor glyoxal durable-press chemistry. Inferred — untreated fabric avoids durable-press finishes entirely
Prefer OEKO-TEX-certified "easy-care." If you want wrinkle resistance, certification at least guarantees the formaldehyde side is controlled. Industry — OEKO-TEX Standard 100
What does NOT help
- Assuming "formaldehyde-free" means hazard-free. Glyoxal is a sensitiser and suspected mutagen in its own right. Regulatory — EU CLP
- Air filtration. This is a finish bound in fabric and contacted through skin, not an airborne pollutant. Inferred
Open research questions
- How much residual glyoxal remains on finished bedding after manufacture and how a first wash changes it. Speculation
- The real-world skin-sensitisation rate from glyoxal-finished bedding versus formaldehyde-finished bedding. Speculation
- Whether polycarboxylic-acid finishes will displace both formaldehyde and glyoxal in mainstream easy-care bedding. Speculation
Citations
- Welch CM (2008). Formaldehyde-free durable-press finishes. Review of non-formaldehyde durable-press agents; need driven by formaldehyde being a probable human carcinogen; glyoxal and polycarboxylic acids leading candidates. Via Consensus. Reference record Peer-reviewed
- Ke G, et al. (2021). Anti-wrinkle finishing of Tencel fabric with glyoxal. J. Textile Inst. Glyoxal a formaldehyde-free anti-wrinkle finish; crosslinking confirmed by FTIR, increased wrinkle-recovery angle. Via Consensus. Reference record Peer-reviewed
- Wang J, et al. (2023). A review on the status of formaldehyde-free anti-wrinkle cross-linking agents for cotton fabrics. Ind. Crops Prod. DMDHEU releases formaldehyde during use; dialdehydes such as glyoxal among formaldehyde-free alternatives; polycarboxylic acids leading next generation. Via Consensus. Reference record Peer-reviewed
- Harmonised classification — glyoxal (CAS 107-22-2), Regulation (EC) No 1272/2008 (CLP). EU. Skin Sens. 1 (H317), Muta. 2 (H341), Acute Tox. 4, Skin/Eye Irrit. 2, STOT SE 3; mutagenic in vitro, negative in in-vivo mouse micronucleus; not an IARC carcinogen. ECHA substance information Regulatory
Frequently asked questions
What is glyoxal and why is it on my sheets?
Glyoxal is a small reactive dialdehyde used as a durable-press (wrinkle-resist, "easy-care", "non-iron") finish on cotton and cellulosic bedding and clothing. It crosslinks the cellulose fibres so the fabric springs back instead of creasing. Its main selling point is that, unlike the traditional durable-press resins, it is formaldehyde-free — so it became a leading replacement once formaldehyde was recognised as a carcinogen.
Is glyoxal safer than formaldehyde finishes?
On the cancer axis, yes — and that matters. Formaldehyde is an IARC Group 1 human carcinogen, and durable-press resins based on it release formaldehyde during wear. Glyoxal is not an IARC-classified carcinogen, so switching to it removes the formaldehyde-release problem. But "formaldehyde-free" does not mean inert: glyoxal is itself a reactive aldehyde carrying an EU harmonised classification as a skin sensitiser and a suspected mutagen. It is a genuine improvement on one hazard, not a clean bill of health.
What are glyoxal's actual hazards?
Under the EU's harmonised CLP classification, glyoxal is a skin sensitiser (may cause an allergic skin reaction), a suspected mutagen (Muta. 2), and an irritant to skin, eyes and the respiratory tract. It is mutagenic in laboratory (in vitro) tests but was negative in the in-vivo mouse micronucleus test, and it is not classified as a carcinogen by IARC. For bedding, the practical concerns are skin sensitisation and irritation from residual finish, especially before a first wash.
How is durable-press finishing regulated?
The regulation targets formaldehyde release rather than glyoxal specifically. Japan's Law 112 effectively bans detectable free formaldehyde in infant textiles and caps it in others; China's GB 18401 and the EU and many other markets set formaldehyde-release limits for skin-contact textiles; and OEKO-TEX Standard 100 sets strict formaldehyde limits (and screens other harmful residues). Those formaldehyde limits are precisely what pushed the industry toward glyoxal and other formaldehyde-free finishes — while glyoxal's own hazards are governed by chemical-classification law such as EU CLP.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress. This page is informational and is not medical advice.
Last reviewed 2026-06-29. If you find a factual error, contact us.