At a glance
| Chemical class | Aluminum-based antiperspirant actives: aluminum chlorohydrate (a basic aluminum chloride) and aluminum-zirconium complexes (e.g., aluminum zirconium tetrachlorohydrex gly), often combined with glycine |
| CAS numbers | Aluminum chlorohydrate: 12042-91-0. Aluminum zirconium tetrachlorohydrex gly: 57158-29-9 (the most widely cited INCI CAS; several closely related AZG variants carry their own CAS numbers, e.g. 90604-80-1, 134910-86-4) |
| Carcinogen status | Not classified as a carcinogen by IARC, not listed on California Proposition 65, and not linked to breast cancer by NCI or a 2014 systematic review — despite a widely circulated myth to the contrary |
| Where you encounter it | Underarm antiperspirants and "clinical strength" deodorant-antiperspirant combination products, applied to skin, typically including before bed |
| Sleep micro-environment relevance | A leave-on personal-care residue that transfers from skin onto pillowcases, sheets and sleepwear overnight — the same mechanism as fabric yellowing on shirts — plus a real, non-cancer contact-dermatitis and granulomatous-reaction risk |
| Activated carbon capture | Not the lever — this is a skin-and-fabric residue, not an airborne compound; product choice and laundering are what matter |
Regulatory & certification status
Where aluminum chlorohydrate and aluminum-zirconium antiperspirant salts stand across the major regulatory systems and the certifications a bedroom or personal-care product might carry. Each row links to the governing instrument; where a jurisdiction has no specific measure, that is stated plainly rather than left blank.
| European Union | Aluminum compounds are permitted cosmetic ingredients under the Cosmetics Regulation (EC) 1223/2009. Following its 2020 opinion, the Scientific Committee on Consumer Safety (SCCS) concluded that aluminum is safe in antiperspirants and deodorants at equivalent-aluminum concentrations up to 6.25% in non-spray products and 10.60% in spray products (and separately assessed limits for toothpaste and lipstick), and that daily cosmetic exposure does not add significantly to the body's overall aluminum burden from other sources such as diet. Neither aluminum chlorohydrate nor the aluminum-zirconium complexes carry a REACH SVHC Candidate List entry or an Annex XVII restriction. Regulatory — SCCS Opinion SCCS/1613/19 |
| United States | Aluminum chlorohydrate and aluminum-zirconium complexes (including aluminum zirconium tetrachlorohydrex gly) are permitted active ingredients under the FDA's Antiperspirant Drug Products for Over-the-Counter Human Use monograph (21 CFR 350), at concentration limits that vary by specific salt and product form (commonly up to 15-25% depending on formulation). Neither aluminum nor aluminum chlorohydrate appears on the California Proposition 65 list of chemicals known to cause cancer or reproductive harm — verified directly against the current OEHHA-maintained list and the state's own consumer-facing Prop 65 warnings site. Regulatory — FDA Federal Register Final Monograph · California Prop 65 Warnings site |
| Canada | Aluminum chlorohydrate and aluminum-zirconium antiperspirant actives are regulated as non-prescription drugs under Health Canada's antiperspirant monograph framework (parallel in structure to the FDA's), requiring a Natural Product Number or Drug Identification Number rather than falling under the general Cosmetic Ingredient Hotlist. No CEPA Schedule 1 (List of Toxic Substances) listing applies to either compound. Regulatory — Health Canada antiperspirant/deodorant product licensing framework |
| International — cancer classification | Neither aluminum chlorohydrate nor aluminum-zirconium antiperspirant complexes have a specific IARC monograph evaluation or classification. The National Cancer Institute (a US federal regulatory/research body) states directly that no scientific evidence links antiperspirant or deodorant use — including their aluminum-based active ingredients — to the development of breast cancer. Regulatory — National Cancer Institute fact sheet |
| Certifications | None of the major sleep-product certifications name aluminum antiperspirant salts, because they are cosmetic actives rather than foam, mattress, or textile-finish chemistries. CertiPUR-US: not applicable — its criteria screen foam-relevant chemistries and heavy metals such as lead and mercury, not personal-care antiperspirant actives. OEKO-TEX Standard 100: not applicable — its scope is textile content and finishing chemicals, not skin-applied cosmetic ingredients that arrive on fabric as user residue. GREENGUARD/GREENGUARD Gold: a chemical-emissions certification for low-volatility indoor air, and aluminum salts are non-volatile, so this framework does not evaluate them. Industry — CertiPUR-US · OEKO-TEX |
| The 72-hour test window | Entirely missed. Aluminum chlorohydrate and aluminum-zirconium salts are non-volatile inorganic/organometallic solids with no meaningful vapor pressure; they do not off-gas, so a short chamber VOC emissions test is the wrong tool for detecting them — they are a skin-and-fabric-residue question, not an air-quality one. Inferred — from the compounds' non-volatile physical form versus the VOC focus of short chamber tests |
What it is
Aluminum chlorohydrate is a basic aluminum chloride salt — the workhorse antiperspirant active ingredient found in most drugstore sticks, roll-ons, and sprays. Aluminum-zirconium complexes, most commonly aluminum zirconium tetrachlorohydrex gly, are a related but chemically distinct family that pairs aluminum with zirconium and the amino acid glycine; they are the actives typically used in "clinical strength" or extended-protection formulas. Both work the same way: applied to the underarm, they react with sweat to form a temporary gel that mechanically plugs the eccrine sweat duct, reducing the amount of sweat that reaches the skin's surface. Industry — chemistry and mechanism as described in FDA antiperspirant monograph documentation Both are permitted, monograph-reviewed OTC drug actives in the US and equivalently regulated in Canada and the EU. Regulatory — FDA Final Monograph; SCCS Opinion SCCS/1613/19
Correcting the record: the breast-cancer myth
Where the idea came from
The hypothesis is intuitive on its face: antiperspirants are applied daily, close to breast tissue, and contain aluminum compounds that some laboratory work suggests can be weakly absorbed through skin and show hormone-like activity. A small number of scientists — most prominently a research group publishing through the 2000s and 2010s — proposed that this combination could plausibly contribute to breast cancer risk, and speculated that aluminum might have direct biological activity in breast tissue. Peer-reviewed — the hypothesis is documented and cited directly in NCI's own fact sheet That is a legitimate scientific question to raise — and it has since been tested directly, more than once.
What the direct research found
The most relevant direct test is a 2002 case-control study of 813 women with breast cancer and 793 women without, which found no increase in breast-cancer risk associated with antiperspirant or deodorant use — including no increased risk among women who used a blade razor and an antiperspirant together, or who used an antiperspirant within an hour of shaving. Peer-reviewed — Mirick, Davis & Thomas 2002, JNCI A smaller 2006 study reached the same conclusion. A separate 2003 retrospective study did report an association between earlier breast-cancer diagnosis age and more frequent antiperspirant/shaving use, but its own authors flagged that a retrospective design of that kind cannot establish cause and effect — it is exactly the type of study that generates a hypothesis rather than confirms one. Peer-reviewed — NCI fact sheet, summarizing McGrath 2003
Zooming out from individual studies, a comprehensive 2014 systematic review of the health effects of metallic and soluble aluminum compounds — covering pharmaceutical, occupational, and consumer exposures — concluded there was no clear evidence that aluminum-containing underarm antiperspirants or cosmetics increase the risk of breast cancer. Peer-reviewed — Willhite et al. 2014, Critical Reviews in Toxicology The US National Cancer Institute's own synthesis of the evidence states it without hedging: "no scientific evidence links the use of these products to the development of breast cancer." Regulatory — National Cancer Institute
Being honest about the limits of the evidence
The fair caveat, which NCI itself makes, is that only a handful of studies have looked at this question directly, results have not been perfectly uniform, and the agency notes that additional research could still refine the picture. Regulatory — National Cancer Institute That is normal, honest science-in-progress language — it is not the same as "the link is real but unconfirmed." On the current weight of evidence, including a purpose-built case-control study and an exhaustive systematic review, the hypothesis has been tested and has not been supported. We report it that way rather than hedge it into false balance. This corrects an earlier internal gap-analysis note that had listed these compounds as carcinogens; on the evidence we could verify, that was incorrect.
What actually is worth knowing for the bedroom
A leave-on residue that ends up on your pillowcase
Set the cancer question aside, and there is a real, ordinary bedroom mechanism here: antiperspirant is a leave-on underarm product, and unless it is fully washed off, whatever remains transfers onto the fabric that touches it — sleepwear collars and sleeves, and by extension pillowcases and sheets over a night of contact and movement. Inferred — leave-on personal-care residues transfer onto bedding, as documented for the site's other personal-care entries The clearest visible evidence of this transfer is the yellow underarm staining familiar on white and light-colored shirts: aluminum salts react with sweat and body oils over repeated wear-and-launder cycles, and that same aluminum-plus-sweat chemistry is what deposits onto any fabric in prolonged contact with treated skin. Inferred — fabric-staining mechanism from aluminum-salt/sweat/oil interaction, as documented in textile-care literature It is not a hazard in the sense this Atlas usually tracks, but it is a genuine, physical, bedroom-relevant residue pathway — the same category as the site's other leave-on personal-care entries.
The real risk: contact dermatitis, not cancer
Where these compounds do carry a documented, non-cancer health signal is skin allergy. A 2020 clinical review of cutaneous reactions to aluminum catalogs allergic contact dermatitis, and less commonly granulomatous dermatitis, specifically from aluminum chlorohydrate and aluminum-zirconium antiperspirant complexes, confirmed by patch testing in individual case reports. Peer-reviewed — Kullberg et al. 2020, Dermatitis A 2024 clinical review of axillary (underarm) contact dermatitis names aluminum — specifically including aluminum chlorohydrate and aluminum zirconium tetrachlorohydrex gly — among the recognized allergens found in antiperspirants, alongside fragrance and propylene glycol, and notes that the American Contact Dermatitis Society named aluminum its 2022 Allergen of the Year, recommending a higher patch-test concentration to improve diagnostic detection. Peer-reviewed — Musicante, Cohen & Milam 2024, Cutis A distinct, uncommon presentation — granulomatous dermatitis, red-brown itchy papules confined to the area of antiperspirant application — has also been reported specifically from aluminum-zirconium complexes. Peer-reviewed — Kullberg et al. 2020 (citing Montemarano et al. 1997) This is the honest hazard story for this compound class: not a cancer risk, but a real, if uncommon, dermatologic one.
What the research says
- No confirmed breast-cancer link. A purpose-built case-control study and a comprehensive 2014 systematic review both found no clear evidence of increased risk; NCI states this directly. Peer-reviewed — Mirick et al. 2002; Willhite et al. 2014 Regulatory — NCI
- Not a classified carcinogen by any body we could verify. No IARC monograph evaluation exists for either compound; neither is on California Proposition 65. Regulatory — OEHHA/Prop 65 Warnings site
- EU regulators judged it safe at defined limits. SCCS set concentration caps and found daily cosmetic exposure does not meaningfully add to the body's aluminum burden. Regulatory — SCCS Opinion SCCS/1613/19
- Contact dermatitis is the real, documented risk. Aluminum was named 2022's Allergen of the Year; both aluminum chlorohydrate and aluminum-zirconium complexes are named causes of axillary allergic and granulomatous dermatitis. Peer-reviewed — Kullberg et al. 2020; Musicante et al. 2024
- It transfers onto fabric. The same chemistry that yellows shirt underarms deposits residue onto any textile in prolonged contact with treated skin, including bedding. Inferred
What helps reduce it
If you get a persistent underarm rash, consider the antiperspirant, not cancer. Aluminum contact dermatitis is a real and recognized possibility; a dermatologist can patch-test for it, now at a higher recommended concentration for better detection. Peer-reviewed — Musicante et al. 2024
Let it dry before dressing or getting into bed. Applying antiperspirant and dressing immediately transfers more wet residue onto fabric than letting it set first — a simple, low-effort way to reduce buildup on sleepwear and pillowcases. Inferred — standard fabric-care guidance for residue transfer
Launder bedding and sleepwear normally. Ordinary washing removes the surface residue and prevents the aluminum-sweat-oil buildup that causes staining. Inferred
If you want to avoid aluminum salts specifically, aluminum-free "deodorant" products exist (they control odor without blocking sweat) — a preference choice, not a safety necessity. Inferred — labeling enables avoidance for those who prefer it
What does NOT help
- Switching products specifically to avoid breast cancer. The evidence does not support that this reduces any real risk; if you switch, do it for skin comfort or personal preference, not a cancer concern the data doesn't support. Regulatory — NCI
- Air purifiers or activated carbon. These are non-volatile solids on skin and fabric, not airborne compounds — filtration addresses a different problem entirely. Inferred
- Assuming a rash near the underarm is automatically an aluminum allergy. Fragrance is still the single most common antiperspirant/deodorant allergen; patch testing, not guessing, identifies the actual cause. Peer-reviewed — Musicante et al. 2024
Open research questions
- How much aluminum-salt residue actually transfers from a night of skin contact onto bedding fabric, in absolute terms. Speculation
- Whether repeated-launder aluminum buildup on textiles has any independent skin-contact implication beyond the antiperspirant application itself. Speculation
- Why aluminum contact allergy appears to be rising in prevalence enough to prompt its 2022 Allergen of the Year designation — better detection, higher exposure, or a genuine trend. Speculation
Citations
- National Cancer Institute (2016, reviewed). Antiperspirants/Deodorants and Breast Cancer. No scientific evidence links antiperspirant/deodorant use to breast cancer; cites a 2014 systematic review finding no clear evidence that aluminum-containing antiperspirants increase breast-cancer risk. cancer.gov Regulatory
- Mirick DK, Davis S, Thomas DB (2002). Antiperspirant use and the risk of breast cancer. Journal of the National Cancer Institute, 94(20):1578-1580. Case-control study (813 cases, 793 controls); no increased breast-cancer risk from antiperspirant/deodorant use. PMID 12381712. Oxford Academic / JNCI Peer-reviewed
- Willhite CC, Karyakina NA, Yokel RA, et al. (2014). Systematic review of potential health risks posed by pharmaceutical, occupational and consumer exposures to metallic and nanoscale aluminum, aluminum oxides, aluminum hydroxide and its soluble salts. Critical Reviews in Toxicology, 44(Suppl 4):1-80. No clear evidence aluminum antiperspirants increase breast-cancer risk. PMID 25233067. PubMed Peer-reviewed
- Kullberg SA, Ward JM, Liou YL, Atwater AR, Hylwa S, Neeley AB, Warshaw EM (2020). Cutaneous Reactions to Aluminum. Dermatitis, 31(6):335-349. Allergic and granulomatous contact dermatitis from aluminum chlorohydrate and aluminum-zirconium complexes; patch-test methodology. PMID 33186331. PubMed Peer-reviewed
- Musicante MJ, Cohen DE, Milam EC (2024). Axillary Contact Dermatitis: An Update on Potential Allergens and Management. Cutis, 113(1):35-42. Names aluminum chlorohydrate and aluminum zirconium tetrachlorohydrex gly as recognized axillary allergens; aluminum named 2022 Allergen of the Year. Cutis / MDedge (PDF) Peer-reviewed
- SCCS (Scientific Committee on Consumer Safety) (2020). Opinion on the safety of aluminium in cosmetic products - Submission II, SCCS/1613/19. Aluminum compounds safe up to 6.25% (non-spray) / 10.60% (spray) antiperspirants; no significant addition to systemic aluminum burden. European Commission Regulatory
- California OEHHA. Proposition 65 chemical list and consumer warnings site — aluminum and aluminum chlorohydrate are not listed chemicals. p65warnings.ca.gov Regulatory
- US FDA. Antiperspirant Drug Products for Over-the-Counter Human Use; Final Monograph, 21 CFR 350. Aluminum chlorohydrate and aluminum-zirconium complexes as permitted OTC antiperspirant actives. Federal Register Regulatory
Frequently asked questions
Do antiperspirants with aluminum chlorohydrate cause breast cancer?
No — this is one of the most persistent chemical-safety myths, and it is not supported by the evidence. The National Cancer Institute states plainly that no scientific evidence links antiperspirant or deodorant use to breast cancer. A 2002 case-control study of 813 breast-cancer patients and 793 controls found no increased risk from antiperspirant or deodorant use, and a comprehensive 2014 systematic review of aluminum health effects concluded there was no clear evidence that aluminum-containing antiperspirants increase breast-cancer risk. The hypothesis has been tested directly and repeatedly, and it has not held up.
What is aluminum chlorohydrate actually used for?
It is the workhorse active ingredient in over-the-counter antiperspirants — an FDA-monograph-approved compound that forms a temporary gel plug inside sweat ducts to reduce underarm perspiration. Aluminum-zirconium complexes (such as aluminum zirconium tetrachlorohydrex gly) do the same job and are common in the "clinical strength" and multi-day formulas. Both are cosmetic actives, not preservatives or fragrances — their entire function is blocking sweat.
How does an antiperspirant ingredient end up in the bedroom?
The same way other leave-on personal-care products do: it is applied to skin (the underarm, specifically) and never fully washed off before bed, so a night of contact transfers some of it onto pillowcases, sheets, and sleepwear. It is also the well-known cause of yellow underarm staining on fabric, a visible sign that aluminum salts, sweat, and body oils build up on textiles over repeated wear-and-launder cycles. This is a residue-and-laundry question, not an airborne one.
Is aluminum chlorohydrate safe to use?
For the general population, yes — it is an FDA OTC monograph active ingredient, and the EU's Scientific Committee on Consumer Safety concluded aluminum compounds are safe in antiperspirants up to defined concentration limits, with daily cosmetic use not meaningfully adding to the body's total aluminum burden. The genuine caution is different from cancer: aluminum salts are a recognized cause of contact dermatitis and, less commonly, granulomatous skin reactions, and the American Contact Dermatitis Society named aluminum its 2022 Allergen of the Year. If you get a persistent underarm rash, that — not cancer — is the mechanism worth investigating.
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 2026-07-07. If you find a factual error, contact us.