At a glance
| Chemical family | A polycyclic synthetic musk (fragrance); trade name Tonalide. The sibling of HHCB, with which it dominates the synthetic-musk market |
| CAS number | 1506-02-1 |
| Classification | Restricted in EU cosmetics under Annex III (safe within set limits after SCCS assessment). Bioaccumulative; more toxic to aquatic organisms than HHCB |
| Where you encounter it | Perfumes, cosmetics, and perfumed laundry detergents and softeners. The bedroom route is fabric deposition from scented laundry, plus transfer from skin-applied scented products |
| Sleep micro-environment relevance | Designed to persist on fabric; bioaccumulative and found in human breast milk (second to HHCB). Measured levels have been declining over time |
| Activated carbon capture | Not the lever — fragrance-free laundry and personal-care products remove it at the source |
Regulatory & certification status
Where AHTN (Tonalide) stands across the major regulatory systems and the certifications a bedroom 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 | AHTN (Tonalide; CAS 21145-77-7, also cited as 1506-02-1 for the same substance) is REACH-registered. It is controlled under the EU Cosmetic Products Regulation (EC) No 1223/2009, Annex III, reference 182, which caps it at 0.1% in leave-on and 0.2% in rinse-off cosmetic products, with category-specific limits (leave-on hydroalcoholic products 1%, fine fragrance 2.5%, fragrance cream 0.5%). It does not appear on the REACH SVHC Candidate List or the Authorisation List (Annex XIV), is not restricted under Annex XVII, and has no harmonised CLP classification in Annex VI as of this review; those negative findings could not be independently verified against ECHA's databases (bot-blocked) and should be treated as provisional. Regulatory — UK legislation · EUR-Lex |
| United States | AHTN (Tonalide) is on the TSCA Chemical Substance Inventory but is not subject to any TSCA risk evaluation or restriction. EPA's TSCA Work Plan risk assessment of polycyclic musks addressed the related compound HHCB (galaxolide), not AHTN. AHTN is not listed on California's Proposition 65: a review of the current OEHHA Proposition 65 list found no entry for Tonalide/AHTN, for CAS 21145-77-7 or 1506-02-1 (both identifiers refer to the same substance), or for any polycyclic musk. Regulatory — US EPA · OEHHA |
| Canada | No final CEPA screening assessment concluding specifically on AHTN (Tonalide) could be located. The draft's attribution to the 'Macrocyclic Lactones and Ketones, Ionones and Cyclohexanone Group' assessment (En14-382/2019E, 2019) is incorrect: although that group is informally labelled the 'Musks (macro/poly cyclic) Group,' the 11 substances it actually assessed (exaltolide, hexadecanolide, exaltone, muscone, civetone, ambrettolide, isoambrettolide, ambrettone, irone, 1-methyl-alpha-ionone and cyclohexanone) are macrocyclic musks, ionones and cyclohexanone — AHTN, a polycyclic (acetyltetralin) musk, is not among them. AHTN's Canadian regulatory status could not be independently confirmed from a primary final assessment. Regulatory — Government of Canada |
| Australia | NICNAS (now AICIS) assessed AHTN under the IMAP program. The Human Health Tier II assessment for Tonalide concluded that hazard classification for skin sensitisation was not warranted (negative human sensitisation/photosensitisation data; no structural alerts). The Environment Tier II assessment ('Tonalide and related polycyclic musks') concluded that AHTN itself is not a PBT substance under domestic environmental hazard criteria, while identifying a potential risk to aquatic life and soil from sewage-treatment-plant effluent and biosolids (note: two related substances in that group, versalide and 7-acetyl-1,1,4,4,6-pentamethyltetralin, were categorised as persistent and bioaccumulative). No formal use restriction or scheduling was imposed. Regulatory — AICIS |
| United Kingdom | Great Britain inherits the EU cosmetics position: AHTN (Tonalide) is capped under the assimilated UK Cosmetics Regulation (assimilated Regulation (EC) No 1223/2009), Annex III reference 182, at the same limits (0.1% leave-on / 0.2% rinse-off, with the fine-fragrance, fragrance-cream and hydroalcoholic category exceptions). It is registrable under UK REACH. No GB-specific SVHC identification or mandatory GB-CLP classification was confirmed in this review; that negative finding is provisional, as GB regulatory databases were not independently checked. Regulatory — UK legislation |
| Certifications | CertiPUR-US: not addressed — AHTN is a fragrance additive, outside the program's foam-emissions / heavy-metals / regulated-substance scope. OEKO-TEX STANDARD 100: not confirmed — it was not possible to verify that AHTN (or polycyclic musks generally) is individually named with a limit value in the published STANDARD 100 criteria; treat any 'restricted under OEKO-TEX' claim as unverified. GREENGUARD / GREENGUARD Gold: a low-VOC chamber-emissions certification that does not specifically screen for a semi-volatile musk fixative like AHTN. Industry — OEKO-TEX · CertiPUR-US |
| The 72-hour test window | Largely missed. AHTN is a semi-volatile fixative musk (used precisely because it is low-volatility and long-lasting) that migrates into and partitions to house dust rather than off-gassing freely, so a short ~72h VOC emissions chamber test does not reliably capture it. Inferred — from the compound's volatility/emission profile versus the VOC focus of short chamber tests |
What it is
AHTN is a polycyclic synthetic musk — a lab-made fragrance molecule that, with HHCB, replaced the natural and nitro musks of earlier eras. The two are the workhorses of modern scent, used across perfumes, cosmetics and household products. Regulatory — EU Cosmetics Regulation, Annex III Functionally it behaves almost identically to its sibling, which is why this page is shorter: the bedroom story is the same one told on the HHCB page, with a few meaningful differences in the regulatory and environmental detail.
Like HHCB, AHTN is built to last on fabric and is bioaccumulative. In a study of synthetic musks in mothers' milk, AHTN was the second-most abundant musk after HHCB, and — the detail that matters for sleep — elevated AHTN was associated specifically with the use of perfumed laundry detergent. Peer-reviewed — Lignell et al. 2008
How it relates to the bedroom
The same laundry-and-skin pathway
AHTN gets onto bedding the two ways HHCB does: it is added to perfumed detergents and fabric softeners that are designed to leave scent on fabric, so it persists on sheets and pillowcases through repeated nights of skin contact; and it transfers from scented skin and hair products used before bed. The breast-milk association with perfumed laundry detergent makes the laundry route concrete. Peer-reviewed — Lignell et al. 2008 Everything said about the personal-care exposure pattern on the HHCB page applies here.
Where it differs from HHCB
Three differences are worth stating, because they shape the honest verdict. First, regulation: AHTN is restricted — not banned — in EU cosmetics under Annex III, meaning regulators have set conditions (such as maximum concentrations) under which its use is considered safe. Regulatory — EU Cosmetics Regulation, Annex III entry 182 Second, trend: breast-milk monitoring found AHTN concentrations declining significantly over the years studied, suggesting reduced industrial use — a more encouraging trajectory than HHCB, whose levels did not fall in the same study. Peer-reviewed — Lignell et al. 2008 Third, environment: AHTN is somewhat more toxic to freshwater and marine organisms than HHCB, so its clearest documented harm is ecological. Peer-reviewed — Li et al. 2022
The calm verdict
Taken together: AHTN is a bioaccumulative fragrance that ends up on your bedding and in your body, which is reason enough to reduce avoidable exposure — especially during pregnancy and nursing, given the breast-milk findings. But it sits within EU cosmetic limits, its use has been trending down, and its strongest evidence of harm is to aquatic life rather than to people at current exposure levels. Inferred — weighing the bioaccumulation against the regulatory limits, declining trend, and predominantly ecological toxicity A reduce-where-easy compound, handled by the same fragrance-free choices as its sibling.
What the research says
- It is bioaccumulative. Second-most abundant musk in human breast milk after HHCB. Peer-reviewed — Lignell et al. 2008
- Perfumed laundry detergent is a documented source. Elevated AHTN tracked with its use. Peer-reviewed — Lignell et al. 2008
- Its use has been declining. Breast-milk levels fell over the monitoring period. Peer-reviewed — Lignell et al. 2008
- It is EU-restricted and aquatically toxic. Annex III cosmetic limits; more toxic to aquatic organisms than HHCB. Regulatory — EU Annex III Peer-reviewed — Li et al. 2022
What helps reduce it
Wash bedding in fragrance-free detergent. The most effective bedroom step, since laundry fragrance is meant to stay on the fabric you sleep against. Peer-reviewed — Lignell et al. 2008
Skip scented fabric softener and dryer sheets. Their purpose is to deposit fragrance — including musks — onto fabric. Inferred — softeners and dryer sheets deposit fabric fragrance by design
Use fragrance-free skin and hair products at bedtime. The skin route is the dominant exposure pathway for synthetic musks generally. Peer-reviewed — Luo et al. 2023
What does NOT help
- Trusting "unscented." Masking musks are often added to "unscented" products; the meaningful label is "fragrance-free." Inferred
- Air purifiers. AHTN arrives on fabric and skin, not as an air pollutant to be filtered. Inferred
Open research questions
- Whether the decline in AHTN body burden has continued since the mid-2000s, and how it now compares with HHCB. Speculation
- The real-world transfer of AHTN from fragranced bedding to skin over a night's sleep. Speculation
Citations
- Lignell S, et al. (2008). Temporal trends of synthetic musk compounds in mother's milk and associations with personal use of perfumed products. Environmental Science & Technology. AHTN second to HHCB in breast milk; elevated AHTN with perfumed laundry detergent; AHTN declined 1996–2003. Via Consensus. DOI 10.1021/es800626n Peer-reviewed
- Li W, et al. (2022). Derivation of predicted no effect concentration and ecological risk assessment of polycyclic musks tonalide and galaxolide in sediment. Ecotoxicology and Environmental Safety. AHTN and HHCB persistent/bioaccumulative; AHTN more toxic to aquatic organisms than HHCB. Via Consensus. DOI 10.1016/j.ecoenv.2021.113093 Peer-reviewed
- EU Cosmetics Regulation (EC) No 1223/2009, Annex III entry 182 — Acetyl Hexamethyl Tetralin (AHTN / Tonalide). Restricted under set conditions following SCCS assessment; safe within those limits. Documented in the Cosmetics Europe COSMILE database. cosmileeurope.eu Regulatory
Frequently asked questions
What is AHTN, and how is it different from HHCB?
AHTN — trade name Tonalide — is a synthetic polycyclic musk, and together with HHCB (Galaxolide) it makes up the large majority of polycyclic musks used in consumer products. The two are siblings with the same role and the same bedroom pathway: fragrance in perfumes, cosmetics and laundry products that deposits on fabric and skin. The main differences are regulatory and environmental — AHTN is restricted in EU cosmetics under Annex III, its measured use has been declining, and it is somewhat more toxic to aquatic life than HHCB.
How does AHTN get onto my bedding?
The same two ways HHCB does. It is added to perfumed laundry detergents and fabric softeners, which are designed to leave fragrance on fabric, so it persists on sheets and pillowcases; and it transfers from scented skin and hair products applied before bed. A breast-milk study found elevated AHTN specifically among women who used perfumed laundry detergent, which makes the laundry route concrete rather than theoretical.
Is AHTN dangerous?
Like its sibling, AHTN is bioaccumulative and is detected in human breast milk and tissue, so it is reasonable to reduce avoidable exposure — particularly during pregnancy and nursing. It is restricted (not banned) in EU cosmetics under Annex III, meaning regulators consider it safe within set limits. Encouragingly, breast-milk monitoring showed AHTN levels declining over time, suggesting reduced use. Its clearest documented harm is environmental: it is more toxic to aquatic organisms than HHCB.
How do I reduce AHTN exposure?
Exactly as for HHCB: wash bedding in fragrance-free detergent, skip scented fabric softener and dryer sheets, and choose fragrance-free skin and hair products for use before bed. Remember that "unscented" products can still contain masking musks — "fragrance-free" is the label that signals no added fragrance.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-06-27. If you find a factual error, contact us.