Volatile organic compound — microbial VOC (mold biomarker)

1-Octen-3-ol in the bedroom

By — 19-year firefighter and entrepreneur. Published July 2026.

1-Octen-3-ol — commonly called 'mushroom alcohol' — is the volatile organic compound most strongly associated with the musty odour of mold growth. It is produced by a wide range of indoor molds including Aspergillus, Penicillium, and Stachybotrys species. IARC has not classified 1-octen-3-ol for carcinogenicity. Its significance in the bedroom is as a biomarker: when 1-octen-3-ol is detected in indoor air, it strongly suggests hidden mold growth, even when no mold is visible. It has an extremely low odour threshold — approximately 1 part per billion (ppb) — making it detectable by human smell at very low concentrations.

1-Octen-3-ol — Embr Bedroom Chemistry Atlas

At a glance

Chemical familyMicrobial volatile organic compound (MVOC) — C8 unsaturated alcohol produced by mold metabolism
CAS number3391-86-4
ClassificationNot classified by IARC. Not classified as a carcinogen or reproductive toxicant. Primary significance is as a mold biomarker. At higher concentrations, causes eye and respiratory irritation
Where you encounter itIndoor air in buildings with mold growth (behind walls, under flooring, in HVAC systems); mushroom cultivation facilities; forests and outdoor environments with decomposing organic matter
Sleep micro-environment relevanceA diagnostic indicator of hidden mold in bedrooms. The musty smell that prompts mold investigations is largely 1-octen-3-ol. Mold in the bedroom is associated with respiratory symptoms and disturbed sleep

Regulatory & certification status

European UnionNo specific regulation for 1-octen-3-ol in indoor air. REACH registered substance. Recognised as an MVOC indicator of mold growth in European building investigation standards. Regulatory
United StatesNo EPA indoor air quality standard. Recognised by ACGIH and AIHA as an MVOC indicator. Used in mold assessment protocols by indoor air quality professionals. Regulatory
CanadaNo Health Canada indoor air quality guideline for 1-octen-3-ol. Health Canada's Residential Indoor Air Quality Guideline on Moulds addresses mold broadly. Regulatory
InternationalNot IARC classified. WHO Guidelines for Indoor Air Quality on Dampness and Mould (2009) address mold-related health effects broadly. 1-Octen-3-ol is one of the MVOC indicators referenced in building investigation literature. Regulatory

What it is

1-Octen-3-ol is a C8 secondary alcohol with one double bond. It is the primary volatile compound responsible for the characteristic odour of fresh mushrooms and is produced by a broad range of fungi through the enzymatic oxidation and cleavage of linoleic acid. In the indoor environment, 1-octen-3-ol is classified as a microbial VOC (MVOC) — a volatile compound produced specifically by microbial metabolism rather than by building materials. Its presence in indoor air is considered a strong indicator of active mold growth. IARC has not evaluated 1-octen-3-ol. Toxicological studies in Drosophila and cell culture models have shown that 1-octen-3-ol can cause dopaminergic neuron degeneration at high concentrations, but the relevance to human health at typical indoor air levels is not established.

Where it shows up in bedding

1-Octen-3-ol is not a bedding ingredient. In the bedroom, it signals a problem: active mold growth somewhere in the room. Common hidden mold sites in bedrooms include behind headboards against exterior walls (condensation), inside wall cavities with water damage, under carpet with moisture intrusion, and in HVAC ducts. When occupants report a persistent musty smell in the bedroom — especially one that is stronger in the morning after a night of doors-and-windows-closed sleeping — 1-octen-3-ol from hidden mold is the likely cause. Addressing the underlying mold growth (moisture control and remediation) eliminates the 1-octen-3-ol exposure.

Citations

  1. WHO (2009). WHO Guidelines for Indoor Air Quality: Dampness and Mould. Source Regulatory
  2. Korpi, A. et al. (2009). Microbial Volatile Organic Compounds. Critical Reviews in Toxicology, 39(2): 139-193. Source Peer-reviewed
  3. Inamdar, A.A. et al. (2013). Fungal-Derived Semiochemical 1-Octen-3-ol Disrupts Dopamine Packaging and Causes Neurodegeneration. Proceedings of the National Academy of Sciences, 110(48): 19561-19566. Source Peer-reviewed

Frequently asked questions

  • Does a musty bedroom smell mean I have mold?

    A persistent musty smell — especially one that is stronger in the morning after sleeping with doors and windows closed — is a strong indicator of hidden mold growth. The compound most responsible for this smell is 1-octen-3-ol, produced by mold metabolism. Not every musty smell is mold, but it warrants investigation. Check behind headboards, along exterior walls, under carpets, and inside HVAC registers.

  • Can mold in the bedroom affect sleep?

    Yes. The WHO Guidelines on Dampness and Mould (2009) concluded that living in damp, mold-affected buildings is associated with respiratory symptoms, asthma exacerbation, and allergic rhinitis — all of which can disturb sleep. The MVOCs produced by mold (including 1-octen-3-ol) can also cause eye and respiratory irritation. Addressing the underlying moisture problem and remediating the mold growth is the correct response.

Related compounds

  • Formaldehyde — another indoor air irritant that affects sleep quality
  • Hexanal — an aldehyde VOC found in indoor air
  • VOCs — the broader class of volatile organic compounds

Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.

Last reviewed 2026-07-08. If you find a factual error, contact us.