Body & Beauty / Compounds / Butyraldehyde

Butyraldehyde on your skin: a safety profile

Low risk

(People-specific data is limited; this page draws from human adult context.) Butyraldehyde presents low risk to human adults from a toxicological perspective. No carcinogenicity classification by IARC, NTP, or EPA. The primary hazard is flammability (flash point -6°C; highly flammable liquid and vapor — this is the dominant safety concern in industrial settings) rather than health toxicity. As a chemical intermediate, occupational exposure in industrial synthesis (Oxo process, plasticizer precursor manufacture) requires standard vapour exposure controls (LEV, explosion-proof equipment) due to flammability. Health effects at elevated concentrations include eye and mucous membrane irritation, narcosis, and headache. Butyraldehyde in foods (as natural flavoring and fragrance) at typical dietary levels is of no toxicological concern; FDA GRAS status for food flavor use is consistent with the safety profile. Metabolism to butyric acid (via ALDH) produces a physiologically normal SCFA metabolite.

What is butyraldehyde?

The IUPAC name is butanal.

Also known as: butanal, n-butyraldehyde, Butyral, 1-butanal.

IUPAC name
butanal
CAS number
123-72-8
Molecular formula
C4H8O
Molecular weight
72.11 g/mol
SMILES
CCCC=O
PubChem CID
261

Risk for people

Low risk

Butyraldehyde presents low risk to human adults from a toxicological perspective. No carcinogenicity classification by IARC, NTP, or EPA. The primary hazard is flammability (flash point -6°C; highly flammable liquid and vapor — this is the dominant safety concern in industrial settings) rather than health toxicity. As a chemical intermediate, occupational exposure in industrial synthesis (Oxo process, plasticizer precursor manufacture) requires standard vapour exposure controls (LEV, explosion-proof equipment) due to flammability. Health effects at elevated concentrations include eye and mucous membrane irritation, narcosis, and headache. Butyraldehyde in foods (as natural flavoring and fragrance) at typical dietary levels is of no toxicological concern; FDA GRAS status for food flavor use is consistent with the safety profile. Metabolism to butyric acid (via ALDH) produces a physiologically normal SCFA metabolite.

Regulatory consensus

3 regulatory and scientific bodies have classified Butyraldehyde. The classifications differ — that's the data.

AgencyYearClassificationNotes
IARC2023Not evaluated — butyraldehyde has not been classified by IARC as to carcinogenicity; it is a saturated short-chain aliphatic aldehyde with primary concerns as a flammable VOC and irritant; used as a fragrance ingredient and chemical intermediate; naturally present in many foods
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 2 positive / 2 negative reports)
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 2 positive / 2 negative reports)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where you encounter butyraldehyde

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles
  • Fragrance — perfume, cologne, scented personal care products, household fragrance products, candles
    Identified in Fragrance Ingredient Safety Priority Research database (2,325 ingredients)

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Butyraldehyde:

  • Fragrance-free formulations
    Trade-offs: Consumer preference for scented products
    Relative cost: Lower (ingredient elimination)
  • Essential oil-based fragrances (with disclosure)
    Trade-offs: Natural does not mean safe — many essential oils are skin sensitizers
    Relative cost: 2-5× conventional

Frequently asked questions

What products contain butyraldehyde?

Butyraldehyde appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); perfume (Fragrance).

Why do regulators disagree about butyraldehyde?

Butyraldehyde has been classified by 3 agencies including IARC, EPA CTX / Genetox, EPA CTX / Genetox, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See Butyraldehyde in the body app

Look up products containing butyraldehyde, compare to alternatives, and explore the full data record.

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Sources (1)
  1. Butyraldehyde n-Butanal IARC Not Evaluated; EU CLP Flam Liq 3 H226 Flash Point -6C; Acute Tox 4 H302 H312 H332; No CMR Classification; FDA GRAS Fragrance Flavoring 21 CFR 172.515; Oxo Process Hydroformylation Propylene; 2-Ethylhexanol DEHP Plasticizer Precursor; ALDH Metabolism Butyric Acid SCFA HDAC Inhibitor; FEMA GRAS; Readily Biodegradable Not PBT (2023) — regulatory

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →