Body & Beauty / Compounds / Formaldehyde

Formaldehyde on your skin: a safety profile

Moderate risk

Contact dermatitis from preservatives in cosmetics/shampoos; absorption minimal vs inhalation.

What is formaldehyde?

Also known as: formalin, methanal, formol, Formic aldehyde.

IUPAC name
formaldehyde
CAS number
50-00-0
Molecular formula
CH2O
Molecular weight
30.026 g/mol
SMILES
C=O
PubChem CID
712

Risk for people

Moderate risk

Contact dermatitis from preservatives in cosmetics/shampoos; absorption minimal vs inhalation.

Regulatory consensus

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

AgencyYearClassificationNotes
IARC2012Group 1 (carcinogenic to humans)Nasopharyngeal cancer, leukemia; Monograph 100F
US EPA2010Likely to be carcinogenic to humansDraft IRIS assessment; leukemia; inhalation route
EPA CTX / NIOSH—potential occupational carcinogen
EPA CTX / IRIS—B1 (Probable human carcinogen - based on limited evidence of carcinogenicity in humans)
EPA CTX / NTP RoC—Known Human Carcinogen
EPA CTX / IARC—Group 1 - Carcinogenic to humans
EPA CTX / EPA OPP—Group B1 Probable Human Carcinogen
EPA CTX / CalEPA—Known human carcinogen
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 32 positive / 8 negative reports)
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 32 positive / 8 negative reports)
EPA CTX / Skin-Eye—Skin Irritation: Skin Corr. 1B (score: very high)
EPA CTX / Skin-Eye—Skin Sensitization: Skin Sens. 1 (score: high)
EPA CTX / Skin-Eye—Skin Sensitization: Sh (score: high)
EPA CTX / Skin-Eye—Skin Irritation: Skin corrosion - category 1 (score: very high)
EPA CTX / Skin-Eye—Skin Sensitization: Skin sensitisation - category 1 (score: high)
EPA CTX / Skin-Eye—Eye Irritation: Serious eye damage/eye irritation - Category 2 (score: high)
EPA CTX / Skin-Eye—Eye Irritation: Eye Dam. 1 (score: very high)
EPA CTX / Skin-Eye—Skin Irritation: Skin Corr. 1B (score: very high)
EPA CTX / Skin-Eye—Skin Sensitization: Skin Sens. 1 (score: high)
EPA CTX / Skin-Eye—Eye Irritation: Category 8.3A (Category 1) (score: very high)
EPA CTX / Skin-Eye—Skin Irritation: Category 8.2C (Category 1C) (score: very high)
EPA CTX / Skin-Eye—Skin Sensitization: Category 6.5B (Category 1) (score: moderate)
EPA CTX / Skin-Eye—Eye Irritation: Category 6.4A (Category 2A) (score: high)
EPA CTX / Skin-Eye—Skin Irritation: Category 6.3A (Category 2) (score: high)
EPA CTX / Skin-Eye—skin sensitisation: in vivo (LLNA): High Frequency of Sensitization (score: high)
EPA CTX / Skin-Eye—skin sensitisation: in vivo (non-LLNA): Ambiguous (score: not classifiable)
EPA CTX / Skin-Eye—skin sensitisation: in vivo (non-LLNA): High Frequency of Sensitization (score: high)
EPA CTX / Skin-Eye—skin irritation: in vivo: Corrosive (score: very high)

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 formaldehyde

  • Building Materials And Indoor Air — Pressed wood products (plywood, particleboard), Fiberglass insulation, Foam insulation
    Off-gassing occurs especially in new products and is accelerated by heat and humidity
  • Personal Care And Household Products — Cosmetics and toiletries, Cleaning products, Air fresheners
    Used as preservative in cosmetics and as antimicrobial agent in household cleaners
  • Industrial And Occupational Settings — Textile manufacturing and fabric finishing, Wood processing facilities, Anatomy and pathology laboratories
    Workers in these settings face elevated inhalation exposure; classified as IARC Group 1 carcinogen
  • Medical And Laboratory Use — Embalming and tissue preservation, Histology laboratories, Medical sterilization
    Occupational exposure in healthcare and research settings

Safer alternatives

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

  • MDI (Methylene diphenyl diisocyanate) for wood products
    Trade-offs: Higher cost. Isocyanate occupational exposure during manufacturing.
    Relative cost: 1.2-2×
  • Soy-based adhesives
    Trade-offs: Lower moisture resistance than UF resin. Higher cost.
    Relative cost: 2-5×
  • Physical/mechanical pest control (IPM)
    Trade-offs: More labor-intensive. May not be sufficient for severe infestations.
    Relative cost: Variable; lower long-term

Frequently asked questions

Is formaldehyde safe for you?

Contact dermatitis from preservatives in cosmetics/shampoos; absorption minimal vs inhalation.

What products contain formaldehyde?

Formaldehyde appears in: Pressed wood products (plywood, particleboard) (Building materials and indoor air); Fiberglass insulation (Building materials and indoor air); Cosmetics and toiletries (Personal care and household products); Cleaning products (Personal care and household products); Textile manufacturing and fabric finishing (Industrial and occupational settings).

Why do regulators disagree about formaldehyde?

Formaldehyde has been classified by 28 agencies including IARC, US EPA, EPA CTX / NIOSH, EPA CTX / IRIS, EPA CTX / NTP RoC, 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 Formaldehyde in the body app

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

Open in body View raw API data

Sources (2)
  1. IARC Monographs Volume 100F: Formaldehyde (2012) — regulatory
  2. US EPA IRIS Assessment: Formaldehyde (draft) (2010) — 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 →