Body & Beauty / Compounds / 4-tert-Butylphenol

4-tert-Butylphenol on your skin: a safety profile

Elevated risk

(People-specific data is limited; this page draws from human adult context.) Endocrine disruptor (estrogenic); ECHA SVHC candidate; used in resins and adhesives; occupational exposure concern

What is 4-tert-butylphenol?

Also known as: p-tert-Butylphenol, Butylphen, 4-(1,1-Dimethylethyl)phenol, 4-t-Butylphenol.

IUPAC name
4-tert-butylphenol
CAS number
98-54-4
Molecular formula
C10H14O
Molecular weight
150.22 g/mol
SMILES
CC(C)(C)C1=CC=C(C=C1)O
PubChem CID
7393

Risk for people

Elevated risk

Endocrine disruptor (estrogenic); ECHA SVHC candidate; used in resins and adhesives; occupational exposure concern

Regulatory consensus

3 regulatory and scientific bodies have classified 4-tert-Butylphenol. The classifications differ — that's the data.

AgencyYearClassificationNotes
EDC Assessment2024Suspected endocrine disruptor
ECHA2019SVHC_EDCSVHC — endocrine disrupting properties (environment)
EU_REACH2014CoRAPCoRAP evaluation completed — ED ENV + ED HH unresolved

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 4-tert-butylphenol

  • Personal Care — essential oils, oral care, antiseptics
  • Food — spice flavoring (thymol, carvacrol)
  • 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 4-tert-Butylphenol:

  • Exposure reduction / process substitution
    Trade-offs: Removes 95-99% of dissolved contaminants including metals, PFAS, nitrates; wastes 2-4 gallons per gallon produced (improving with newer systems); removes beneficial minerals; $0.05-0.25/gallon; requires pre-treatment for longevity.
    Relative cost: 1.2-2×

Frequently asked questions

What products contain 4-tert-butylphenol?

4-tert-Butylphenol appears in: essential oils (Personal care); oral care (Personal care); spice flavoring (thymol, carvacrol) (Food); perfume (Fragrance); cologne (Fragrance).

Why do regulators disagree about 4-tert-butylphenol?

4-tert-Butylphenol has been classified by 3 agencies including EDC Assessment, ECHA, EU_REACH, 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 4-tert-Butylphenol in the body app

Look up products containing 4-tert-butylphenol, compare to alternatives, and explore the full data record.

Open in body View raw API data

Sources (1)
  1. PubChem Compound Database (2026) — database

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 →