Body & Beauty / Compounds / Diisobutyl phthalate

Diisobutyl phthalate on your skin: a safety profile

Moderate risk

(People-specific data is limited; this page draws from human adult context.) Diisobutyl phthalate (DIBP; CAS 84-69-5) is a reproductive/developmental toxicant of regulatory concern — included in EFSA's 2019 cumulative antiandrogenic phthalate group TDI (50 μg/kg bw/day for DEHP + DBP + BBP + DIBP combined). For adults, reproductive toxicity concern centers on male reproductive system effects at sufficient cumulative phthalate exposure. DIBP is restricted under EU REACH (Annex XVII) as an SVHC (Substance of Very High Concern) for reproductive toxicity. No carcinogenicity classification from IARC, US EPA, or EFSA. Metabolism produces mono-isobutyl phthalate (MiBP), the primary biomarker in urine — MiBP is detected in human populations globally through food contact material migration, dust ingestion, and industrial exposure. At current typical background exposure levels, most adults have cumulative phthalate intakes near or below the EFSA TDI, but high-exposure subgroups (occupational, certain dietary patterns, high personal care product use) may exceed it. Minimizing unnecessary exposure to DIBP-containing products is prudent.

What is diisobutyl phthalate?

The IUPAC name is bis(2-methylpropyl) benzene-1,2-dicarboxylate.

Also known as: bis(2-methylpropyl) benzene-1,2-dicarboxylate, DIBP, Isobutyl phthalate, Palatinol IC.

IUPAC name
bis(2-methylpropyl) benzene-1,2-dicarboxylate
CAS number
84-69-5
Molecular formula
C16H22O4
Molecular weight
278.34 g/mol
SMILES
CC(C)COC(=O)C1=CC=CC=C1C(=O)OCC(C)C
PubChem CID
6782

Risk for people

Moderate risk

Diisobutyl phthalate (DIBP; CAS 84-69-5) is a reproductive/developmental toxicant of regulatory concern — included in EFSA's 2019 cumulative antiandrogenic phthalate group TDI (50 μg/kg bw/day for DEHP + DBP + BBP + DIBP combined). For adults, reproductive toxicity concern centers on male reproductive system effects at sufficient cumulative phthalate exposure. DIBP is restricted under EU REACH (Annex XVII) as an SVHC (Substance of Very High Concern) for reproductive toxicity. No carcinogenicity classification from IARC, US EPA, or EFSA. Metabolism produces mono-isobutyl phthalate (MiBP), the primary biomarker in urine — MiBP is detected in human populations globally through food contact material migration, dust ingestion, and industrial exposure. At current typical background exposure levels, most adults have cumulative phthalate intakes near or below the EFSA TDI, but high-exposure subgroups (occupational, certain dietary patterns, high personal care product use) may exceed it. Minimizing unnecessary exposure to DIBP-containing products is prudent.

Regulatory consensus

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

AgencyYearClassificationNotes
EFSA (cumulative phthalate group TDI assessment, 2019)2019no separate carcinogenicity classification; included in EFSA 2019 cumulative phthalate group TDI of 50 μg/kg bw/day for combined DEHP, DBP, BBP, DIBP based on antiandrogenic reproductive/developmental toxicity
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 0 positive / 4 negative reports)
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 0 positive / 4 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 diisobutyl phthalate

  • Consumer Products — Plastic bottles and containers, Food packaging, Plastic toys and household items
  • Drinking Water — Leaching from plastic pipes, Migration from bottled water containers
  • Indoor Environments — Off-gassing from plastic furniture, Degradation of plastic products
  • 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 Diisobutyl phthalate:

  • 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
  • DINCH
    Relative cost: 1.2-2×
  • Citrate esters
    Relative cost: 1.2-2×

Frequently asked questions

What products contain diisobutyl phthalate?

Diisobutyl phthalate appears in: Plastic bottles and containers (Consumer products); Food packaging (Consumer products); Leaching from plastic pipes (Drinking water); Migration from bottled water containers (Drinking water); Off-gassing from plastic furniture (Indoor environments).

Why do regulators disagree about diisobutyl phthalate?

Diisobutyl phthalate has been classified by 3 agencies including EFSA (cumulative phthalate group TDI assessment, 2019), 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 Diisobutyl phthalate in the body app

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

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Sources (2)
  1. EFSA 2019 Cumulative Phthalate Group TDI 50 μg/kg bw/day: DEHP + DBP + BBP + DIBP Antiandrogenic Endpoint; DIBP Relative Potency Factor 1; Reproductive Developmental Toxicity; Not Carcinogenicity Assessment (2019) — regulatory
  2. EU REACH Annex XVII Entry 51 DIBP Restriction: SVHC Reproductive Toxicant Category 1B; Toys Childcare Articles >0.1% Concentration Limit; Antiandrogenic Phthalate Syndrome (2015) — 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 →