Body & Beauty / Compounds / Avobenzone

Avobenzone on your skin: a safety profile

Low risk

(People-specific data is limited; this page draws from human adult context.) Avobenzone (Parsol 1789; CAS 70356-09-1) is the primary UV-A filter in US broad-spectrum sunscreens and has a long history of use (approved since 1988 in the US). No carcinogenicity classification by IARC, US EPA, or any major regulatory body. FDA's Category III designation (2019 proposed rule) reflects a regulatory process requiring additional data — not a determination of harm. Systemic absorption is confirmed (blood concentrations exceed FDA's 0.5 ng/mL threshold in pharmacokinetic studies), and in vitro estrogenic activity has been reported, but the clinical significance at real-world use concentrations is uncertain and the subject of ongoing research. The overall benefit-risk calculus strongly favors sunscreen use: UV radiation is a Group 1 IARC carcinogen (melanoma, squamous cell carcinoma causation firmly established), and broad-spectrum UV-A protection from avobenzone demonstrably reduces UV-A-induced skin cancer risk. Major dermatological organizations (American Academy of Dermatology, British Association of Dermatologists) continue to recommend avobenzone-containing sunscreens pending full FDA GRASE determination.

What is avobenzone?

The IUPAC name is 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione.

Also known as: 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione, Parsol 1789, Butyl methoxydibenzoylmethane, Escalol 517.

IUPAC name
1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione
CAS number
70356-09-1
Molecular formula
C20H22O3
Molecular weight
310.4 g/mol
SMILES
CC(C)(C)C1=CC=C(C=C1)C(=O)CC(=O)C2=CC=C(C=C2)OC
PubChem CID
51040

Risk for people

Low risk

Avobenzone (Parsol 1789; CAS 70356-09-1) is the primary UV-A filter in US broad-spectrum sunscreens and has a long history of use (approved since 1988 in the US). No carcinogenicity classification by IARC, US EPA, or any major regulatory body. FDA's Category III designation (2019 proposed rule) reflects a regulatory process requiring additional data — not a determination of harm. Systemic absorption is confirmed (blood concentrations exceed FDA's 0.5 ng/mL threshold in pharmacokinetic studies), and in vitro estrogenic activity has been reported, but the clinical significance at real-world use concentrations is uncertain and the subject of ongoing research. The overall benefit-risk calculus strongly favors sunscreen use: UV radiation is a Group 1 IARC carcinogen (melanoma, squamous cell carcinoma causation firmly established), and broad-spectrum UV-A protection from avobenzone demonstrably reduces UV-A-induced skin cancer risk. Major dermatological organizations (American Academy of Dermatology, British Association of Dermatologists) continue to recommend avobenzone-containing sunscreens pending full FDA GRASE determination.

Regulatory consensus

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

AgencyYearClassificationNotes
WHO2021no carcinogenicity classification; UV-A sunscreen filter without recognized carcinogenicity assessment; FDA Category III (insufficient data for GRASE determination pending additional safety studies)
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 0 positive / 3 negative reports)
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 0 positive / 3 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 avobenzone

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles
  • Personal Care — sunscreen, moisturizer with SPF, foundation, lip balm

Safer alternatives

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

  • Fragrance-free formulations
    Trade-offs: Consumer preference for scented products
    Relative cost: 1.2-2×
  • Essential oil-based fragrances (with disclosure)
    Trade-offs: Natural does not mean safe — many essential oils are skin sensitizers
    Relative cost: 2-5×

Frequently asked questions

What products contain avobenzone?

Avobenzone appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); sunscreen (Personal care).

Why do regulators disagree about avobenzone?

Avobenzone has been classified by 3 agencies including WHO, 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 Avobenzone in the body app

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

Open in body View raw API data

Sources (2)
  1. FDA 2019 Proposed OTC Sunscreen Rule: Avobenzone Category III Insufficient Data GRASE; Systemic Absorption >0.5 ng/mL Threshold; Additional Safety Studies Required; Endocrine Estrogenic Activity In Vitro (2019) — regulatory
  2. Hawaii Act 104 Reef Protection Sunscreen 2021: Oxybenzone Octinoxate Banned; Avobenzone Photodegradation Products; Coral Bleaching Aquatic Toxicity; UV Filter Environmental Fate Shallow Marine (2021) — 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 →