Drometrizole trisiloxane on your skin: a safety profile

What is drometrizole trisiloxane?

The IUPAC name is 2-benzotriazol-2-yl-4,6-bis(1,1-dimethylethyl)phenol trisiloxane.

Also known as: 2-benzotriazol-2-yl-4,6-bis(1,1-dimethylethyl)phenol trisiloxane, Mexoryl XL, benzotriazole trisiloxane UV absorber.

IUPAC name

2-benzotriazol-2-yl-4,6-bis(1,1-dimethylethyl)phenol trisiloxane

CAS number

155633-54-8

Molecular formula

C36H56O4Si3

Molecular weight

653.11 g/mol

SMILES

C1=CC(=CC=C1NCC(=O)N)[As](=O)(O)[O-].[Na+]

PubChem CID

6433202

Regulatory consensus

2 regulatory and scientific bodies have classified Drometrizole trisiloxane. The classifications differ — that's the data.

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 drometrizole trisiloxane

• water_resistant_sunscreen
• sports_sunscreen
• premium_sunscreen
• facial_sunscreen

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Drometrizole trisiloxane:

• Mineral UV filters (zinc oxide, titanium dioxide) — no systemic absorption
  Trade-offs: Alternative approach; specific tradeoffs depend on application context, scale, and regulatory requirements. Full hazard assessment of alternative recommended before adoption to avoid regrettable substitution.
  Relative cost: 1.2-2×
• Newer-generation organic filters with lower skin penetration (e.g., bisoctrizole)
  Trade-offs: Alternative approach; specific tradeoffs depend on application context, scale, and regulatory requirements. Full hazard assessment of alternative recommended before adoption to avoid regrettable substitution.
  Relative cost: 2-5× conventional
• UPF-rated clothing and physical sun protection
  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