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Moumoujus

BENZOPHENONE-2.

Questionable CAS 131-55-5 / FRAGRANCE, UV ABSORBER

A multifunctional, oil-soluble benzophenone derivative that serves as a broad-spectrum UV absorber and product stabilizer. It shields both the formulation and the skin by converting ultraviolet radiation into thermal energy while providing secondary benefits for pigment regulation.

Summary

UV Filter Light Stabilizer UV Absorber Tyrosinase Inhibitor

Science

Mechanism of Action

Operates primarily by absorbing UVA and UVB radiation, converting the energy into harmless heat to prevent photodegradation. On a biological level, it acts as a weak competitive inhibitor of tyrosinase (the rate-limiting enzyme in melanin synthesis), with an IC50 value of approximately 3.82 mM.

Research

Clinical Evidence

Medium confidence
Effective range 0.1–3.5%
Optimal

0.5%

Key findings

  1. 01 Human phototoxicity trials at concentrations up to 3.5% confirm the ingredient is non-phototoxic, though mild irritation may occur in select individuals (CIR 2021).
  2. 02 In vitro analysis (250 µM - 500 µM) identified competitive inhibition of the tyrosinase biosynthetic pathway (Garcia-Jimenez et al., 2017).
  3. 03 Dermal absorption studies (100 mg/kg) indicate systemic presence in the blood and brain following 4 weeks of application, though levels remained below the threshold for oxidative stress (Broniowska et al., 2019).

Transparency

Dusting Analysis

Commonly dusted
Min. effective
0.5%
Red flag below
0.1%

Benzophenone-2 is frequently used at concentrations below 0.1% solely to protect fragrance or color from fading in clear packaging. To achieve any functional tyrosinase inhibition or significant skin-level UV absorption, concentrations must be significantly higher, bordering on the regulatory limit.

The Formula

Formulation

Solubility
Oil
Optimal pH 6 – 7
0 7 14

Stability

Highly sensitive to ultraviolet exposure without stabilization; must be housed in opaque or dark-tinted packaging to prevent discoloration and loss of efficacy.

Synergies

  • Broad-spectrum SPF actives
  • Oil-based antioxidants

Conflicts

  • Strong oxidizing agents
  • High-heat manufacturing processes (>60°C)
  • Ultraviolet light (without secondary stabilizers)

Safety

Safety Profile

CIR Status
Safe as used
Max tested
3.5%
Sensitization risk Low

While the CIR maintains safety for current cosmetic use, the SCCS (2025) has raised concerns regarding genotoxicity and potential endocrine-disrupting activity, leading to a lack of safety confirmation in European assessments.

Your Skin

Skin Compatibility

Yes Normal
Yes Dry
Yes Oily
No Sensitive
Irritancy Low
Comedogenicity Low

Our Assessment

Verdict

Questionable

Though effective for preserving formula integrity, emerging data regarding endocrine disruption and systemic absorption makes it a sub-optimal choice for modern precision skincare.

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