Evaluation of the protection of sunscreen products against long wavelength ultraviolet A1 and visible light-induced biological effects

Authors

Nneamaka Ezekwe, Henry Ford HealthFollow
Aunna Pourang, Henry Ford HealthFollow
Alexis B. Lyons, Henry Ford HealthFollow
Shanthi Narla, Henry Ford HealthFollow
Amruth Atyam, Henry Ford Health
Sheeren Zia, Henry Ford HealthFollow
Ben J. Friedman, Henry Ford HealthFollow
Iltefat H. Hamzavi, Henry Ford HealthFollow
Henry W. Lim, Henry Ford HealthFollow
Indermeet Kohli, Henry Ford HealthFollow

Recommended Citation

Ezekwe N, Pourang A, Lyons AB, Narla S, Atyam A, Zia S, Friedman BJ, Hamzavi IH, Lim HW, and Kohli I. Evaluation of the protection of sunscreen products against long wavelength ultraviolet A1 and visible light-induced biological effects. Photodermatol Photoimmunol Photomed 2023.

Document Type

Article

Publication Date

1-1-2024

Publication Title

Photodermatology, photoimmunology & photomedicine

Abstract

BACKGROUND: Long wavelength ultraviolet-A1 in combination with visible light induces hyperpigmentation, particularly in dark-skin phototypes. This study evaluated the efficacy of four sunscreen formulations in protecting against VL + UVA1 (370-700 nm).

METHODS: The test products (A-D) were applied to the back of 12 volunteers, then irradiated with 320 J/cm(2) VL + UVA1 (3.5% UVA1 [370-400 nm]). Immediately after irradiation, and at Days 1, 7, and 14, erythema and pigmentation were assessed by investigator global assessment (IGA), colorimetry (Δa* and ΔITA) and diffuse reflectance spectroscopy (DRS)-measured relative dyschromia (area under the curve AUC). Control areas were irradiated without sunscreen.

RESULTS: Product D, containing titanium dioxide 11%, iron oxides 1%, and antioxidants, provided the highest and most consistent protection. Compared with unprotected irradiated control, it had statistically significantly less erythema on IGA, DRS (Δoxyhemoglobin), and colorimetry (Δa*) at Day 0; less pigmentation on IGA at all time points, on DRS (relative dyschromia) at Days 7 and 14, and on colorimetry (ΔITA) at Day 0. Product B, containing zinc oxide 12% plus organic UV filters, iron oxides 4%, and antioxidants, also showed some efficacy.

CONCLUSION: Of the sunscreens tested, the tinted products provided better protection against VL + UVA1 than the non-tinted products. Since the product with 1% iron oxides was superior to the product with 4% iron oxides, further studies are needed to evaluate whether iron oxide content correlates with better protection.

Medical Subject Headings

Humans; Sunscreening Agents; Ultraviolet Rays; Light; Erythema; Oxides; Iron; Immunoglobulin A; Skin

PubMed ID

38069506

ePublication

ePub ahead of print

Volume

40

Issue

1

First Page

12937

Last Page

12937