Randomised Controlled Trial of an Antioxidant and Sunscreen Combination Cream for Reducing DNA Damage in Human Skin

Summary

This randomized, double-blind, vehicle-controlled clinical trial investigates whether daily use of an encapsulated SPF 50 formulation containing a multi-antioxidant complex provides greater mitochondrial DNA (mtDNA) protection in human facial skin compared with a vehicle-only cream.

Fifty-two healthy adults will be enrolled during the UK spring and randomized 1:1 to receive either the antioxidant-enriched SPF 50 or a matched vehicle (no SPF, no antioxidants). Participants will apply their assigned product once daily to the full face for 12 weeks under ambient ultraviolet (UV) and oxidative exposure.

Non-invasive cheek swabs collected at baseline and week 12 will be analyzed by blinded quantitative polymerase chain reaction (qPCR) to assess mtDNA integrity (ΔCt = Ct\_long - Ct\_short).

The primary objective is to determine whether the antioxidant-enriched SPF 50 reduces mtDNA damage compared with vehicle. Secondary objectives include comparing the proportion of "responders" showing reduced mtDNA damage (ΔCt \< 0) and evaluating within-participant change among habitual daily sunscreen users.

The trial aims to clarify whether adding antioxidants to high-SPF formulations can strengthen daily photoprotection by mitigating residual oxidative stress not fully blocked by UV filters alone.

Conditions

• Photoaging
• Photodamage
• Mitochondrial Damage
• Sunscreen
• Antioxidants
• Preventive Dermatology

Interventions

COMBINATION_PRODUCT

Antioxidant + Sunscreen Cream

A daily facial cream containing encapsulated broad-spectrum UV filters (SPF 50+, PA++++) combined with an antioxidant complex composed of Phytexcell Liquorice extract (Glycyrrhiza glabra), Resveratrol bioferment, and Vitamin E (tocopherol). The cream is applied once daily in the morning to the full face (approximately 2 mg/cm²) for 12 weeks.

COMBINATION_PRODUCT

Placebo cream

An identical-appearing vehicle cream without UV filters or antioxidant actives. The base formulation, texture, and packaging are identical to the active product. Applied once daily in the morning to the full face (approximately 2 mg/cm²) for 12 weeks.

Sponsors & Collaborators

• Guy's and St Thomas' NHS Foundation Trust

  collaborator OTHER

• Newcastle-upon-Tyne Hospitals NHS Trust

  collaborator OTHER

• Skin Analytics Limited

  collaborator INDUSTRY

• Klira Skin

  lead OTHER

Principal Investigators

• Emma Craythorne, Medicine MBChB · Guy's and St Thomas' NHS Foundation Trust

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-03-01

Primary Completion

2025-11-10

Completion

2025-11-10

Countries

• United Kingdom

Study Locations