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

NCT07301515 | Completed

• 1 other identifier: KLR-MITO-2025-01
• Study Type: interventional
• Target: 52
• Locations: 1 country
• Sites: 1

Brief 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

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

Keywords

Photoprotection; Broad-spectrum SPF 50; Encapsulated UV filters; Mitochondrial DNA; Oxidative stress; Facial skin; Vehicle-controlled trial; Randomized double-blind trial; Red algae extract; Resveratrol (bioferment); Vitamin E (tocopherol); Liquorice extract; Skin barrier

Outcome Measures

Primary Outcomes (1)

• Difference in Change in Mitochondrial DNA Damage (ΔCt) Between Active and Vehicle Creams Measured by Long-Amplicon Quantitative PCR

  Mitochondrial DNA (mtDNA) integrity will be assessed from non-invasive cheek swabs using long-amplicon quantitative polymerase chain reaction (qPCR). Two mtDNA fragments are amplified: a long fragment (damage-sensitive) and a short fragment (control for total DNA). ΔCt ("delta-Ct") = Ct\_long - Ct\_short, where higher values indicate greater mtDNA damage. For each participant, the change in ΔCt from baseline to Week 12 will be calculated. The primary outcome is the between-group difference in this change (Active minus Vehicle), adjusted for baseline values. Negative values denote reduced mtDNA damage with the antioxidant + SPF formulation. Laboratory staff and statisticians are blinded to allocation.

  Baseline to Week 12

Secondary Outcomes (4)

• Proportion of Participants With Reduced Mitochondrial DNA Damage (ΔCt < 0)

  Baseline to Week 12

• Change in Mitochondrial DNA Damage (ΔCt) From Baseline to Week 12 Among Habitual Daily Sunscreen Users - Active Arm

  Baseline to Week 12

• Change in Mitochondrial DNA Damage (ΔCt) From Baseline to Week 12 Among Habitual Daily Sunscreen Users - Vehicle Arm

  Baseline to Week 12

• Tolerability and Participant-Reported Cosmetic Acceptability

  Baseline to Week 12

Study Arms (2)

Antioxidant + Sunscreen Cream

EXPERIMENTAL

Participants apply 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 for 12 weeks.

Combination Product: Antioxidant + Sunscreen Cream

Vehicle-Only Cream

PLACEBO COMPARATOR

Participants apply an identical-appearing vehicle cream without UV filters, or antioxidants. The product base, texture, and packaging are identical to the active formulation. It is applied once daily in the morning to the full face for 12 weeks.

Combination Product: Placebo cream

Interventions

Placebo cream COMBINATION_PRODUCT

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.

Also known as: Vehicle cream

Vehicle-Only Cream

Antioxidant + Sunscreen Cream COMBINATION_PRODUCT

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.

Also known as: Proprietary Antioxidant + SPF Formulation

Antioxidant + Sunscreen Cream

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults aged 18-80 years
• Healthy facial skin with no active dermatologic disease
• Willing to apply the assigned product daily for 12 weeks
• Willing to avoid additional facial skincare products during the study period
• Able to attend baseline and week-12 visits for cheek-swab collection
• Willing to maintain stable medication and supplement use throughout the study
• Provided written informed consent

You may not qualify if:

• Active facial dermatologic disease or visible facial skin lesions
• Laser, peel, or energy-based facial treatment within the past 3 months
• Use of topical/systemic retinoids, antioxidants, or anti-inflammatory agents within 4 weeks of baseline
• Pregnancy or breastfeeding
• Recent acute illness or infection
• Planned travel to high-UV or sunny destinations during the study period
• Current smoker or regular e-cigarette user
• Participation in another clinical trial within the previous 30 days
• Known allergy or sensitivity to study-product ingredients
• Unstable medical conditions or medications known to affect mitochondrial function (e.g., recent changes in antibiotics, statins, or thyroid medication)

Sponsors & Collaborators

• Klira Skin: lead
• Newcastle-upon-Tyne Hospitals NHS Trust: collaborator
• Skin Analytics Limited: collaborator
• Guy's and St Thomas' NHS Foundation Trust: collaborator

Study Sites (1)

St John's Institute of Dermatology

London, United Kingdom

Location

MeSH Terms

Interventions

Antioxidants

Intervention Hierarchy (Ancestors)

Biological Factors; Molecular Mechanisms of Pharmacological Action; Pharmacologic Actions; Chemical Actions and Uses; Protective Agents; Physiological Effects of Drugs; Specialty Uses of Chemicals

Study Officials

• Emma Craythorne, Medicine MBChB

  Guy's and St Thomas' NHS Foundation Trust

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: This is a double-blind study with multiple levels of masking. Participants, care providers, investigators, and outcome assessors are blinded to treatment allocation. Study creams are dispensed in identical, opaque containers labeled only as "Formulation A" or "Formulation B." The randomization code is maintained by an independent administrator who is not involved in participant interaction, data collection, or analysis. Laboratory personnel and statisticians receive only anonymized, coded samples and datasets. Unblinding will occur only after database lock and completion of all primary analyses.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants are randomized in a parallel assignment to receive either an encapsulated SPF 50 plus multi-antioxidant cream (active) or a vehicle-only cream (comparator). A small, non-randomized observational group continues their usual skincare routine and/or sunscreen use to provide contextual background data. Randomization uses computer-generated block sequences with allocation concealment. Both participants and investigators are blinded to treatment assignment for the randomized arms.

Study Record Dates

• First Submitted: November 15, 2025
• First Posted: December 24, 2025
• Study Start: March 1, 2025
• Primary Completion: November 10, 2025
• Study Completion: November 10, 2025
• Last Updated: December 24, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will share
• Shared Documents: SAP, ICF
• Time Frame: Available within 12 months after primary completion and for 36 months thereafter.
• Access Criteria: Access will be granted upon reasonable written request accompanied by a brief proposal and analysis plan. Requests will be reviewed by the study steering team, and ethics approval or exemption may be required depending on local regulations.

Locations

GB (1)