Efficacy of Cosmetic Products in Preventing Pigmentation Induced by High Energy Visible Light (HEVL) [400-450nm]

Evaluation of the Efficacy of Anti-pigmentation Agents and/or Filters Under Part of Visible Light [400-450 nm] Exposures

The goal of this double-blind, randomized clinical trial is to evaluate the efficacy of anti-pigmentation cosmetic products in preventing skin pigmentation induced by High Energy Visible Light (HEVL) [400-450nm] in healthy volunteers (male and female, aged 18-60 years, Caucasian, phototypes III-IV).

The main questions it aims to answer are:

Can anti-pigmentation agents and/or HEV filters reduce HEV light-induced skin pigmentation, as measured by the Individual Typological Angle (Delta ITA°)? Can these products improve additional colorimetric parameters (Delta L*, a*, b*, Delta E) and clinical pigmentation and erythema scores (0-13 scale)? Are these formulations safe and well-tolerated under HEVL exposure? Researchers will compare seven cosmetic formulations (Products A to G) to an untreated exposed control zone to assess their ability to prevent HEVL-induced pigmentation.

Participants will:

Attend 36 visits over 7 weeks Receive standardized product applications (2 mg/cm²) on 7 test zones (3x3 cm) delineated on their back. One test zone will be not treated.

Be exposed to HEVL light [400-450nm] at 35 J/cm² over 4 consecutive days (Days 8-11) Undergo colorimetric measurements and clinical assessments of pigmentation and erythema at 13 time points

Inclusion Criteria:

1. Caucasian subjects
2. Male and female participants
3. Aged between 18 and 60 years old
4. Skin phototypes III-IV
5. Average ITA° on the back between 18° and 35° (± 2°) at screening and baseline/inclusion visit
6. Uniform skin color over the eight test zones (difference in ITA° between each zone ≤ 4°)
7. Untanned back (no UV exposure - natural or artificial - during the 2 months prior to inclusion)
8. No scar, spot, tattoo or excess hair on investigational zones
9. Subject having given written informed consent
10. Subjects able to read and understand study documents
11. Subjects with an official domicile
12. Subject covered by health insurance or social security
13. Female subjects of child-bearing potential using a safe method of contraception for at least 3 months prior to and throughout the study

Exclusion Criteria:

1. Pregnant, lactating, or planning to become pregnant during the study
2. Planned UV exposure (sunlight or sunbeds) of investigational zones throughout the study
3. Sunbed use or sun exposure of investigational zones within the 3 months prior to inclusion
4. Presence of sunburn (erythema) on the back
5. Dermatological disorders affecting investigational zones (naevi, freckles, excess hair, uneven skin tone, vitiligo, photodermatological problems)
6. History of skin cancer
7. History of abnormal response to sun
8. Presence of recent suntan or photo-test marks (per investigator opinion)
9. History of allergy, hypersensitivity, or serious reaction to any cosmetic product
10. Any concomitant medical condition that may interfere with the study (per investigator opinion)
11. Use of systemic medication for more than 5 consecutive days within the month prior to inclusion (e.g., steroids, antihistamines, antibiotics, vitamin A derivatives, psoralen)
12. Use of depigmenting, whitening or propigmenting topical treatments within the 3 months prior to inclusion
13. Physical treatment including laser or phototherapy (PUVA, IPL, PDT) within the past 6 months on investigational sites
14. Planned intensive sport (> 5 hours per week) or swimming during the study
15. Participation in another clinical study within 30 days prior to inclusion
16. Deprived of liberty by adjunction or official decision
17. Unable to be contacted by phone in case of emergency