Multi-phototype clinical study
126 women. 3 continents. 90 days.
Our first independent clinical study was conducted simultaneously in Seoul, Mumbai and Lagos to validate our formulas on three major Fitzpatrick phototypes. No marketing selfies. No self-assessments. Here are the results.
On the ground
Three cities, three climates, three ethnicities.
We didn't test in a comfortable lab. Each protocol was conducted in the country of origin of the studied skin, with real climate conditions: urban pollution of Seoul, humid monsoon of Mumbai, dry harmattan of Lagos.
37.5°N · 127.0°E
Seoul
Republic of Korea
Yonsei University Skin Research Center
Dr. Min-Jun Park
19.0°N · 72.8°E
Mumbai
India
KEM Hospital Dermatology Dept.
Dr. Priya Iyer
6.5°N · 3.4°E
Lagos
Nigeria
Lagos University Teaching Hospital
Dr. Adaeze Okonkwo
Protocol
ICH-GCP, the pharmaceutical industry standard.
No selfies. No subjective self-assessments. Objective clinical measurements via calibrated instruments, by certified dermatologists.
01
Double blinding
Neither participants nor evaluators knew who received the test product or placebo. Observation bias reduced to zero.
02
Instrumental measurements
Corneometer CM825 (corneal hydration), Mexameter MX18 (melanin + erythema), Visia CR (texture + pores + pigmentation), Cutometer MPA580 (elasticity).
03
Placebo control
Control group receiving a vehicle without active. Each positive effect is compared to control to exclude psychological and environmental factors.
04
Time points
Day 0, day 14, day 30, day 90. Additional assessments at 6 and 12 months to verify effect persistence.
Before / After
Three skins, three transformations.
Photographs in standardized studio light (D65), same angle, same distance, same hour. No retouching. Select the phototype.
Day 0
Day 14
Day 30
Measured results
Performance across five clinical KPIs.
Average scores at 90 days for each phototype, compared to baseline. The further the gold polygon extends, the better the performance.
Séoul
Mumbai
Lagos
Principal investigators
The three hands that led the study.
Selected for their recognized expertise in ethnic dermatology of their region. None is compensated by The Secret of Joseon — their indemnification is strictly academic.
Dr. Min-Jun Park
Principal Investigator · Seoul
Yonsei University Skin Research Center
15 years · cosmetic dermatology
"Modern Korean cosmetics know how to formulate. What was missing was proving efficacy on ethnicities other than ours. This study does that."
Dr. Priya Iyer
Principal Investigator · Mumbai
KEM Hospital Dermatology Department
12 years · post-inflammatory hyperpigmentation
"Hyperpigmentation is my patients' primary concern. The niacinamides and tranexamic acid in this formula give results I had not seen before."
Dr. Adaeze Okonkwo
Principal Investigator · Lagos
Lagos University Teaching Hospital
11 years · West African skin types
"Too many brands formulate for light skin then 'adapt' for darker skin. Here we have a formula designed multi-phototype from the start. The difference is notable."
Read the full study
The original study, 42 pages, open access.
Detailed protocol, raw statistics, per-subject measurements, placebo comparisons. No marketing in the PDF — just the numbers.
Download the study (PDF · 4.2 MB)