A systematic review of 11 articles and 18 cosmetic-whitening ingredients derived MTT IC50 values and compared them with cLogP. The overall positive relationship was modest (R²=0.3263), and seven ingredients had IC50 below 50 micrograms/mL. Heterogeneous cell lines, media, exposure times and assays prevent this from being a human safety ranking.
Key findings
- cLogP explained 32.63% of overall IC50 variation and 35.35% among lipophilic ingredients. Hydrophilic compounds showed essentially no association (R²=0.00021, p=0.8537). Seven of 18 fell below the authors' 50 micrograms/mL threshold, while hydroquinone was explicitly identified on the ASEAN prohibited list.
Why this matters globally
The review identifies pre- and post-market safety gaps and supports standardised melanocyte-toxicity evidence rather than relying only on manufacturer assurance.
Thai researcher contribution
A Walailak University researcher contributed evidence directly relevant to the ASEAN Cosmetic Directive and regional regulation.
Limitations to consider
Only 11 heterogeneous studies were available. Retrospective IC50 derivation may be unstable, risk-of-bias synthesis and human-skin exposure data were absent, and moderate R² does not support ingredient-level prediction from cLogP.