Comedone is a primary lesion of acne vulgaris. It results from partial or complete obstruction of pilosebaceous duct and accumulation of sebum inside of duct. Isopropyl myristate and cocoa butter are not appropriate positive controls using the Mill and Kligman human model in Asian subjects, who have lower sensitivity to comedogenicity.


  • Study included 8 Asian females with prominent follicular orifices and prone to acne type skin on the upper back.
  • Isopropyl myristate, cocoa butter and petrolatum were prepared and 0.3 ml of each substances were applied on 16 cm2 area of upper back skin 3 times a week for 4 consecutive weeks. Applied skin was covered with a piece of non-absorbent cotton cloth.
  • An untreated negative control skin was covered by the patch materials with no substance.


  • The mean of casual sebum level on the forehead was higher than the upper back.
  • Compared to the baseline, the microcomedone activities of isopropyl myristate, cocoa butter, petrolatum, and non-treated control increased 63%, 47%, 55%, and 54%, respectively.
  • No significant differences in microcomedone activities between test substances were observed.
  • There were no statistical differences in adverse skin reaction potencies and irritation between two studied substances and the negative control.
Eunyoung Lee et al, Isopropyl Myristate and Cocoa Butter are not Appropriate Positive Controls for Comedogenicity Assay in Asian Subjects, Journal of Cosmetology & Trichology, 2015, 2:1

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