Glycylglycine decreases the size of conspicuous facial pores: Single-blinded half areas of face-applied study

Journal of Dermatology 2009; 36: 120 123
LETTER TO THE EDITOR

Dear Editor, Enlarged, or dilated facial pores are one of the most frequently encountered skin problems in women of all ages.

From our international survey, it has been revealed that more than half of women in their twenties and thirties complain of conspicuous pores.  Because so little had been known about their anatomical structure, facial pores were investigated.

The results indicated that pores were shown to form a cone-shaped hollow, which was rich in nucleated cells, an indication of parakeratosis. An investigation of the relationship between the degree of conspicuous pores and the condition of the skin indicated that women with abundant noticeably large pores showed high transepidermal water loss (TEWL) values, and high sebum content with significant amounts of unsaturated free fatty acids.1 A similar result of the relationship between the degree of visible pores and the amount of sebum has also been reported.3 Moreover, experimental application of oleic acid, an unsaturated fatty acid and the main component of human sebum,4 to the human skin promoted parakeratosis and increased TEWL values.1 Therefore, it was suggested that unsaturated fatty acids such as oleic acid may be responsible for the appearance of conspicuously enlarged pores. We then examined the effects of oleic acid on human keratinocytes to search for a substance that could inhibit such effects, and hopefully provide a way o improving the appearance of facial pores.

When oleic acid was added to keratinocytes, it was found that the concentration of intracellular calcium ions increased.5 Various kinds of antagonists were applied before the addition of oleic acid, and N-methyl D-aspartate (NMDA)-type glutamate receptor antagonists such as MK801 were found to specifically inhibit the buildup of calcium ions.