A relationship between pH and enlarged pores?

The skin is the largest organ in our body. It's the first line of defense of our body against external influences. This protective function is made possible by the acidic pH of about 5.5 of the hydrophilic lipid membrane of the skin. This observation established by researcher Marchionini in 1929 has been confirmed by subsequent studies, notably those of Korting in 1992.

The hydrolipidic film on the surface of the skin is a complex emulsion primarily composed mainly of sweat and sebum. The acidic pH of the hydrolipidic film is an important factor in the homeostasis of the barrier, the integrity of the horny layer, and antibacterial defense. This is referred to as the acid mantle of the skin.

The skin's pH varies depending on both endogenous and exogenous factors. Among the endogenous factors, we can mention:

• Age : The skin pH of newborns is significantly higher than that of adults, with a value close to 7 (neutral pH), and this value decreases over time;

• Skin Zones : The pH of the skin is higher in certain areas (armpits, groin, intra-mammary area...). In the armpits, a higher pH leads to colonization by certain resident bacteria that produce odors, such as propionic bacteria and staphylococci. Therefore, deodorants containing citrates reduce the pH and inhibit bacterial activity;

• Skin Type : Indeed, teenagers with oily and acne-prone skin tend to have a more alkaline skin pH.

• Gender : Due to a higher sweat production, men have a more acidic skin pH than women.

• Skin Pigmentation : Studies have proven that darker skin tones have a more acidic skin pH than lighter skin tones. This is due to the higher presence of epidermal lipids, specifically fatty acids, which result in a lower pH and better integrity of the barrier function.