Normal skin has a pH between 5.4 and 5.9. Skin is covered by an acid mantle which is made up of sebum (free fatty acids) and sweat ( lactic acid and amino acid). This acid mantle has a pH between 4 and 5.5. The pH scale (potential hydrogen) runs from 1-14, one being most acidic and 14 being most basic. Water has a pH of 7 so it is neutral. Our skin, therefore, is acidic.
Soap is a base. The average pH of bar soaps is 9-10. Bars of soap are made from fat saponified by alkaline solution (oil and either NaOH or KOH). Below a pH of about 6, the emulsion often breaks down.
AHAVA Purifying Mud Soap (pH 5.5)
Without getting into a too complicated discussion of how soaps work, they basically surround dirt and oil and allow it to be washed away.
So, why does that matter?
People who have a skin pH on the higher end of normal are more susceptible to fungal infections. (An interesting note is that mosquitoes prefer more acidic skin, so people that get repeated fungal infections are not the people who are particularly bothered by mosquitoes).
Sebamed Cleansing Bar (pH 5.5)
Aveeno Moisturizing Bar With Colloidal Oatmeal for Dry Skin (pH 5.5)
Redkin for Men Acid Balanced Cleansing Bar (pH 5.5)
The effect of frequent washing with bar soap particularly is that the skin’s pH will be raised slightly and the skin will dry out, both of which encourage fungal infection.
If you are someone who gets fungal infections repeatedly, you might want to consider using a soap with a lower pH. Also, consider using a urea or lactic acid based cream after bathing to reduce the pH of your skin, particularly your feet.
Liquid Soaps
J.R. Watkins Liquid Hand Soap, Lemon (pH 5.5)
pHisoderm Down (dry skin) or Up (oily skin) (pH 5-6)
Also, a quick note on some common home remedies such as soaking feet in cider vinegar, peeing on your feet (ew…I know…but it’s out there), tea tree and oregano oils. These all act to acidify the skin.
Moisturizers
