If you think back to high school chemistry class, you may recall that pH is an abbreviation for potential hydrogen. A pH number measures from 0 to14 how acidic or alkaline a liquid is -- anything above 7 is alkaline and anything below 7 is acid. Water has a pH level of 7 -- it's neutral, meaning it has the same amount of acids and alkalis, which balance each other out.
When you're thinking about liquids in terms of their pH levels, going up or down one number on the scale represents a tenfold change in the acidity or alkaline nature of a liquid. For example, the pH level of milk is around 6. Because the pH level of water is 7, milk is 10 times more acidic than water. Vinegar has a pH of about 3, making it 40 times more acidic than water [source: Carpi].
On the other end of the spectrum, milk of magnesia is a base with a pH of 10, which is why it's soothing to an acidic stomach. Lye has a pH of 13 and can dissolve sticky substances like fat. As you can see, substances at either end of the pH spectrum can be corrosive -- but if you combine these substances, they neutralize and create salt water. They balance because they're at opposite ends of the scale [source: Ophardt].
Now that you've had your general chemistry lesson, take a look at the next page to learn what pH-balanced means for your skin cleanser.
pH-Balance and Skin Cleansers
Because buzzwords like "pH-balanced" are common advertising tools in the health and beauty industry, it's easy to ignore them and purchase a product regardless of its pH. However, when it comes to skin cleansers, pH levels do make a difference.
Your skin has a pH level of about 5.5. Skin -- or at least the outermost layer of it -- is slightly acidic [source: University of California Newsroom]. The acidic layer helps your skin retain moisture and keeps germs out. To help maintain the skin's fatty protective layer, use a cleanser with a pH level similar to that of the skin itself. If you use a soap that's too alkaline, it will break up the acid in your skin, causing dryness.
The pH level of most skin cleansers is slightly higher than 5.5, so the cleanser can break down dirt and oil on your skin. However, soap -- especially bar soap -- typically has a pH level of 9 to 12, which is too high if you're trying to keep your skin moist. Cleansers with lower pH levels leave your skin intact instead of breaking down the fatty tissue [source: Draelos].
So, it must be important to use a skin cleanser that says it's pH-balanced, right? Yes and no. Most soap-free cleansers on the market today have balanced pH levels. Therefore, the words "pH-balanced" on a cleanser are more of a marketing ploy than anything else [source: Monroe].
Now that you're clear on what pH balanced means to you and your skin, you can be savvy in the skin care aisle. For more information on how pH affects your skin, take a look at the links on the following page.
Related HowStuffWorks Articles
- American Chemical Society. "pH Paper." Chemistry Comes Alive! 2002. (Accessed 8/27/09)http://jchemed.chem.wisc.edu/JCESOFT/CCA/CCA6/MAIN/1ChemLabMenu/Measuring/pH/pHpaper_menu/MENU.HTM
- Carpi, Anthony, Ph.D. "Acids and Bases: An Introduction." Visionlearning. 2003 (Accessed 8/27/09)http://www.visionlearning.com/library/module_viewer.php?mid=58
- University of California Newsroom. "Researchers Explain Origins of Skin's Acid Coating." 8/16/01. (Accessed 8/27/09)http://www.universityofcalifornia.edu/news/article/3502
- Ophardt, Charles E. "pH Scale." Virtual Chembook, Elmhurst College. 2003. (Accessed 8/27/09)http://www.elmhurst.edu/~chm/vchembook/184ph.html
- Draelos, Zoe Diana. "Cosmetic Formulation of Skin Care Products." 2006. (Accessed 8/27/09)http://books.google.com/books?id=MAshluUGiikC&pg=PA279&lpg=PA279&dq=ph+levels+in+skin+cleansers&source=bl&ots=3qD3f4IwbZ&sig=Be5qMihVEmr8fPe3TUx0xKZDRaI&hl=en&ei=wQeXSv2bPIfIMdDChYoD&sa=X&oi=book_result&ct=result&resnum=2#v=onepage&q=ph%20levels%20in%20skin%20cleansers&f=false
- Monroe, Val. "What Does pH Balanced Mean?" O: The Oprah Magazine. Nov. 2006. (Accessed 8/27/09)http://www.oprah.com/article/omagazine/val_200611_ph