Myth: ". The typical pH balance of hair is around 4.5-5.0" "There are a number of conditions that can indicate the pH of your hair. It is important to establish a general pH before you can balance it to the healthy level"
Hair DOES NOT HAVE A pH at ALL! Only Aqueous solutions have a pH and hair is a solid. Hair is a solid material with three distinct layers.
The center is called the medulla and it is usually an empty space. Next is the cortex that is coils of keratin protein molecules plus melanin which gives our hair the colour. The outer layer is the cuticle that has overlapping scales and it protects the cortex and center. ("a thick protective cover consisting of six to eight layers of flat overlapping scale-like structures called cuticle or scales which consists of high sulfur KAPs, keratin proteins and structural lipids." Chemical and Physical Behavior of Human Hair, Clarence R. Robbins) None of these things is living, there are no nerves or growth. The follicle that is attached to your scalp is alive with nerves and new growth.
Below you can read the definition of what pH is, it is a potential for a hydrogen molecule to enter an aqueous solution. It does not have a unit of measure. pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water
“pH” is an abbreviation for “potential hydrogen” and is a scale used for ranking the relative acidity or alkalinity of a liquid solution. The precise mathematical definition of pH is the negative logarithmic value of hydrogen ion (H+) concentration in the solution.
pH = - log [H+]
Hair does have a net charge that we can measure because it contains protein. The building blocks of proteins, peptides, all have a pH value at which they are neither positively nor negatively charged. A protein at its isoelectric point has zero net charge. That point or most hair, on average, is when it is in a solution with a pH of 3.67. When in a solution with a pH above 3.67 hair will have a net negative charge. The surface of hair has a net negative charge at all pH values above its isoelectric point. This is where the internet determined hair to have a pH. It does not. It has an isoelectric point. After you rinse your hair with water it will dry and return to it's isoelectric point. After you swim in the ocean... your hair will dry and return to it's isoelectric point.
Source: Springer; 5th ed. 2012 edition (Feb. 24 2012)
Above is the gorgeous hair of a 48 year old customer that has used my saponified shampoo for years. She washes her hair every three days and allows it to air dry. The hair is not stressed, falling out or broken. The "mantle" is not destroyed. The scalp is healthy. It is easy to comb through silky clean hair! How can this be? Detergent manufacturers would like us to be afraid to make and sell natural products. They would like even more for customers to be afraid to even try them. Personally I believe they feel threatened by the plastic free movement. They don't know what to do when their plastic bottles are gone!
TRUTH: Every human has an acidic mantle, or microflora, and we create it naturally. I just measured the pH of my moist face and it is 5.0. (I wash with my own tea tree face soap by the way)
Wikipedia description: The acid mantle is a very fine, slightly acidic film on the surface of human skin acting as a barrier to bacteria, viruses and other potential contaminants that might penetrate the skin.[1] Sebum is secreted by the sebaceous gland and when mixed with sweat becomes the acid mantle. The pH of the skin is between 4.5 and 6.2, slightly acidic.[2][3] Since blood is slightly alkaline (7.4), pathogenic bacteria that become adapted to the pH of the skin and are able to reach internal tissues will encounter an environment to which they are less well adapted. This combination of acidic exterior and alkaline interior is one of the body's non-specific host defenses against bacterial pathogens.
A very good reference
http://www.sebamed.com/fileadmin/user_upload/pdf/Studien/Saeuremantelkonzept/1.05.pdf
Now back to the discussion of hair having a critical pH, and whether or not we should all be afraid of saponified shampoo:
Saponified Shampoo will create a lather that has a pH of around 9.0. It can't get any lower than that. Since the bar is solid... it doesn't have a pH. It isn't aqueous. The lather does though since it is a measurable combination of air bubbles, soap particles and water.
For comparison the Ocean has a pH of 8.2. Tap water will have a pH of 7, swimming pools will be 7.4 to 7.6.
The directions on a shampoo bar are not to take that bar and rub it on your dry head. The directions are : Hold shampoo bar in one hand and apply it directly to wet hair, starting at your scalp. Work suds through the rest of your hair. You can also lather up the bar in your hands and then apply lather to your hair instead of the shampoo bar.
1) In a shower or bath wet your hair. Now your hair, of no pH, is surrounded by water of a pH of 7.
2) either apply the bar to your wet hair, or create lather in your hands and apply that to your hair. Now your hair is surrounded by water that has a pH of 8 - 8.5. You diluted the lather because your hair was already wet. This step will take about 20 - 30 seconds.
3) Now rinse well. We are back to having hair and scalp at a pH of 7.0. You will only have a scalp with a higher pH if you didn't rinse out the lather. Why wouldn't you rinse?
The directions on a detergent/syndet bar are exactly the same as the saponified bar. Your hair and scalp will be covered in water with a pH of 7.
That is why my family and customers do not have bad results using a saponified bar. My scalp is as healthy as the rest of my skin. Within 2 hours of bathing my body naturally sweats and "repairs" my mantle and we are back to the acidic layer we had before the bath or shower. That is how God made us. Why would God have given us hair that is so sensitive that I can't even wash it?
For scientific proof the article referenced above ( MSchmid MH, Korting HC (1995). "The concept of the acid mantle of the skin: its relevance for the choice of skin cleansers" (PDF). Dermatology. 191 (4): 276–80. ) found that using soap or syndet didn't matter, in 2 hours the pH of everyone's skin was acidic again.
Note that the soap users in this study had slightly higher propionibacteria counts after two weeks. Propionibacteria is natural, we all have creatures living on our skin. (don't freak out) However also note that in that study they asked participants to wash twice a day and they provide no details on the soap they used, rinsing or drying techniques. Did they coincidentally dry off more with towels than the others? How was any of this controlled?
I don't know anyone who washes twice a day. Maybe if you work out twice a day? Then you're a person sweating up a storm introducing a layer of sweat with a pH of 4.5 - 7.0.
Note: Demodex hates Tea Tree Oil.
