A human eye is forever a moist place and because of this moisture, it is an attractive target for bacteria (they need moisture to grow), and foreign bodies (dust, etc.).
So, nature has made the eyes extremely sensitive to even the slightest disturbances (and provided blink reflex and tears for protection) because they are very delicate and can be damaged easily.
One of the things the eyes are sensitive to is the pH balance.
pH is short for potential of Hydrogen – A pH number measures, from 0 to 14, how acidic or alkaline something is – anything above 7 is alkaline and anything below 7 is acidic.
Tears and water have a pH of 7 and anything above or below 7 can be corrosive (the farther it is from 7 on either side, the more corrosive it is), and so, eyes need protection against these things.
But hair strands have a pH of 3.67, while the scalp has a pH of 5.5 (like the rest of the skin, which is slightly acidic for moisture retention and fighting germs).
Now, the closer the pH level of a product is to the pH level of the environment, in which it is to be used, the less reactive the product is to that environment (and therefore safer).
Ideally, therefore, the pH level of the shampoo for the hair strands should be 3.67 and the pH level of the shampoo for the scalp should But, obviously, you can’t use two different shampoos (one for hair and the other for scalp). be 5.5.
But, shampoos have a pH of anywhere between 3.5Shampoos with pH around 3.67 have been found to reduce fizz and provide improved hair combing and 9, and so, we have both acidic and alkaline shampoos available.
But very few adult shampoos have a pH level between 6 and 7 because, without the reactive chemicals, we can’t achieve cleanliness.
Baby shampoos, on the other hand, have a pH level between 6 and 7, which is easy on the eyes but not goodpH higher than 5.5 can increase the friction of the hair, which leads to frizz, hair breakage and general hair unmanageability for the hair and scalp, and not great at cleaning.
There are a few ways through which baby-shampoo companies achieve this pH level; higher dilution (more water and a lower concentration of cleaning chemicals) being one of them.
Also, most of them leave out cleaning agents such Sodium Lauryl Sulfate, which has a pH level of around 8 and is known to provide a rich lather and a high level of cleaning.
