The PH of a substance refers to the number of hydrogen ions it has. The scale ranges from 1-14, with 7 being neutral. The extremes of the scale are acidic (0 – 6.9) or alkaline (7.1-14). Why is PH relevant to hair care you ask? It is relevant because one of the characteristics of ethnic hair is a raised cuticle which coupled with a coiled structure lends a frizzed appearance. One of the hallmarks of acidity is its ability to cause the hair's cuticle to contract or lay down so substances with mild to moderate acidity are often desirable in our products. Black hair that is "PH balanced" has a smoothed cuticle which gives the hair a shiny smooth appearance. Black hair that is not balanced will have a raised cuticle which lends a rough, dull, frizzed appearance. Most shampoos and conditioners for ethnic hair are within the 3.5-5.5 range. An example of an extreme acidic treatment would be something like an apple cider vinegar rinse. Extreme acidity will cause the cuticle to contract or close and enhance smoothness and shine. As you can imagine you would not want your cuticle to be completely contracted permanently because this could slow aborption of nutrients and moisture, however for periodic clarification and shine this procedure is desirable. Conversely, for Caucasian hair which can be thin, flat and lifeless a slightly higher alkaline content can be effective in raising the cuticle and giving the hair a more volumized look. As a general rule of thumb, neutrality to moderate acidity is desirable for Black hair. Average water is a 7 which is exactly neutral. This makes water an excellent equalizer and very desirable as an overall moisturizer as it has no extreme effect on the cuticle and thus penetrates the hair shaft easily.