If you've taken a chemistry class in your day then you've probably covered the PH scale and its importance. However, many do not know that if you wish to maintain the vibrant color, shine and overall health of your hair it is essential to know how the PH levels in your shampoo and conditioner can affect it.

The basics:

PH or Potential Hydrogen is the amount of hydrogen in a solution that determines whether it is more acidic or alkaline. The PH scale ranges from 0-14 with 7 being "neutral", lower numbers (0-6) being more acidic, and higher number (8-14) more alkaline.

When applied to the hair, acidic products will close your hair cuticles and shrink the strand, while alkaline products will soften and swell the strand thus opening the cuticle. Hair falls naturally between 4.5-5.5 on the PH scale. The higher the PH level of your shampoo and conditioner, the harsher it is on your hair. The optimum PH level for your hair cleansing products is between 5-7 with water being neutral at 7.

Your hair consists of cuticles that resemble scales down its shaft. Water and alkaline base hair products causes these scales to open and expose the more sensitive interior of your hair shaft, the cortex thus releasing it's moisture. Moisture in the cortex helps keep hair flexible. If it escapes, hair appears dull, dry, and is prone to breakage and split ends.Acidic products closes the cuticle and protects the strand by helping retain moisture within the hair shaft.

Many common hair products and treatments fall on the alkaline spectrum with hair dye usually falling between 8-9 and relaxers between 13-14, severely damaging the hair. A PH shampoo and conditioner that reflects the hair's natural acidity of 4.5-5.5 is best for the hair. After treatments that will open the cuticle, more acidic products will make sure to lay those cuticles back down in order to maintain moisture in the hair and prevent further damage.

Unfortunately, many companies don't display the PH levels of their products. You can always purchase litmus paper (shown below), a type of paper that is used to test the acidity and alkalinity within products. Below is a list of some PH balanced brands that are healthier for the hair with levels ranging from 4-7: