Getting To Know Your Hair–pH & Hair

So far, we’ve discussed what healthy hair is and what three things are key in maintaining healthy hair – moisture, protein and pH. I’ve talked about the first two, moisture and protein and how to maintain the correct moisture/protein balance with regular wet testing. Today i’m continuing the ‘Getting To Know Your Hair’ series with a brief outline of what pH is and how it affects the health of our hair.

What is pH?



pH stands for ‘potential of hydrogen’ or ‘hydrogen strength’ and refers to the acidity or alkalinity of an aqueous (water based) solution relative to the concentration of hydrogen ions present. The level of pH is measured on a logarithmic scale of 0 – 14 with 0 being the most acidic and 14 being the most alkaline. In the middle we have pH 7 which is considered neutral as it has an equal balance of acidity and alkalinity. Water has a pH of 7 (hard water can measure pH 8!). pH 0 – 6.9 are acidic in nature and pH 7.1 – 14 are alkaline (base or caustic).



pH on a logarithmic scale is measured in multiples of 10 so every number on the scale is 10x more alkaline or acidic than the previous number. Example: pH 6 is 10x more acidic than pH 7, pH 5 is 10x more acidic than pH 6 and 100x (10×10) more acidic than pH 7. pH 8 is 10x more alkaline than pH 7 and pH 9 is 10x more alkaline than pH 8 and 100x (10×10) more alkaline than pH 7. It’s a little confusing i know, but it does help to know this (honestly).

What pH is Our Hair?

Our hair and skins pH measures between 4.0 – 5.5 so our hair is acidic in nature. In order to maintain optimal hair health we should try and keep our hair within this range.

How pH Affects Our Hair

pH greatly affects the way in which our hair looks, feels and behaves.


How Acidity Affects Our Hair

In it’s optimal pH range of 4.0 to 5.5 the cuticles of our hair lie flat against one another contributing to a smooth look and feel and allows light to bounce off well, giving our hair lovely shine or sheen. Closed cuticles protect the shaft from external damage and allows the strands to move around each other without causing damage. If we decrease the pH of our hair further, then the cuticles continue to tighten and tighten. Solutions or products with a pH lower than 3 will begin to corrode or eat away at the hair & scalp causing damage.

How Alkalinity Affects Our Hair

If we raise the pH of our hair above 5.5 the shaft begins to swell and the cuticles will begin to lift or open. Raised cuticles will allow more moisture into our hair but will also allow more moisture out. Lifted cuticles expose the hairs cortex and provides limited protection. Hair in this state is considered weak and susceptible to further damage. Lifted cuticles cause the hair to look dull and rough and each strand can tangle on the next causing more damage to the cuticle layer. The higher the pH the more our hair swells and our cuticles lift incurring more and more damage. Solutions or products with a pH of 10 or more will begin to dissolve the hair and scalp causing damage. Permanent hair dyes and relaxers are extremely alkaline (pH values between 10 and 13) and work by lifting the cuticles so the chemicals can deposit onto and alter the cortex/main structure of the hair.  Highly alkaline solutions weaken the disulfide bonds in the hair and can alter it’s structure permanently.

Maintaining Healthy Hair With pH

Our goal here is to maintain the hairs optimal pH range of between 4.0 and 5.5 and thus keep it nice and healthy. All products containing water have a pH value and it’s important that our water based products such as shampoos, conditioners, leave-ins and moisturisers be within this range. Remember, water is 100 – 1000 times more alkaline than our hair so even a quick warm water rinse will cause the cuticles to lift slightly. If we dry our hair and apply oil or butter straight onto our hair after rinsing with warm water, the cuticles will remain open causing a slight feel of roughness and less sheen or shine. We should always try to restore or rebalance our hairs pH. It’s important, then, to use a water based, pH balanced (acidic) leave-in or moisturiser after washing our hair to bring the pH back down and close the cuticles before sealing with an oil or butter. A final rinse of diluted ACV (Apple Cider Vinegar) also serves this purpose. Aloe Vera is also a great ingredient choice for hair moisturisers and spritzes as its pH value is around 4. This way we ensure our cuticles are closed, that moisture is retained well and our hair is stronger and less susceptible to damage.

The last post in this series will be on porosity and how it affects our hair, including how to correct any porosity issues.

Until next time!