pH and your hair

You must have heard about the pH scale a lot of time. We usually get a brief introduction on the topic in school. Today let’s see how important it is for maintaining the health of our hair.

pH ‘power of hydrogen’ is a value that measures how acidic or alkaline (or basic) a substance is. The pH scale ranges from 0 to 14. Water has a pH value of 7 which is neutral. 0-7 is acidic and 7-14 is alkaline.

A pH scale is a logarithmic scale, meaning a single pH value is ten times more acidic or alkaline than the next value. For example, pH 3 is ten times more acidic than pH 4 and 100 times (10 times 10) more acidic than pH 5. pH value is measured relative to water which is neutral (pH 7). When a substance is mixed with water then the mixture can become either acidic or alkaline.

Coming back to hair, our hair and skin are covered with a very thin layer called mantle(pH 4.5 to 5.5, so acidic) which consists of oil (sebum), salt and water (from sweat). Mantle is important to keep our hair and skin healthy and moisturized. The well balanced pH value of mantle keeps the hair cuticle closed and hence keep the moisture locked inside the hair. When the hair is exposed to alkaline solution, then the cuticle lifts up.

So it becomes very important to know the pH value of the products you use. Alkaline products makes the cuticles to lift up which leads to the moisture loss. Eventually it leads to frizzy, dull and brittle hair. It is best to use products which have the pH around the range of 4.5-5.5 (same as mantle). You might have noticed chemicals like citric acid, sodium hydroxide or triethanolamine towards the end of some of the ingredient lists. These are added to adjust the pH value of products.




Another harmful effect of using more alkaline products is fungal infection. Avoid using products having pH value greater than 7 as it strips the natural acidic sebum off your scalp that protects it from bacteria.

The products used in all chemical treatments like hair color, relaxer and perming are highly alkaline. During these treatments hair is first treated with alkaline solution to open up the cuticles and change the hair properties and then an acidic solution is applied to close down the cuticles. So if you color your hair, it is advised to use the slightly acidic products to retain the hair color for longer time.

Cuticles of curly hair tend to remain in open state. This is one of the reason that curly hair are naturally dry hair. So, keep a check on pH for curly hair. A pH range of 4 to 7 works well straight hair. But for curly hair pH should be more on acidic side (4-5.5).

Hair conditioner are meant to be acidic so after washing hair use leave-in conditioner on wet hair. We can use apple cider vinegar (ACV) or aloe vera juice mixed with water as a final rinse after the hair wash. Dilute the 2 tbsp of ACV with 2 cups of water and use it as a final rinse.

Most of the brands do not mention ‘pH balanced’ on their products. If you really want to know the pH value of these products, then you may use pH test paper strips which you can buy from ebay and Amazon.

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