The Importance Of pH In Hair Products


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By maintaining the correct pH balance as it affects the condition of hair cuticles, you can preserve the health and vitality of your hair. When the pH level inside hair deviates from the optimal pH range, it can cause issues with breakage, diminished appearance (shine), and frizz. So, next time you select a new hair product, it is important to understand how pH levels affect the hair and cuticle and to choose products that align with the natural pH of hair health. 

When we think of hair care, we jump to the importance of moisture, how shiny it is, and its strength. However, another important factor we must consider is the pH of our hair. 

In this guide, we will cover the overlooked topic of pH importance in hair and hair products, how to measure the pH in a range of hair products, and how to balance the pH of hair so you can maintain lovely-looking and healthy hair from your roots to tips!

What Is pH?

To understand the importance of hair pH, we must first understand what pH is and how it is distinctly related to hair. The pH scale runs from 0-14 with 7 being neutral. Values lower than 7 indicate an acidic substance and values greater than 7 indicate an alkaline or base. By understanding the pH scale, you can alter the pH of cosmetics like hair products when needed.

Hair that is considered healthy typically has a pH range between 4.5 and 5.5, making it slightly acidic. However, the pH level of a human’s scalp is around 5.5. The pH of the hair shaft (the part that is seen coming out of the scalp) has a pH of 3.67.

Why Is pH Important In Hair Products?

When shopping for hair products like shampoo, conditioner, or even hairspray, one thing you likely never thought of was the pH level inside that product. Yet, the pH is extremely important in hair products as the pH level has a profound impact on the overall appearance and health of your hair. 

Hair is extremely sensitive to the pH level of products that are applied to the hair’s surface. When a hair product that has a pH greater than 3.67 is applied to hair, it increases the static electricity resulting in repulsion between the hair strands. When the hair is rinsed with water, the hair is exposed to a neutral pH of 7. If the scales in the hair are weakened and slightly open, the hair can absorb the water, hydrating the strands and breaking the hydrogen bonds in the keratin molecule in the hair strand.

This is why wet hair becomes straight when we wash it, as it cannot regain its original shape. So, if you use the wrong shampoo for example when the hair is wet, it can enter the cuticle scales affecting the structure, and in severe cases, cracking the fiber axis which leads to breakage. This is why it is important to check the pH of hair products if possible, particularly those that are used when the hair cuticle is hydrated. 

What Happens To Hair If It Becomes Too Acidic?

As mentioned, the natural pH of hair is roughly between 4.5 and 5.5, yet when the pH of hair drops below this range, you may run into some issues. 

The outermost layer of your hair shaft is called the cuticle. When the pH drops below the ideal range, the cuticle can become damaged leading to hair feeling rough. It can also cause increased porosity and a weakened protective barrier, weakening your hair. 

Another issue is increased frizz and unwanted tangling. When hair is exposed to acidic conditions below the ideal pH range for hair, the hair fibers repel each other, making it more difficult to manage your hairstyle due to increased frizzing which in turn causes the hair to matt and tangle – ouch!

Now, everyone wants smooth, silky-looking hair, but when hair becomes too acidic you may experience dryness and brittle ends. This is because the low pH level can strip the hair follicles of their natural oils making it more prone to split ends and breakage. 

If you color your hair and your hair becomes exposed to acidic conditions, it can accelerate color fading, causing your hair to lose its vibrancy and more frequent use of hair colorants and dyes which are not only expensive but can also damage your hair if you need to use them more frequently. 

Finally, acidic products used on your hair and scalp can cause scalp irritation. This can lead to increased discomfort, itching, and the production of scalp conditions such as dandruff. 

What Happens To Hair If It Becomes Too Alkaline?

When the pH level exceeds 5.5 and becomes alkaline, the hair structure and appearance can also be problematic. 

Firstly the hair cuticle can be damaged when the hair becomes too alkaline. If this happens the outermost protective layer can swell, causing the cuticles to lift and increase friction between the fibers, leaving a roughened texture. This then contributes to tangling and exposes the hair to external environments making it more prone to damage. Alkaline conditions can also cause frizz due to the disruption of your hair fiber arrangement.

Just like when hair becomes too acidic, when the hair becomes too alkaline the hair lacks natural oils leading to brittleness, dryness, and breakage. This is due to high alkalinity weakening the protein bonding of the hair. Also, high alkalinity levels in hair lead to scalp issues mentioned above and color fading. 

The Ideal pH Range For Hair Products

There are copious amounts of hair products on the market today, therefore, to ensure optimal hair health, it is important to select hair products with pH levels that align with the natural pH level of our hair and scalp. 

Hair products should have a slightly acidic pH level to maintain the structure of the hair cuticle, promote hair health, and retain enough moisture to prevent dryness and breakage. While this is the ‘go-to’ method when selecting hair products, it is important to note that varying hair types may have different pH requirements. For example, people with naturally curly hair tend to benefit from hair products with a narrow pH range of 4-5.5 as their hair is typically more alkaline, whereas people with naturally straight hair typically benefit from hair products with a pH range between 4-7 because the hair is more acidic. This occurs as the natural scalp sebum has a low pH level and can travel faster in straight hair than curly hair (because of the twisting in the hair structure). Hence why people who have curlier hair are more prone to breakage and dry hair. 

This is why you should always purchase hair products that match accordingly with your hair type. 

Can Hair Products Negatively Affect Hair Health?

Absolutely! The products we select off the shelves can have a significant influence over the pH of our hair, and it isn’t always a good thing…

Next time you pick up a shampoo or conditioner bottle in the supermarket, turn it around and take a look at the ingredient list. You may be surprised to see that some contain dyes and bleach which tend to be alkaline. Some of these products can cause your hair to sway out of its healthy pH range. However, as you scan the ingredient list, you will likely come across hair oils which are usually beneficial for hair as they have a pH level within the spectrum of healthy hair.

Common Hair Products & Chemicals And Their pH Ranges

  • Hair Dyes (permanent): 9.5-10.5
  • Hair Dyes (semi-permanent): 7-9
  • Hairspray: 8-10
  • Bleaching & Highlights: 10-11
  • Perm Treatment (alkaline): 8-9
  • Perm Treatment (acidic): 4.5-6.8
  • Baking Soda: 8

It is important to avoid products with a pH level greater than 13, as these can cause extreme damage to the scalp, hair, and surrounding skin. 

How To Identify pH Levels In Hair Products?

Unfortunately for our hair’s health, hair product manufacturers don’t need to include the pH level of their product on the packaging. However, some brands choose to disclose this information on their website and product labels to put the customer at ease.

Other companies may display this information on their website under product descriptions or FAQs. Even though this information is displayed, often finding the correct pH may involve some trial and error for your specific hair type and also because individuals have varying scalp pH levels. 

If you are ever unsure which hair product is best for your hair type, always consult with a hairstylist/expert or a dermatologist who is trained to help customers select the best hair products. 

How To Measure The pH Of Hair Products & How To Adjust pH Levels

Measuring the pH of your hair is fairly simple, and all you need is a pH testing kit designed for hair. These are typically in pH test strips with a color chart to match the results.

  1. Firstly, wash your hair thoroughly.
  2. Secondly, dry your hair completely.
  3. Next, fill a container with distilled water, take a small section of your hair, and dip it into the container. 
  4. Over a few seconds, move your hair from side to side in the container.
  5. Once your hair is fully saturated in the distilled water, remove your hair from the container and place the pH strip against your wet hair
  6. Hold the pH test strip against the hair for a few seconds.
  7. Finally, remove the strip from your hair and use the color chart from the pH kit to compare the pH result – this will tell you if your hair is acidic, neutral, or alkaline.

Can You Use A pH Meter To Test The pH Of Hair Products?

Once you have tested the pH of your hair, you can go ahead and start testing the pH of your hair products to ensure that they align with your hair’s optimal range. 

Measuring the pH of hair products like shampoo or conditioner using a standard pH meter/sensor can pose a challenge due to the viscosity of the products and the presence of chemicals inside the liquid. Some challenges include inaccurate results, extended measurement times, and the clogging of the pH probe sensor junction. While it is not recommended to dilute the hair product with distilled water due to the reaction it can have with air, altering the pH and causing it to become ever so slightly acidic if your probe continuously clogs, you can mix the liquid hair product with distilled water ensuring that there is limited time between adding the water to the product to reduce inaccurate readings.

Alternatively, you can use pH testing strips by dipping the strip directly into the product. Once there is enough product on the strip, gently wipe the excess product off the strip to read the pH level. 

How To Adjust Hair pH Levels

Once you know the pH level of your hair, you can now make informed decisions regarding the products you will use. 

You always want to try and balance the hair product pH with the pH of your hair, as this will maintain your hair’s natural acidity. Always avoid products that contain sulfates because these are known to strip away the natural oils in the hair and scalp, plus sulfates can disrupt the natural pH balance. 

If you struggle to find products with a similar pH the good news is there are ways to adjust your hair’s pH. If your hair becomes too acidic, you can use apple cider vinegar. Mix 3 parts of water with 1 part of apple cider vinegar and pour it over your hair after shampooing. Allow the vinegar to sit in your hair for a couple of minutes before washing thoroughly. As apple cider vinegar is slightly acidic, it can help close your hair’s cuticles, leaving it looking healthier and smoother. 


Maintaining a healthy pH balance is important for your hair as the scalp protects the cuticles, resulting in shiny and robust hair. By actively selecting pH-balanced products and frequently checking the pH level of your hair, you won’t have to worry about dull or damaged hair.

If you would like to know more information on how pH can affect your hair, or what pH testing kits we have to offer, do not hesitate to reach out to the world-class team at Atlas Scientific.

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