The Importance of pH in Shampoo for Hair and Scalp Health

The pH value of shampoo in water is a crucial factor to consider for DIY users who want to maintain their hair and scalp health while being environmentally friendly. Understanding the impact of pH on hair and scalp can help you make informed decisions when choosing or creating your own shampoo.

Understanding the pH Scale

The pH scale ranges from 0 to 14, with 7 being neutral. Values below 7 are considered acidic, while values above 7 are alkaline. The ideal pH for hair and scalp health is around 5.5, which is slightly acidic.

The Impact of Shampoo pH on Hair and Scalp

PH of shampoo in waterImage source: picryl

The pH value of shampoo can affect the hair fiber surface’s electrical charge and friction between fibers. Alkaline shampoos (pH > 5.5) may increase negative electrical charge and friction, leading to cuticle damage, hair breakage, and frizz. On the other hand, lower pH shampoos (pH ≤ 5.5) may cause less frizz by generating less negative static electricity on the fiber surface.

Unfortunately, many popular brand shampoos have a pH higher than the hair shaft pH of 3.6 and even higher than the scalp pH of 5.5. This is because there is no standardized pH value for hair shampoo, and the pH level is not mandatory to be printed on the product labels or specified among the product formulation. However, studies have shown that using shampoo with a pH higher than 5.5 may increase friction and cause frizz, hair breakage, and enhance hair tangling.

Balancing the pH of Shampoo in Water

To balance the pH of shampoo in water, a conditioner of low-pH should be applied after shampooing to neutralize electrostatic forces, eliminate the frizz effect, and seal cuticle scales. If the conditioner is not recommended by a dermatologist, it is necessary to choose a shampoo with a pH lower than 5.5.

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DIY Shampoo and pH Considerations

When it comes to DIY shampoo, it is crucial to consider the pH value of the ingredients used. For example, baking soda has a pH of around 9, which is too alkaline for hair and scalp health. Instead, consider using ingredients with a pH closer to 5.5, such as apple cider vinegar or lemon juice, in small quantities to balance the pH of the shampoo.

Environmental Impact of Shampoo in Water

Regarding the environmental impact of shampoo in water, it is essential to consider the chemicals and plastic waste associated with shampoo bottles. Many shampoos contain harmful chemicals that can harm both aquatic life and the animals that drink from these bodies of water. Additionally, shampoo bottles are often only partially or totally unrecyclable, causing a tremendous amount of waste and damage to our planet.

To reduce the environmental impact of shampoo in water, consider using solid shampoo bars, which are concentrated, active, plant-based ingredients without water. This not only reduces plastic waste but also saves money in the long run, as solid shampoo bars last for between 60 – 80 washes.


In summary, maintaining the pH value of shampoo in water is crucial for hair and scalp health. Choosing shampoos with a pH lower than 5.5, using low-pH conditioners, and considering DIY shampoo with balanced pH ingredients can help maintain healthy hair and scalp. Additionally, reducing plastic waste and harmful chemicals associated with shampoo bottles can help protect the environment.


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