Citric Acid In Hair Care: Myths Dispelled - AMR Hair & Beauty

Citric Acid In Hair Care: Myths Dispelled

Jul 22, 2021Scott Peers

Citric Acid in hair care has been talked about a lot on the internet in recent years. There is still a lot of confusion out there regarding Citric Acid and what it can and can't do. For example, will citric acids in hair care products lighten hair?

Mixed information is being shared and it's easy to understand why there's so much confusion.

We are here to dispel some of the rumours and give you a better understanding of what citric acid can be used for in hair care.

Working with citric acid for many years as a chemist, I'm able to shed some light on the pros and cons of using it and what to look out for.


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Understanding The Science Of Skin pH

To properly understand what citric acid does to hair and skin we need to understand the pH of hair and skin. 

Your skin's outermost layer is called the acid mantle and the acid mantle is made up of an oily substance called sebum which is excreted from the skin's sebaceous glands. The sebum mixes with lactic and amino acids from sweat creating the skin's pH, which should be somewhere between 4.5-5.5.

A vast majority of personal care products are formulated to sit within this pH range. Some products will sit outside of this pH range because of the nature of the products being formulated. Selecting the correct preservative for both the application and efficacy is important and many preservatives have a pH range in which they are most effective. In fact, some preservatives will not work at all if the pH is out of the suggested range.

The human scalp is still part of the skin, so the pH range is 4.5-5.5, however, the hair shaft pH is 3.67. Any product applied on hair that has a pH higher than 3.67 causes an increase in the negativity of the electric network of the hair, that is, an increase of static electricity and the repulsion between strands. The hair fibre surface bears a negative charge because of its low isoelectric point. Positively charged ions are attracted to the negatively charged surface, thus helping to overcome the electrical barrier for negatively charged ions called anions.

Balancing pH

When we rinse our hair, the water leaves both the scalp and hair shaft at a pH of about 7. This can cause issues with the scalp and can cause hair to be frizzy and easily tangled. When that happens, an increase in negativity occurs. The negative electrical net charge generated will tangle the hair and make it hard to comb, thus causing the frizz effect.

In alkaline pH, hair has an increased capacity to absorb water. Water penetrates the hair cuticle that is open, hydrating the strand and breaking the hydrogen bonds of the hair strand.

Essentially, you will need to decide what effect you want your product to have on the hair to determine its ideal pH. If you desire more volume, a higher pH might be beneficial. People with fine lifeless hair will benefit from the pH products that will give them that fullness/texture they so much desire.

If you are the type of person that desires smooth and frizz-free hair, products with a lower pH would be a better fit for your type of hair.

May I also add that every ingredient used in hair care has its unique pH, so it is important to adjust the pH of the final product to suit the hair type. Plenty of science has been trialled and tested to make sure it's safe and effective.

Where does Citric Acid come from?

For centuries scientists have been trying to emulate nature by synthesising citric acid. In 1784, citric acid from lemons was isolated for the first time. Commercialisation did not begin until the mid-1800s.

Soon, the extraction process quickly became uneconomical as the demand for citric acid grew. During the 19th century, scientists discovered a way of synthesising citric acid through microbial fermentation. The development of this entirely new production technique proved to be viable on an industrial scale. As a result, fermentation technology gradually replaced earlier extraction processes.

Where Citric Acid Is Used

Citric acid is used in numerous consumer products, from foods to pharmaceuticals and detergents. Commanding over 70% of the world market for fruit acids, citric acid offers formulators a unique combination of benefits.

Based on its unique chemistry with three carboxyl groups, citric acid is the most widely used acid in food applications.

  • In the food and beverage industry, citric acid is the preferred acidulant (chemical compound to flavour food) due to its high solubility, pleasant tart taste and excellent flavour-blending characteristics.
  • Citric acid stabilises colour, taste, flavour, and vitamins in various food products including processed fruit, potatoes, vegetables, fish, and meat products.
  • As a buffering agent, citric acid helps formulators to maintain optimum pH for maximum stability of active ingredients.
  • Citric acid shows the widest buffering capacity (pH 2.5-6.5) of all organic acids. As such, it can give the food, personal care, and pharmaceutical industries the flexibility needed to formulate optimal end products.
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As we can see, Citric Acid may have originated from lemons, but today the Citric Acid that we see in hair care products such as 18 in 1 detox shampoo comes from fermentation technology.

Hopefully, now you have a better understanding of the important role Citric Acid plays in hair care products that cater for each hair type. Without Citric Acid, we would not enjoy many of our favourite products.

The majority of multinationals use Citric Acid in their products and have done so for years.

I hope this has cleared most of the misconception that is out there, especially that if a product has Citric Acid, it alters your hair, colour, or is to be avoided with services carried out in hair salons.

There is no need to get a special treatment to remove the Citric Acid from your hair.

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