Sodium hydroxide (NaOH) is a white and odorless alkaline solid. Commonly known as caustic soda. It is a very corrosive and reactive mineral compound. thisThe subject makes many people ask if it is safe to use sodium hydroxide in soap and cosmetics. The short answer is yes, because although sodium hydroxide is used in soap making, it no longer has caustic properties in the form of a saponification reaction, and it is also used in many chemical processes to produce various products, including cosmetics. Sodium hydroxide is used in low concentrations as a pH stabilizer or pH regulator. Sodium hydroxide is also used in many other common household products, including drain cleaners, pharmaceuticals, and in some food products.

Applications of sodium hydroxide

There are many uses of sodium hydroxide. Sodium hydroxide is a versatile compound that is used to produce all kinds of products, even paper and petroleum products. It is also found in many household products, some of which include:

• Cleaners : NaOH is commonly found in sewage cleaners. Sodium hydroxide works to break down grease and oil, which are the main cause of clogged drains. Also, when mixed with chlorine, it is used to produce bleach.
• Soap: If sodium hydroxide is listed in the ingredients list of your liquid or bar soap, sodium hydroxide is an essential ingredient during soap production and is completely harmless once the soap is made; Because its nature has changed during the saponification process.

• Food: sodium hydroxide is used in very low concentrations in food production. Some examples include peeling fruits and vegetables for canning, sweetening olives, and adding a golden brown color to pretzels.
• Medication: Sodium hydroxide is found in many headache medications, anticoagulants (prevents blood clotting), and cholesterol-lowering medications.
• Water treatment: Local municipalities use sodium hydroxide to stabilize water acidity and remove metal impurities from water. It is also used to make a water disinfectant (sodium hypochlorite).

Use of sodium hydroxide in skin care health products

The pH of human skin is towards acidic pH and usually varies between 4 and 7. Maintaining this acidity (known as the “acid mantle”) provides a layer of protection (normal flora) against environmental factors such as allergens, pollutants, and bacteria. If the pH of skin care products deviates from the skin’s natural pH, the skin’s acidic defenses are compromised, which may also increase the risk of premature aging. It is much safer to use skin care products with low concentrations of sodium hydroxide.

Therefore, the use of sodium hydroxide in cosmetics and health products is usually only suitable for adjusting the pH in the optimal range for the skin, not to produce products with a pH higher than the pH of the skin.

Application of sodium hydroxide in soap production

Technically speaking, soap is a salt product made by combining an alkali with fat or fatty acids. Alkaline composition is the same game composition that is responsible for creating a slippery state after soap production. Fats (or fatty acids) are the same as oils.

Sodium hydroxide is a substance used in a chemical reaction to produce other substances. Caustic soda is an essential ingredient in soap making and it causes the saponification process to take place. When sodium hydroxide flakes or grains are added to a liquid, a sodium hydroxide solution is formed; Sodium hydroxide solution contains separated sodium and hydroxide ions. This solution, when mixed with oil or fat, leads to a chemical reaction called “saponification”.

Today, most industrial soap making is done through a continuous process that produces a steady stream of soap instead of small batches. Manufacturers first split the natural fats into fatty acids and glycerin, usually through a long, vertical steel column called a hydrolyzer, which uses high temperatures to break the fat into its two components. After separation, the fatty acids are distilled for further purification. Then, the purified fatty acids are mixed with a precisely measured amount of caustic soda. As the process continues, soap is created. During this stage, other chemicals may be added to increase shelf life, cleaning power, or marketability, such as natural essential oils such as lavender essential oil, rose essence, etc., which in addition to marketability, can also have therapeutic or beauty properties. But you can also prepare liquid soap with caustic soda in small batches.

At its most basic level, soap making requires sodium hydroxide, water, and oil/fat to begin the chemical process of soap making. Water and fat do not mix well by themselves. Here the role of sodium hydroxide appears. When sodium hydroxide is added to water ( not the other way around! ), it creates an exothermic reaction , meaning it heats up very quickly. Then soap makers combine this aqueous solution of sodium hydroxide with an oil or fat base to produce soap.

Sodium hydroxide is mixed with oil and soap is produced. First, you have sodium hydroxide, water, and oil. Then the curing process begins and after a few days, sodium hydroxide, water and oil turn into soap. At the end of the cooking process, perhaps 3-4 weeks (sometimes longer), there is no sodium hydroxide left in the soap, no oil, no water, but what remains is pure soap. So in short, sodium hydroxide can turn oils into soap. And that means it helps oils and fats to lather and become soapy.

Safety issues of sodium hydroxide

The safety of sodium hydroxide strongly depends on the concentration level, with higher concentrations creating more safety problems. Other factors that affect safety include duration of exposure, area of ​​exposure, and environmental conditions. Sodium hydroxide is very caustic and corrosive and may cause skin and eye irritation or respiratory problems if inhaled. Never put pure sodium hydroxide on the skin. Sodium hydroxide can cause skin symptoms such as mild to severe chemical burns or holes in the skin and underlying tissues.

Sodium hydroxide is present in many cosmetics at low concentrations (often 5% or less). According to a review by the US Environmental Working Group (EWG), the presence of sodium hydroxide in personal care products has not been linked to cancer, developmental and reproductive toxicity, nor allergy or immunotoxicity. The US Food and Drug Administration (FDA) has approved sodium hydroxide as safe for use as a food additive at levels below 1%.