What is sodium lactate and why is it in my soap?

What is sodium lactate and why is it in my soap?

Date: March 20th, 2023


What is sodium lactate?

Sodium lactate is a versatile organic compound often used in food and pharmaceuticals as a preservative and buffering agent. It is a clear, liquid salt derived from combining lactic acid and sodium hydroxide. It is naturally produced in our skin and commercial production of sodium lactate is made from lactic acid derived from cornstarch, potatoes, or molasses.

Sodium lactate can be used as a food preservative as it prolongs the shelf life of food products by inhibiting the growth of spoilage bacteria. As well, pharmaceutical industries use it as a pH balancing agent and preservative.


Why is sodium lactate in my soap?

Sodium lactate may be in a bar of soap for many reasons. This versatile additive provides skin-loving benefits as well as structural benefits for handmade soap.


1) Sodium lactate is a humectant.

Sodium lactate is a powerful humectant, which means it has the ability to attract and retain moisture from the air. When used in skincare products, sodium lactate helps to improve the skin's hydration by drawing water into the upper layers of the skin, making skin soft and supple.

Additionally, sodium lactate is naturally produced in our skin and has been shown to help strengthen our skin’s moisture barrier. This means it helps prevent the loss of moisture and it helps protect our skin from external irritants and bacterial infections. It is a perfect ingredient to add to a soap tailored to dry, sensitive, or aging skin.


2) Sodium lactate is a buffering agent.

Sodium lactate is often used as a buffering agent in skincare formulations. Our skin usually has a pH of less than 5, due to the acidity of our skin’s natural oils. Buffering agents help solutions maintain a constant pH, which is beneficial to skincare as our skin is sensitive to pH changes.

When using skincare, the products we use should be as close to our skin’s pH as possible to help reduce irritation. Soaps have a low pH as well, however some commercial additives in soaps can make them more harsh on sensitive skin. Most commercial soaps are made with very acidic chemicals that are too far from our skin’s comfortable pH range.

Sodium lactate in handmade soaps helps ensure the pH of the soap remains consistent throughout the soap’s life and keeps it within the range that is safe and nourishing to our skin.


3) Sodium lactate is an exfoliant.

Sodium lactate has mild exfoliating properties. Exfoliation is important in skincare as it helps to remove dead skin cells, revealing a smoother and brighter complexion. Skin cell turnover is essential in improving skin texture and mild exfoliation can help your skin appear fuller, brighter, and more elastic.

The strength of the exfoliation in sodium lactate is perfect for handmade soap as it is non-irritating for all skin types. Chemical exfoliation with something mild like sodium lactate is better suited for sensitive skin as it’s not as rough on tender skin as physical exfoliants like poppy seeds or coffee powder.


4) Sodium lactate makes harder soap bars.

Handmade soap is made by combining oils, which are acids, with sodium hydroxide, which is a base. This process results in soap, or the sodium salt versions of the oils used. Sodium lactate is made by combining lactic acid with sodium hydroxide to create a sodium salt of lactic acid.

By adding sodium lactate salt to the soap batch, it helps harden the soap bar. This is exceptionally useful for soap formulations that contain liquid oils like olive oil, castor oil, and sweet almond oil. All these oils are liquid at room temperature and without the addition of sodium lactate, the final soap bars are quite soft and slimy. Sodium lactate allows for all of the luxurious liquid oils to be added to a soap formulation without compromising the bar hardness.


5) Sodium lactate extends the life of your soap.

Sodium lactate can act as a natural soap preservative in many ways. In the structural sense, having a harder soap bar in your bath or shower will last much longer than a soap bar that is softer. Sodium lactate’s ability to strengthen the bar allows for less of the bar to wash away when stored in a wet place like the ledge in your shower.

Sodium lactate is also quite useful in preserving handmade soap bars because their formulations often call for something called “superfat”. Superfat is the addition of extra oils in the recipe that stick around after the saponification reaction is complete. When all of the sodium hydroxide has consumed all of the oils and formed sodium salts, the extra pure oil left behind in nourishing soaps is the superfat.

Soap bars with superfat are more hydrating, moisturizing, and are best suited for sensitive skin. The sodium salts made in soap making are shelf stable which is why you can buy a bar of soap and use it a few years later and it is perfectly fine.

The downside is the superfatted oils left behind in handmade soaps are less stable. Sodium lactate acts as a natural preservative of that superfat so your soap bars are good to use for years to come. It has antimicrobial properties that can prolong the shelf life of food products, like oils, by reducing the risk of the superfat spoiling.


Overall, sodium lactate is an excellent additive for handmade skincare products.

Acting as a hardening agent, a natural preservative, an exfoliant, and a buffering agent, sodium lactate is incredibly versatile in the field of cosmetics. Softie Beauty uses sodium lactate in all of our soap formulations to give your skin all the listed benefits because we believe in simple, healthy skincare for all.


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