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Sodium Benzoate Preservative Formulating Guidelines & Safety

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Sodium Benzoate is a naturally derived preservative that is most effective at a very low pH.

It is excellent for use in cosmetics; it is generally regarded as safe and can be used in various products. 

It can also be used to help mask strong fragrances in skincare products and act as a corrosion inhibitor. It is relatively effective against yeast and molds and is often combined with other preservatives like potassium sorbate.

Sodium Benzoate Preservative

Sodium Benzoate Quick Facts

Sodium Benzoate INCI:
Sodium Benzoate
COSMOS and ECOCERT Standards:
Sodium Benzoate meets COSMOS and ECOCERT standards
Sodium Benzoate Ingredients:
Benzoic acid, sodium hydroxide
Sodium Benzoate Preservation Activity:
Sodium benzoate works by releasing benzoic acid, which is absorbed into cells, inhibiting the growth and replication of microorganisms. This activity increases as pH falls.
Is Sodium Benzoate Water Soluble?
Sodium Benzoate is water-soluble.
PH Compatibility:
Sodium Benzoate can have some activity at a pH of 6 but is most effective at a pH of 3.
Recommended Usage Levels:
The recommended usage level for Sodium Benzoate is up to 1%.

What is Sodium Benzoate?

Sodium Benzoate Preservative

Sodium Benzoate is an inactive salt in benzoic acid. It is soluble in water, where it converts to its active form, benzoic acid, in low pH environments. 

Sodium Benzoate is not a broad spectrum preservative for cosmetic use and should be used in combination with other preservatives. 

It is most effective at preventing fungi growth; it does offer some protection from yeast and bacteria.

It is often used in combination with Potassium Sorbate in low pH products to protect against yeast and mold.

Is Sodium Benzoate Safe?

Sodium Benzoate is generally regarded as safe to use in cosmetics.

There a few ingredients that are not recommended to use with Sodium Benzoate, such as L-Ascorbic Acid and Citric Acid.

So this would not be a good preservative choice for Vitamin C Serums or creams.

Is Sodium Benzoate Natural?

Sodium Benzoate is a man-made compound. It is derived from Benzoic Acid, which can be found in many plants.

Sodium Benzoate Uses:

Sodium Benzoate Preservative

How to Use Sodium Benzoate Preservative in Formulations

Sodium Benzoate in cosmetics is most effective at a lower pH, preferably a pH as low as 3. It does have a small amount of efficacy at a pH of 6. 

When adding Benzoic Acid to a formula, the pH should be lowered to facilitate benzoic acid release. 

This preservative is often mixed with other preservatives such as potassium sorbate to create a synergistic effect covering a wide variety of bacteria, yeast, and molds. 

It is recommended that it not exceed a 1% usage level and that it is not mixed with L-ascorbic acid or citric acid.

Be sure to test your product pH before adding preservatives to ensure that they work most effectively.

Sodium Benzoate Warnings

Sodium Benzoate is generally safe, but it needs to be mixed with other preservatives such as Potassium Sorbate to provide broad-spectrum protection. 

Many ingredients can be safely combined with Sodium Benzoate; however, there are two that are cause for concern.

L-ascorbic acid should never be mixed with Sodium Benzoate; this combination can form a benzene compound, a known human carcinogen. 

Combining these two preservatives together will often not produce benzene; other conditions must be met; however, the risk associated with potential benzene formation is not worth it. 

Another ingredient that is often used with L-ascorbic acid is citric acid. It is thought that these three ingredients combined can cause accelerated benzene formation. 

Where to Buy Sodium Benzoate Preservative

Other Natural Preservative Options

If Sodium Benzoate doesn't work for your formulation, check out these other natural preservative options.

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Sodium Benzoate Preservative
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