Why Are Preservatives Necessary for Use in Cosmetic Products?

Preservatives are commonly used in cosmetic formulations, but many people question how safe they are and if they are truly necessary to include in products.

At pH Factor, we believe preservatives are 100% necessary in cosmetic products as they protect the consumer, the integrity of your formulation, the health of your skin, and your products’ longevity. They are safe and effective when used correctly. 

Here in Australia, we are serious about maintaining our high product safety and quality standards. That wouldn’t be possible without the use of preservatives and our in-house standard preservative safety efficiency testing.

Read on to find out what preservatives are and what you should consider when formulating with them.

What are Preservatives?

Preservatives play an underrated role in the performance of skincare products. They are responsible for preventing microbial growth (bacteria, mold, and yeast) in almost every cosmetic product. 

Without preservatives, most products (water-based at least) would be contaminated within days, causing serious health effects. It doesn’t matter how sterile your manufacturing space is or how much care you take when formulating your products, as soon as water is introduced into a formulation, microbial growth is inevitable if not preserved sufficiently. 

When formulating a product, you should select the correct level of preservative so that it is toxic to the harmful microorganisms and safe for personal use. To keep your products safe during their full shelf life you should preserve your products and perform efficacy testing. As a minimum, an effective level of preservative will be able to restrict growth from incidental introduction of microbial contamination during use.

Preservatives don’t have to be scary. In our view, cosmetic products are preserved to keep us safe so it’s best practice to use them. For anyone creating a natural-based skincare range, the use of preservatives becomes even more important (as there are typically more bioavailable nutrients for bacteria to feed on). 

Do All Cosmetic Products Need Preservatives? 

It’s important to note that while there are a range of products that need preservatives, not all do. Put simply, any formula that is water-based needs a preservative. Also, any product likely to become easily contaminated or come into contact with water during its use will also need a preservative. An example of this is a “Cleansing Face Oil Balm” that sits in the shower! 

Products that don’t require a preservative include mainly anhydrous formulations (containing no water) such as face oils, oil-based serums, body butters, and balms. 

Types of Preservatives 

Now that we have touched on their importance, there are several types of preservatives you can formulate with; some are “Natural Derived”, some “Nature Identical”, some “Synthetic” preservatives and some “Natural” preservatives. While there is a lot of debate around which preservatives are better, they all bring their own strengths and drawbacks and must be evaluated for their intended use in the final product.

As a beauty brand owner, there is no right or wrong way when it comes to deciding if you should preserve your products naturally or synthetically. All that really matters is that your product is preserved effectively and that you have a safe product on the market for use! 

Natural Chemical Preservatives: 

Plant extracts and essential oils are sometimes used in cosmetic formulations for their antimicrobial, antioxidant, and anti-inflammatory properties. Some examples of natural preservatives are Vitamin E, Grapefruit Seed, and Glycerine. Natural preservatives are not actually ‘preservatives.’ They can help to “boost” preservatives, but they cannot replace a preservative that actually kills microbes and inhibits the growth of them. 

Main Strengths:

  • Act as multi-functional preservation ingredient 
  • Often function over a broad pH range
  • Allow “natural” and sometimes “organic” product labeling


Main Drawbacks:

  • Loss of efficiency in dilutions
  • Fewer options available
  • Often do not inhibit microbial growth as well as synthetics
  • May have a higher likelihood of skin sensitivity
  • Consistency & potency may vary
  • Often have undesirable impacts – such as a strong fragrance (essential oils), colour, or lather


Synthetic Chemical Preservatives 

Synthetic preservatives are commonly labeled as being “unsafe” for consumer use, however, they are formulated to ensure consumer safety. They are effective at very low concentrations, which means they are generally less allergenic for sensitive skin types than natural preservatives.

Main Strengths:

  • High efficiency against bacteria and fungi
  • Many options are available
  • Well understood safety & toxicity profiles
  • Do not interfere with aspects of a formulation (colour, fragrance, etc.)

Main Drawbacks:

  • Interfere with “natural” & “organic” product labeling
  • May require a narrow pH range to be effective
  • Some consumers find them irritating


5 Main Characteristics of an Effective Preservative: 

As a formulator, when choosing an ideal preservative you should strive to ensure it contains (but not limited to) the following 5 properties: 

  1. High Antimicrobial Broad-Spectrum Efficacy: The preservative selected should kill both gram-positive (thicker cell wall) and gram-negative bacteria (thinner cell wall), molds, and yeasts. 
  2. Efficacy at Low Concentrations: Preservatives should be used at as low % as possible to avoid potential irritation. However, this % should be at a level that does not affect the function, aesthetics, or safety of the product. (Synthetic products use very low concentrations – around 0.3% of a formula – which is why they are generally accepted by all skin types). As a minimum, an effective level of preservative will be able to restrict growth from incidental introduction of microbial contamination during use.
  3. Solubility in Water: They must have adequate water-solubility (able to be dissolved) during the water phase of the product. For example, facial cleansers must have solubility to function properly. 
  4. Compatible With All Ingredients: This is so that your formulation doesn’t lose any of its preservative properties.
  5. Stable: The preservative should be formulated to adapt to temperature and pH level changes during manufacturing, storage, and usage. 


Preservative Formulating Techniques 

When formulating with preservatives, there are a range of preservative formulating techniques that are recommended to create quality preserved products. Here are two important techniques that directly impact the level of preservation: 

Preservative Efficiency Testing: This type of test provides a solid indication of the preservative effectiveness for each product under normal conditions. At pH factor, we perform this test as part of our standard procedures for each of our clients products. 

Carefully Select Your pH Level: Different pH levels can have an effect on the preservative efficiency of different products. For example, if using Benzoic Acid the lower the pH the more effective the preservative action. If you need any assistance with this, our team can point you in the right direction on the right pH level for your products. 

As a beauty brand owner or start-up, it is very important to ensure all of your products are preserved (by either natural or synthetic means) and preserved using the correct formulating techniques. 

If you are still unsure on what type of preservative system to use or how to formulate with preservatives, our experienced team of chemists can direct you based on your product desires. We hope this information about preservatives helps keep your customers safe and your products fresh. Get in touch to book your consultation.