Center for Research on Ingredient Safety

Preservatives are not only necessary to stabilize our food supply; they play a crucial role in keeping our cosmetics safe.

Many of us don’t think about our cosmetics as products that can spoil or grow bacteria, fungi, and yeasts, but without the assistance of preservatives, our cosmetics could become harmful. Let’s take a look at the preservatives that keep the cosmetics for our skin safe. 

Are there different types of cosmetic preservation?

Much like keeping foods fresh and safe, cosmetic manufacturers also implement physical and chemical preservation techniques. This includes optimizing packaging, processes, and ingredients, so the end product meets all safety requirements. 

Why do we need preservatives in cosmetics? 

Our skin is the largest organ of our body. It acts as a protective barrier to the elements and helps control thermal regulation, infection, and much more. Our skin reacts and can adapt to the environment around us, and this includes the cosmetic products we use on our skin.

Skin also has an optimal pH level between 4-6.5. A pH level refers to the acidity or alkalinity of an environment. Knowing the pH level is essential because many microorganisms (e.g., bacteria, fungi, yeasts) cannot live in an environment with a pH level below 4 or above 10 but thrive in a pH environment similar to our skin.

While we can design products on the extreme ends of the pH scale to prevent microorganism growth, the products would likely irritate or damage our skin. Therefore, we rely on preservatives to create an inhospitable environment for microorganisms while maintaining an optimal pH level for our skin health. 

Microorganisms grow readily in water, and most cosmetic products contain water as the largest or one of the largest ingredients. Additionally, the nutrients, vitamins, and many of the active ingredients in cosmetics can make excellent microorganism food. Thus, providing a prime environment to fuel their growth. 

Another issue preservatives solve is contamination. Most people don’t think of their hands as contaminates, but our hands contain microorganisms and are not sterile. So, every time we put our fingers into a jar of lotion or push the pump on a lotion bottle we are introducing new microorganisms into our products that can quickly cause spoilage, or worse, without preservatives. 

People typically store cosmetic products in bathrooms that become humid and warm during showers and can be close in proximity to a flushing toilet that can mist particulates onto or in our products. Again, this is where preservatives prevent microorganism growth even in this ideal environment. 

Do cosmetics need to use antioxidants?

Much like food, cosmetics sometimes require antioxidants, but since we do not ingest these products like we do foods, we use antioxidants in different quantities for different purposes. For example, an antioxidant ingredient such as vitamin E may be an active ingredient or may be present to ensure the color and texture of a product.

Cosmetic manufacturers take care to ensure that products only contain what is necessary for it to function effectively.

Do cosmetics go bad even with preservatives?

Yes, cosmetics, like food, have an expiration date even if they contain preservatives. Unlike food, the expiration date for a cosmetic product is two-fold. 

Products will contain an unopened or shelf-life expiration date on the packaging. This date tells us when a product goes bad even if it remains unopened and unused.

The second expiration date is typically printed on the product itself and it states the number of months the product remains fresh and safe for use after opening. In the below image, you'll see the common symbol that contains the expiration date in months found on most cosmetic packaging. 

Are cosmetics with preservatives safe to use?

Yes, cosmetics that contain preservatives are safe to use based on current science. However, the U.S. FDA does not currently regulate cosmetics; companies and individuals who manufacture or market cosmetics bear the legal responsibility to ensure the safety of their products. 

The U.S. FDA neither approves nor provides legal requirements for all ingredients in cosmetic products, but there are required labeling laws that ensure the public knows the products' ingredients. You can look up any cosmetic ingredient for science-based safety report at https://www.cir-safety.org/ingredients.

Additionally, the FDA continues to seek understanding around the safety of many cosmetic ingredients and has created a form for people to share their experience or reaction with specific cosmetics.

What are common cosmetic preservatives?

• Aldehydes, such as formaldehyde, DMDM hydantoin, imadozolidinyl urea, diazolidinyl urea: safeguard against bacteria and some fungi
• Glycol ethers, such as phenoxyethanol and caprylyl glycol: safeguard against some bacteria
• Isothiazolinones, such as methylisothiazolinone: safeguard against bacteria and fungi
• Organic acids, such as benzoic acid, sorbic acid, levulinic acid, anisic acid: safeguard against fungi and some bacteria
• Parabens, such as methylparaben, ethylparaben, propylparaben, butylparaben, isobutylparaben: safeguard against fungi and some bacteria

Can I create cosmetics at home, should I buy indie brand cosmetics?

You can certainly create your own cosmetics; however, if you do not use preservatives in your homemade products, you should treat your cosmetics like you would fresh fruits or vegetables and understand that the shelf life of your products will be limited. The U.S. FDA provides a fact sheet to help you understand best practices for cosmetic creation. 

When buying cosmetic products from an indie brand, contact the seller and ask them how they ensure products remain fresh and safe. Reputable and responsible indie brands will be able to explain what products and processes they use to keep their cosmetics safe. 

In our next several 101 series installments, we’ll explore the safety of specific preservative ingredients, some of which have been receiving increasing attention.