Why the Ingredients Matter Part 4: Preservatives

It might surprise you that makeup & shampoo & things have an expiration at all. But cosmetics are just as likely to attract and grow bacteria and other microorganisms as any other product that has a high enough water content. Microorganisms require only 3 things to grow: water, air and a food source. Most cosmetic products have plenty of water and other nutrients, as well as a hospitable pH and temperature. The humidity in your bathroom doesn’t help matters. From the moment you open your cosmetics and expose them to the open air, they become the perfect place for molds, yeasts, and bacteria to set up shop and start multiplying.    

So that’s obviously gross. Nobody likes the idea of having a refreshing shower, only to grab their shampoo and realize it’s gone all moldy. The best way to prevent that is with the use of preservatives. 

Preservatives act as antimicrobials to prevent the growth of microorganisms in our products. They are essential for stability, odor, appearance and texture, to extend the shelf life of our products. Most importantly, they are important for consumer safety. Without them, cosmetic products can become contaminated, leading to faster product spoilage and possibly irritation or infections. 

As it usually happens in life, natural synthetics tend to be much more expensive to produce than synthetic preservatives. And to no one’s surprise, most companies tend to take the cheaper route. There are many synthetic preservatives, and most of them have really long, science-y names, like Methylchloroisothiazolinone. But there’s one group of synthetic preservatives I’d like to focus on, Parabens. 

A paraben by any other name is still a paraben, and some of those names include methylparaben, propylparaben, butylparaben, and ethylparaben. Cosmetics typically contain mixtures of different types of parabens. The danger of parabens is that they can mimic the hormone estrogen in the body and disrupt the normal function of hormone systems, aka an endocrine disruptor.  Studies have found parabens have been linked to fertility issues in both men and women, as well as premature birth and low birth weight in infants. And they’re pervasive; a CDC study detected trace amounts of propylparaben in 92% of people tested, and butylparaben in 50% of those tested. Parabens have even been found in ocean waters and  fish, which is especially problematic, as even trace amounts of butylparaben can kill coral.


The most concerning thing about parabens is cumulative exposure. Parabens are most generally found in products at a rate of roughly 0.3%, but are “reasonably considered safe” at up to 25% of a formula. Although 0.3% isn’t a lot, parabens can be found in shampoo & conditioner, moisturizers, facial cleansers, sunscreen, deodorant, shaving gel, toothpaste and makeup. Many of us use several, if not all, of these in the run of the day, so your exposure adds up quicker than you might think.    

By now, you’re probably ready to swear off any product with preservative in it. And that’s something you can choose for yourself! There are a small number of products on the market that have been made without preservatives. The downside is they have a very short shelf life, and usually need to be kept refrigerated. One solution might be to produce your own products without preservatives in small batches at a time. A simpler solution is to use natural preservatives. 

Natural preservatives are not the most popular choice in cosmetics for a couple of reasons. First and foremost, it’s expensive to harvest the natural products, and generally it takes a lot more raw material to produce the same amount of natural preservative than it does synthetics. And natural preservatives don’t work as well on their own as their human-made cousins. Several preservatives must be combined to get the full scope of protection from microorganisms. 

One of the most common natural preservatives you might not think of is vinegar. Think about how well it preserves pickles! In cosmetics, it would appear as acetic acid. There are a few other acids that work well as preservatives, like sorbic acid, and citric acid. Oils and oil extracts are common too, including neem oil extract, rosemary oil extract, grapefruit seed oil, and lavender and tea tree essential oils. Vitamin E oil contains antioxidants which help extend the life of products. Because natural preservatives must be used in larger amounts and in combination with each other, they sometimes change the color, smell, or consistency of the product. This is why Upfront Cosmetics uses lavender and tea tree oils in our preservative blend for several of our shampoo bars, because in addition to their germ-fighting properties, they give the bars a refreshing smell! 

Preservatives in cosmetics are pretty well unavoidable, but we can make the choice to use products with natural preservatives rather than synthetic. It’s also important to remember to keep an eye on the expiration date of your products, and throw them out if they’re past date. Always store cosmetic products in cool, shady locations to keep formulas from spoiling. Use clean fingers and make sure to completely close containers after use to prevent microbial contamination. And if you aren’t sure about the freshness of a product, it’s better to be safe than sorry; toss that thing. When in doubt, throw it out!