Preservatives are, without question, an important part of any cosmetic you buy. This is especially true for products that contain plant extracts—just think about how long a head of lettuce lasts in your refrigerator before it becomes a moldy, bacteria-laden mess.

Whether it is a cleanser, lotion, toner, blush, foundation, or mascara, without preservatives these everyday items would become overloaded with microbes you don’t want on your skin or near your eyes. But what makes a good preservative or a bad one? In the cosmetic industry with insanity prevailing these days, it’s getting harder to tell as most websites want to scare you to death about the ingredients in beauty products.

In reality, the amount of an ingredient is everything. What is dangerous at a 100% concentration or when it is fed to rats or injected under their skin doesn’t often, if ever, apply to a 0.1% concentration in a skin-care or makeup product. It is also important to understand that one person’s allergic reaction doesn’t speak to the millions of other people using it safely (just because you are allergic to cats doesn’t mean everyone is).

Let’s look at the ingredient/dose issue. Take salt for example. Salt is NaCl, sodium (Na) chloride (Cl). Sodium and chloride by themselves are corrosive, but together they become a tasty seasoning for chicken. But consuming too much salt can be a serious problem for high blood pressure, but not necessarily for those who don’t have high blood pressure. It works this way for each and every cosmetic ingredient as well.

One other point: Because preservatives, natural or otherwise, exert their action by killing microbes they can also have an irritancy reaction on skin. However, because preservatives are often used in such small amounts they generally pose minimal to no risk for most people in that regard.

Trying to hone down this complicated issue isn’t easy, but here is a brief summary for some of the more typical preservatives you may find on an ingredient label:

Parabens. While natural cosmetic companies love vilifying parabens, it turns out parabens in the form of butylparaben, propylparaben, methylparaben, and ethylparaben are some of the more effective and gentle preservatives used in cosmetics. They were originally derived from plants and are mostly manufactured synthetically.
Concern over parabens made headlines because of research showing that they are endocrine disrupters. This research involved both oral administration and injection into rat skin which did show evidence of a weak estrogen effect on cells in a way that could be problematic for binding to receptor sites associated with proliferation of MCF-7 breast cancer cells. That is scary sounding stuff.
Current research investigating how parabens act when administered orally, topically, and subcutaneously to rats has shown that parabens are metabolized rapidly in living organisms and therefore cannot exhibit any adverse effects. Parabens are fully metabolized before they enter the blood stream. (For more information on parabens, visit www.cosmeticscop.com and use our Ingredient Dictionary.)

Formaldehyde. Is a very effective anti-microbial agent and can be used in a very low concentration in cosmetics. However, even in small amounts it can be irritating and when combined with amines (such as triethanolamine), can create nitrosamines. Formaldehyde in its pure form is a suspected human carcinogen.

2-bromo-2-nitropane 1-3 diol. Is a formaldehyde-releasing preservative but is not associated with the same problems as pure formaldehyde.

DMDM Hydantoin. Is a formaldehyde-releasing preservative but is not associated with the same problems as pure formaldehyde.

Imidazolidinyl Urea. Is a formaldehyde-releasing preservative but is not associated with the same problems as pure formaldehyde.

Phenxoyethanol. Is a preservative that breaks down into phenol, which is one of the reasons it is such a good antimicrobial agent. When ingested it can be problematic and exposure to the environment such as its effect on fish shows some concern, but when applied topically research shows it does not affect skin in any negative way for wound healing or other toxic reactions.

Benzalkonium Chloride. Is a relatively safe and effective anti-microbial agent.

Sodium Benzoate. Is considered to be a mild preservative with no known problems when applied topically. It is also used as a food-grade preservative.

Benzoic Acid. Is an effective preservative found in nature that contains a form of parabens. For cosmetics it is almost always synthetically derived.

Methylisothiazolinone and Methylchloroisothiazolinone. Are known to be sensitizing and are not recommended in leave-on products. They are not known to have any other problems associated with their use in cosmetics. A toxicology and medical literature search shows no other issues with these two ingredients.

EDTA (ethylenediamine tetraacetic acid). Is a chelating agent used in cosmetics to prevent metals such as copper or salts in water used in the formula from causing changes to the texture and efficacy of the product. It is not known to have any problems other than skin sensitivity. It must be used with other preservatives to be effective. Phytic acid is a possible natural alternative to EDTA.

Plant-based Preservatives. While certain ingredients have potential for preserving cosmetics, there is very little research showing they can carry the burden or remain stable to keep a product free of microbes over the life of the product. Further, because plant-based preservatives require larger amounts to preserve a product they also can become irritating or cytotoxic to skin. Plus, many of these extracts have limitations and are not without their own “scare” factor. Much research is being done on this issue.

Clove extract (eugenol). Can cause respiratory problems when inhaled.
Eucalyptus extract. One of the components of this plant is cresol, a possible carcinogen.
Cypress extract. Is a natural emission of methanol, which can cause irritation.
Sorbic acid. Can be found in nature, but is more often synthetically derived.
Tree lichen extracts. Are effective against mold and fungus, but not bacteria.
Lonciera Japanese. Is better known as honeysuckle and is a natural source of parabens and therefore can be an effective preservative.

When all is said and done, there is truly no reason to be scared of the preservatives in your product. The alternative is not a pretty picture, and natural ingredients are not without their risks. Beautiful products stay beautiful and effective when a safe level of preservatives is used in the formula.