A breakdown of parabens used in hair products and the controversy surrounding them.

Recently, we discussed the different types preservatives found in hair care products — why they are needed, and some of the pros and cons of these chemicals. While this article addressed the different types of preservatives in a fairly general fashion, the specific subject of parabens merits further discussion because they are getting a lot of attention right now — both positive and negative. Parabens are one of the most frequently used preservatives in personal-care products, and as a result we receive many questions about them.

What are Parabens?

Parabens are synthetic esters of para-hydroxybenzoic acid (PHBA), and are often similar or even identical to certain anti-microbial agents found in various plants and berry shrubs (see Figure). These water-soluble chemicals act as broad-spectrum anti-microbials and anti-fungals in the water-continuous phase of a formulation. According to the U.S. FDA, parabens are the most utilized preservative packaged in cosmetic products. They are typically used as mixtures containing several or all of the following parabens: methyl-, ethyl-, propyl-, and/or butylparaben. The function of these mixtures is to enhance the efficacy of the preservative package, while allowing the cosmetics chemist to use as little as possible of the chemicals in her formula.

Typically, a product contains as little as 0.15 – 0.3 percent paraben by weight.

What's the Controversy?

For many years, parabens have been widely used due to their effectiveness as broad-spectrum preservatives, their low cost, their ready availability, and their perceived safety. Not only are they approved for use in cosmetics and personal-care products, but also for use in some pharmaceuticals and food products intended for human consumption. Parabens are one of the least allergenic and sensitizing preservatives currently in use.

However, recently published research results have become the source of concern for some consumers and consumer advocacy groups (such as the Organic Consumers Association). A group of researchers in England found significant levels of synthetic parabens in malignant breast tumors. Their belief is that the chemicals migrated into the area from the underarm, where antiperspirant containing parabens had been applied.

This research did not prove any sort of causality in the case of these malignancies or even a definitive correlation (non-cancerous tissue was not evaluated), but did generate sufficient concern that further research needs to be conducted. Other researchers have found that parabens can act as estrogen mimics and endocrine disruptors, but others maintain that they are so weak and used in such small concentrations that it should be of no concern.=

If one is interested in studying this topic in detail, Cornell University has an excellent resource available on their website, containing an extensive bibliography of the published research in this area.

Effects of Parabens on the Hair

Parabens are water-soluble molecules, so they are easily rinsed and do not cause any buildup on hair, even if using a shampoo-free or low-shampoo routine. They are also of sufficiently high molecular weight to prevent evaporation and subsequent water loss from the hair, which can lead to frizziness and dry hair (as in the case of low molecular weight alcohols). They are used in miniscule amounts in the formulation, and they keep the product safe and free of yucky growths.

When it comes to hair, parabens are really a relatively “transparent” ingredient when it comes to the appearance and health of one’s tresses. Regardless of this, many consumers are choosing to be cautious about products containing these ingredients because to the possible health concerns associated with them. These customers are seeking products with alternative preservative packages. As a very consumer-driven industry, we are seeing many companies respond to this demand by developing and offering paraben-free products, at all price points. Thus, consumers have many choices available to them, which make shopping and trying new things a fun, ongoing experiment!