Body Wash and Bar Soap Allergens

Bar Soap vs. Body Wash: The Danger of Allergens in Body Wash

Research Spotlight: Comparison of Contact Allergens in Bar Soaps and Liquid Body Washes.

Why Does This Matter?

Walking into any drugstore, one can see the endless arrays of body washes and soaps, all having indistinguishable claims of being fragrant and cleansing. Despite these near-identical statements, body washes and bar soaps are not all created equal; in certain soaps and body washes, allergy-causing ingredients, termed contact allergens, can cause allergic reactions when contacting the skin, otherwise known as allergic contact dermatitis. These reactions often present as itchiness (pruritus), redness (erythema), and tiny fluid-filled blisters (vesiculation).

With numerous products on the market, it may be difficult to know which products contain allergy inducing ingredients and which don’t. In addition, there has been a recent trend toward liquid body washes, especially those between 25 to 34-years-old. Therefore, a team of researchers analyzed the top cleansing products to determine their allergy-causing effects.

Bar Soap and Body Wash Allergy-Causing Ingredients: A Closer Look

In this study, researchers examined the top 50 bar soaps and top 50 body washes on Amazon.com. Each of these products had at least a 4-star average rating on the website. The researchers analyzed each of the product’s ingredients, comparing the ingredients to a list of potential contact allergens from the American Contact Dermatitis Society (ACDS) core allergen series.^[1] From this analysis, liquid body washes contained far more potential allergy-causing preservatives and surfactants than bar soaps, despite the fact that fragrances between these products were nearly identical. Furthermore, two surfactants, cocamidopropyl betaine and alkyl glucosides, were present in nearly all body washes, while being rarely present in sampled bar soaps (Table 1).

Final Points

This study found that liquid body washes contain far more preservative and surfactant potential allergens than bar soaps, and it may be beneficial for consumers with sensitive skin to use bar soaps instead of liquid body washes to prevent allergic contact dermatitis. Of note, while these potential allergens were identified by the ACDS, not everyone will react to a specific allergen. In addition, while many believe that bar soaps are less hygienic than liquid body wash, this is untrue. A study showed that after hand-washing, consumers who used liquid soaps and bar soaps had an undetectable difference in levels of bacteria.^[2] Therefore bar soaps are a safe and effective way to clean the body, especially for those with a history of allergic contact dermatitis and/or sensitive skin.