Bar Soap vs Liquid Soap

Clean the World Asia Soap Recycling

I remember as a child, my whole family used the same bar of soap. Gradually though the bar of soap seemed to disappear and was replaced by liquid hand and body wash. Using bar soap had come to be considered unhygienic and a source of bacteria. The strange thing is even though we shared soap, we seldom got sick and had no diseases. In the last decade, I’ve switched back to bar soap again and am still reasonably healthy. So I am just incredibly lucky or have makers of personal care products been masterfully manipulating of our fear of germs?


The switch from bar soap to liquid has been driven by a fear of bacteria lurking on bar soap. Companies encouraged the notion that using liquid soap was more hygienic.


This NY Times article which asked “does each member of the family need an individual bar of soap to prevent spreading germs, or do we have to switch to liquid soap?” came to a very different conclusion. It cites studies that concluded washing even with contaminated bar soap is unlikely to transfer bacteria, especially if the bar gets rinsed off between uses. 


According to the NY Times:

“… soap bars were inoculated with E. coli and P. aeruginosa bacteria at levels 70 times as high as those reported on used soap bars. Then, 16 people were told to wash their hands as usual with the inoculated bars.


“After washing, none of the 16 panelists had detectable levels of either test bacterium on their hands,” the researchers wrote. “These findings, along with other published reports, show that little hazard exists in routine handwashing with previously used soap bars and support the frequent use of soap and water for handwashing.”

研究報告寫道:“洗滌後,16名小組成員中沒有一人手上有任何可檢測水平的試驗細菌。” “這些研究結果以及其他已發表的報告顯示,在使用已經使用過的條狀香皂進行常規洗手時幾乎沒有危險,並支持經常使用條狀香皂和水進行洗手。”

So how can a bar of soap have bacteria on it and yet not spread germs? Simply, washing is a two step process. When you lather up the oil attracting end of the soap molecule picks up grease and oils on your skin. When you rinse, the water attracting end of the molecules follow the water, letting you rinse the soap molecules — and their attached impurities — away.

那麼一塊條狀香皂怎麼會帶有細菌而又不會傳播細菌呢?簡單地說,洗滌是一個兩步過程。當你洗滌時,泡沫吸收皂分子的末端,會吸收皮膚上的油脂和油份。當你沖洗時,吸引分子末端的水跟隨水流,讓你沖洗皂分子及其附著的雜質  。

This leads us to the next question “if liquid soaps provide no hygiene benefit, why have companies been so aggressive in marketing liquid body washes?”


This article on US website DailyFinance may provide a clue. Their comparison showed bathing with the recommendedamount (2 teaspoons) of Olay body wash cost HK$1.33 per wash while bathing with Ivory bar soap cost just over HK$0.09, providing a significant profit motive  for companies to get us to switch.


Another often cited advantage of liquid body wash is that it allows manufacturers to add moisturizers. While a complaint against bar soap is that it may be harsh and drying. In fact, there are many varieties of bar soaps in the market that contain glycerine and natural oils that moisturize the skin. These soap can be just as gentle and mild on the skin, negating any advantage of body washes. If body washes have no advantages, do they have any disadvantages? It turns out there are many. 


Containing lots of water, body washes are also much heavier than bar soap, resulting in a significantly higher carbon footprint for transportation. Packaging for body washes are made of plastic that ends up in the landfill or our oceans (see picture below). Bar soap has a clear edge in transportation, packaging and disposal.


Lastly, lets take a look at what’s inside. Most liquid body washes are made of petroleum, while many traditional bar soaps are made of saponified animal fat and plant oils. Liquid soaps need the addition of emulsifying agents and stabilizers to maintain their consistency. Although these chemicals may have been approved by the relevant authorities for use on humans, the  testing procedures do not include the consequence of long term use or interactions between these and the myriad of other chemicals in our environment.


For example, diethanolamine (DEA) is commonly added to confer a creamy texture and foaming action. It inhibits in baby mice the absorption of choline (not to be confused with chlorine), which is an essential nutrient necessary for brain development and maintenance. High concentrations of DEA were also found to induce body and organ weight changes, and mild blood, liver, kidney and testicular systemic toxicity in mice. A 2009 study also found that DEA is potentially toxic for aquatic species.

例如,通常加入二乙醇胺(DEA)以賦予乳脂質地和發泡作用。它抑制了小鼠膽鹼的吸收(不要與氯混淆),這是大腦發育和維持所需要的重要營養素。結果還發現高濃度的DEA誘導小鼠體重和器官重量變化,以及對輕度血液,肝臟,腎臟和睾丸引發的毒性。 2009年的一項研究更發現,DEA對水生物種具有潛在毒性。

I can only conclude then that liquid body washes really provide little or no benefits to the consumer, create significant profits for manufacturers, and are tremendously harmful to the environment. So are you ready to switch back?


Written by Fai Hui from Go Green Hong Kong. You can read the original article HERE

由Go Green Hong Kong的 Fai Hui 撰寫。請按此閱讀原文