Which soap is better: liquid or lumpy, what scientists and I have learned

I never bothered with the question of choosing a soap, out of habit I found my favorite bottle with a dispenser on the counter. But the last trip to the store changed a lot, because I went shopping with a friend. Paying attention to the bottles sent to the basket, she asked only one question: "What, are you also afraid of bacteria sticking to the lump?" At first I was taken aback. And then…

Amateur arguments for and against liquid soap

To be honest: I have never thought about bacteria sticking to bar soap. I bought liquid only because it was more convenient. In response to this argument, I received an ironic chuckle from the opera "How much are you willing to pay for convenience?" There is nothing to cover with it: a bottle with a dispenser is clearly not attached to the product for free.

But honor needs to be defended, so I poked my finger in the direction of liquid soap in bags, they say, you can buy it anyway, pouring the contents into a bottle. And then another interesting statement was made: after all, we use lumpy soap about seven times less than liquid soap.

As befits in such a situation, I answered: “Who said?”, After which I received an invitation for a cup of tea and an offer to continue the discussion at home, at the monitor.

Scientists' opinions

So, returning to the issue of increased consumption. It turns out that even on this point, a full-fledged study was carried out. It was studied either by students, or by employees of the Swiss Higher Technical School in Zurich - Annette Köhler and Caroline Wildboltz. It was they who found out that when washing hands, a person on average spends about 35 g of solid soap and 2.3 g of liquid soap.

In practice, somewhere like that it turns out: 0.4-0.7 ml for one "puff" of the dispenser, which, as usual, is pressed 2-3 times, because one portion is not enough. Therefore, this round of handy bottles also lost. But the excitement has not gone anywhere, and therefore we "go" further - what is there with the bacteria on the bars?

This answer came to us from America, where the myth of bacteria breeding on the surface of bar soap is very popular (according to According to the report of the Mintel research group, in 2016 60% of respondents aged 18 to 24 and 31% over the age of 65 were convinced of this. years old).

So, it was not possible to find out whether bacteria multiply on the bar. And here the possibility of disease transmission through hand washing with the same bar of soap has been tested many times. Most of all I was interested in the results of the studies that were published in the New York Times magazine.

The first of these was held in 1965. The hands of one of the participants were contaminated with bacteria, and after he washed them with soap, the used bar was passed on to another subject, who also washed his hands. Result: The used bacterial strains were not found on the hands of the participants in the experiment.

Second study was held in 1988. This time, the bacteria were settled on the bar itself, which was then used by the participants in the experiment. The result is the same: diseases are not transmitted in this way.

What do the doctors say?

Old research is good. But what about the new ones? To be sure, I immediately went to the official website of the WHO (it is not for nothing that this organization recommends washing your hands with soap and water in any incomprehensible situation - they probably know something). So, I didn't find anything about choosing a soap. Nothing at all. Searches for information on the Centers for Disease Control and Prevention website yielded a similar result.

And what do our doctors say about "which is better"? The same play - on the soap itself, viruses and bacteria can linger (and under certain conditions, they can be in liquid manage to penetrate), but in the process of using this agent, pathogens "miraculously" disappear.

This "miracle" happens because soap does not destroy viruses and bacteria, but washes them away. At the first soaping, it binds the dirt particles on the surface of the skin. By thoroughly rubbing damp skin with foam, we help the active ingredients to cope with this task.

But the second soaping allows you to get rid of pathogens in the pores - those after 10-15 seconds intensive processing and contact with water expand, so that the foam penetrates inside and flushes out the remaining "Living creatures".

However, washing hands too thoroughly also leads to negative effects. The fact is that when used frequently, the soap can break down the lipid barrier that maintains the integrity of the skin. The result of such an impact is defenseless intercellular spaces, into which pathogens can "seep". With an eye to this, another question arose.

Are there any line-up differences?

Water, fragrances, dyes, skin softeners - all this is in liquid and bar soaps. True, the first one usually contains a larger number of items, a couple of which can be assigned to synthetic surfactants. And in the bars, such surfactants can also be found if the manufacturer seeks to please consumers with abundant foam.

The only significant difference that pops up when looking closely at the composition is sodium stearate in bar soap and potassium stearate in liquid. But these components also have approximately the same effect on the skin. Does this mean that it is almost useless to look for arguments "for" and "against" in the composition?

The answer was given by my opponent: The pH of liquid soap is close to neutral (5.5), but a bar cannot boast of such a property (its pH is usually closer to 7). This difference becomes possible due to the amount of synthetic surfactants and other additives, of which there are always more in a liquid solution.

This means that solid soap does not allow bacteria to relax - they cannot feel normal in an alkaline environment. True, for the same reason, the bar also causes more serious damage to the lipid layer of the skin, which in turn entails a weakening of the natural defense and dryness.

But this also explains the presence of preservatives in liquid soap - they are needed in order to prevent the multiplication of microorganisms in the coveted bottle. And these preservatives can irritate sensitive skin and cause allergies. In addition, these substances, like synthetic surfactants, cause more harm to the environment than caustic saponified vegetable and animal high-molecular fats, which form the basis of lump soap.

Bottom line: again, almost a draw. Turns out that the choice between liquid and lumpy soap is a purely individual matter. The first option is more suitable for those who are ready to pay for convenience, but at the same time are not very worried about the environment. The second one helps to save money, does less harm to the environment, but cannot boast of a gentle effect on the skin.

On this cheerful note, my friend and I parted ways, each remaining at its own discretion. But I'm curious to know what you think about this. Which soap is better: liquid or lumpy?