You must have had the experience that when taking a bath, you originally wanted to wash your hair with some shampoo, but accidentally pressed it into shower gel. After pressing it out, I didn't want to waste it, so I directly smeared the shower gel on my head, and found that I could still wash the foaming and wash off the hair oil, although it felt different from shampoo, but I could also wash my head clean.
So what exactly is the difference between shampoo and shower gel? Can they be mixed?
If you use them only for the most basic oil removal, it can indeed be mixed. Because their basic ingredients are actually "surfactants" [1], the molecular structure looks like this, similar to a match.
Cartography: Popular Science China New Media
When washing hair or body, the "matchstick" of this "match" will insert oil inward, and multiple "matches" will gather together to form a circle of such "micelles", trapping the oil in it; At the same time, the "match head" on the periphery of the "micelle" is closer to the water molecules, and the "micelle" can easily dissolve in the water and move with the water flow, leaving the body or hair surface, thus achieving a cleansing effect.
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But the same cleaning principle, shampoo and shower gel play a cleaning effect, but not exactly the same.
In shampoos, mainly anionic surfactants are used, which can increase the negative potential of dirt particles and hair surfaces, and use the principle of homosexual repulsion to enhance the decontamination effect.
In the shower gel, in addition to anionic surfactants, amphoteric surfactants are also used, which are resistant to hard water [2], even if there are more calcium and magnesium ions in the bath water, it can also function normally. In addition, amphoteric surfactants also have strong emulsification and foaming, which can produce more foam, so that the oil and fat more fully and evenly form an emulsion, which is washed away by water, so it is more suitable for use on the surface of the body.
But for hair, it's not enough to clean oil, it's just as important to keep it smooth.
On the microscopic surface of the hair, there is a layer of hair scales[3], which are made up of many tiny scales stacked on top of each other. During the washing process, if the hair scales are damaged and upturned, the friction between the hair strands will increase, and the hair will appear dry and frizzy and tarnished.
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To avoid this, many shampoos add a substance called polydimethylsiloxane, commonly known as silicone oil. It fills damaged areas of the hair scales, forming a protective film that smoothers and smoother hair.
Photo by Xu Lai
So on the whole, shower gel and shampoo are actually not suitable for exchange. It is not a good idea to buy less bottle in order to save money or trouble~
In addition to between shampoo and shower gel, shampoo, shower gel and facial cleanser and soap are actually not suitable for mixing.
The surfactant used in some facial cleansers is amino acid surfactant, which, like your skin, is weakly acidic, is milder and less irritating than shower gels and shampoos, and protects the skin barrier while cleansing. If you just wash your face, it is still recommended to use a facial cleanser.
The problem with soap is that the ability to remove oil is too strong. Soap is alkaline after hydrolysis, and washing the body with it can easily irritate the skin, and may also break the skin's water-oil balance system, causing the skin to dry out excessively and produce a feeling of tightness. Sometimes, in order to compensate for the loss of oil caused by soap, the skin will secrete more oil, causing your body to become oilier and greasy for a period of time after you took a bath...
After all, the reason why each cleaning product is designed with a different formula is because they have their own suitable scenes, and only by performing their own duties and doing what they are good at can they make the most difference. If you have to wash your whole body with a bottle of shower gel, it is equivalent to letting a restaurant employee be a cook, waiter, manager, and dishwasher at the same time: yes, but not necessary~
Resources:
[1] MENG Weihua,LIU Xianjun. Overview of Ingredients, Formulation Process and Market Overview of Shampoo[J]. China Laundry Products Industry, 2016(4): 71-77. DOI:10.3969/j.issn.1672-2701.2016.04.008.
[2] FANG Yun, XIA Yongmei. Amphoteric surfactants (IV) General properties of amphoteric surfactants[J]. China Surfactant & Surfactant Industries,2000,30(6):47-50. DOI:10.3969/j.issn.1001-1803.2000.06.014.
[3] HU Xiuhong. Research on damage and protection of hair fiber[D]. Zhejiang:Zhejiang Sci-Tech University,2009. DOI:10.7666/d.y1606189.