Unfolding the truth behind dry shampoos and their effects on health

 
BREAKING AWAY from the convention that shampoo is always in liquid form, dry shampoo is a powder type shampoo that gets rid of greasiness in hair without the use of water. Dry shampoos have officially solidified their place in the global health and beauty market as they are continuously purchased by consumers worldwide. An increase in their popularity is explained by the variety of purposes they serve—they not only work as cleansing products but also as styling items. However, despite what the name suggests, dry shampoos aren’t actually shampoos everyone is familiar with. On that account, it is important for consumers to know the right method of using dry shampoos. 
 
The history of dry shampoos
   Pierre Fabre, the owner of Klorane—a French cosmetic brand, first developed dry shampoos in 1972 when he, a pharmacist back then, encountered a number of women in maternity wards who were struggling to take showers and wash their hair. Lee Moon-young, the marketing manager of Pierre Fabre Dermo-cosmetique Korea elaborated in an interview with The Yonsei Annals that “In order to improve [the patients’] situations, Fabre decided to develop shampoos in powder form so that patients could easily use them without having to go to shower rooms.” Dry shampoos then quickly gained popularity among ordinary citizens due to the convenient application process and Europeans’ high degree of exposure to limewater. According to the marketing director at the Klorane headquarter, many Europeans are reluctant to wash their hair with domestic water because they believe that its limewater components will damage their scalps*. People in Europe have therefore started to frequently reach for dry shampoos as alternatives for washing hair with water.  
   Dry shampoos were less known in Korea until 2012 when a British brand called Batiste launched the products for the first time. Following Batiste, other hair brands such as Klorane, Aveda, and Mise-en-scène have launched their own dry shampoo products in the Korean cosmetics market**. According to MK News, sales for dry shampoos have increased significantly, rising by 54% since 2017. The main users of dry shampoos are the younger generation; however, they need to be aware of the damages that might be inflicted upon their scalps. 

The science behind dry shampoos 
   What enables dry shampoos to resemble real “shampoos” is their ability to reduce sebum on one’s scalp for a temporary period of time. The fine powder sprayed from dry shampoos reduces the sebum, an oily substance made by sebaceous glands*** in our bodies. Chemical components that go inside the dry shampoos—rice starch, corn starch, silica, and beta-cyclodextrin—are behind this function. The marketer of CY BioSolutions****, Chang Hong-jae explained in an interview with the Annals, “The rice starch helps absorb scalp sebum and dust particles. After spraying and smoothing a small amount of dry shampoo onto the hair roots, the texture of one’s hair becomes smoother and voluminous due to the absence of sebum.” Corn starch is added to increase the amount of sebum absorbed by dry shampoos. Similarly, when silica and beta-cyclodextrin are applied onto oily or dirty surfaces such as scalp and hair, these chemicals are capable of absorbing oil and dust, just like a sponge. On top of these chemicals, there are propellants—usually butane and propane—that allow the rice starch ingredient to be sprayed evenly on the hair. Although different for every brand, some dry shampoos additionally contain nutrients such as vitamin C, vitamin E, and collagen that strengthen the hair.  
   What to note, however, is that dry shampoos are not hair cleansers like regular shampoos. The biggest difference between dry shampoos and regular shampoos lies in the chemical substances that go into each product. Regular shampoos contain surfactants with hydrophilic and hydrophobic parts that help mix oil and water. The hydrophobic molecules bind to the sebum and any other oil substances on the surface of the scalp, while the hydrophilic molecules are capable of washing away the hydrophobic parts bonded to the sebum. So, the combination of these two types of molecules inside liquid shampoos eliminates oil from the scalp. However, since hydrophobic and hydrophilic molecules are not present in dry shampoos, the scalp sebum are not entirely gone when dry shampoos are sprayed on the hair. According to Lee, “As much as dry shampoos leave the hair seem refreshed, it is hard to say that they can be perfect substitutes for regular shampoos since dry shampoos do not clean the scalp exactly like regular ones do. It is best to think of dry shampoos as products that help keep volume in your hair.” 
   The following are the limitations of using dry shampoos over regular ones. If not washed for long, dry shampoo ingredients can accumulate in the scalp and cause allergies*****. The excess powder causes the skin to become abnormally dry, ultimately drying up the essential moisture needed in the scalp. This leaves the scalp flaky and causes irritation. Another drawback for using dry shampoos without rinsing is that dry shampoos can attract bacteria. If consumers do not rinse their dry-shampooed hair with water for several days, sebum, chemicals from hair products, as well as bacteria all become accumulated in scalp and can altogether lead to dandruff or even fungal infections******. Spraying too much dry shampoo can also weigh down your hair follicles, weakening them, and interrupting their typical growth cycles*******. Hair follicles are vital parts of the scalp as hair starts to grow from the bottom of these follicles. Weakening these hair follicles can ultimately result in hair loss. 

How to use dry shampoos the right way
   According to Lee, there is no set amount of dry shampoo that should be used per day; rather, the amount varies depending on the condition of an individual’s hair and scalp. Those who have exceptionally greasy hair or feel like they lack volume in their hair may apply dry shampoo multiple times throughout the day. Although there is no side-effect to this, there are proper application processes to ensure less damage is done to the hair.  
   Shake the dry shampoo bottle several times before spraying it onto your hair so that all essential ingredients inside the bottle are mixed together.
   It is recommended to spray the dry shampoo twice in small amounts in your roots rather than over-spraying, as even a small amount of dry shampoo can have a visible effect. 
When spraying, the spray itself should be 20 to 25 cm away from the scalp. It is better to divide the hair into multiple sections and then spray the shampoo in between. By doing so, the dry shampoo can be applied evenly throughout the hair roots and not only on the surface. 
After spraying, use a brush or your hand to gently smear the dry shampoo and style your hair the way you want. 
   At the end of the day, it is highly recommended to wash out the excess powder substances using a regular shampoo. 
   Also, rather than using dry shampoos for cleansing purposes, it is better to use them for styling just for a short period of time. 
 
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   Dry shampoos are innovative products that provide a comfortable and quick solution for consumers who are busy or lazy to wash their hair every day. However, despite what the name alludes, dry shampoos do not really take up the role of “shampoos” as they merely absorb hair oil for a short amount of time. So, it is important for the consumers to know the right way to use dry shampoos.
 
*Chosun Ilbo 
**Chosun Ilbo 
***Sebaceous glands: A small group of cells in the skin that produce oil 
****CY BioSolutions: A Korean general trade company that launches medicine, health foods, and cosmetics—including the dry shampoo brand Batiste. 
*****Hankook Ilbo 
******Insider 

*******Healthline 

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