How does Hair Removal Cream Work

Removing body hair is a practise that has been traced back as far as ancient Egypt and India,1,2 where copper razors were used by women to shave their body hair as well as the hair on their head. Hair removal is still just as popular and desirable for many people today, although the methods we use have developed to be much more efficient and safe. For most of us who choose to remove body hair, shaving is too temporary and waxing is too painful, and so hair removal cream seems like a happy middle ground.

The key structural material that makes up strands of hair is keratin, a fibrous protein that contains large amounts of the amino acid cysteine. Since cysteine contains sulfur, the presence of many cysteine residues allows for the formation of disulfide bridges between them. As well as hydrogen bonding between amino acid residues in the hairs structure, these disulphide bonds give hair both rigidity and thermal stability.

Figure 1. The composition of hair.

Hair removal creams work by breaking down disulfide bonds, often using a chemical called calcium thioglycolate. The thioglycolate salt breaks the disulfide bonds in keratin, breaking down the structure of the hair in the process. Once these bonds are broken, the hair becomes weak and can be removed from the skin by simply wiping and rinsing off the cream with water.

Figure 2. The mechanism of disulfide bond breakage upon addition of hair removal cream to the skin.

The composition of hair removal creams is usually around 5% of the active thioglycolate ingredient mixed with a variety of other chemicals. Metal hydroxides such as NaOH and Ca(OH)2 are usually present in the cream to help to adjust the pH levels to allow the active acid to react with cysteine residues in the hair.3, 4 Hair removal creams also contain a substantial amount of water which is used as a solvent to dilute and dissolve all the ingredients, creating a cream with a consistency that is easy to spread onto the skin. Emollients are also incorporated into the cream to help soothe the skin after application and reduce any sort of reaction to the harsher chemicals present in the product. These emollients are usually oils and silicones which help to repair the skin after chemical hair removal.3

On paper, hair removal creams sound like the ideal solution to achieving hairless skin, but they do not come without their own problems. Skin itself contains keratin and so if you leave hair removal cream on for longer than advised, the cream can start to break down these proteins irritate the skin. Customers are advised not to use any abrasive or rough objects like exfoliating gloves on the skin after using hair removal creams, but to apply moisturising creams with ideally a high water content to help soothe the skin. Since irritation is one of the main concerns, developments into the incorporation of less hazardous active ingredients has become vital, and creams that adhere to specific skin types are now available.

Whichever way you choose to remove body hair, make sure you patch test creams to minimise the possibility of your skin reacting to the cream. Remember- body hair is completely natural and if you don’t want to remove it, you don’t have to!

References

  1. J. Shrivastava, A History of Body Hair Removal and Distorted Body Image, 2018, available from: https://feminisminindia.com/2018/05/16/history-body-hair-removal/
  2. Women’s Museum of California, The History of Female Hair Removal, 2017, available from: https://womensmuseum.wordpress.com/2017/11/22/the-history-of-female-hair-removal/
  3. C. Ochs, Ingredients in Hair Removal Creams, 2010, available from: https://www.livestrong.com/article/144535-ingredients-in-hair-removal-creams/
  4. A. M. Helmenstine, How Chemical Hair Removal Works, 2019, available from: https://www.thoughtco.com/how-chemical-hair-removal-works-3975982

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