Humectants

Humectants are substances commonly used in hair care products to help the hair retain moisture. They work by attracting water molecules from the air and binding them to the hair strands, keeping the hair hydrated and healthy.  The process by which humectants bind water to the hair is known as hygroscopicity.

 

In addition to their ability to bind water, some humectants can also help to slow down the evaporation of water from the hair by forming a protective barrier on the hair strands that can reduce the rate of water loss. Humectants are usually categorized based on their chemical structure and origin, here are the general categories:

 

Sugar alcohols:  also known as polyols, include ingredients such as sorbitol, maltitol, xylitol, and glycerol. They are derived from natural sources such as fruits and other plant products.  

 

Alpha hydroxy acids (AHAs): AHAs are water-soluble organic acids found in many fruits and dairy products. They include lactic, mandelic, and glycolic acids. 

 

Hydrolyzed Proteins: Certain proteins, such as hydrolyzed keratin and silk protein, have humectant-like properties due to their ability to attract moisture to the hair and improve elasticity and strength.

 

Natural extracts: These include aloe vera, honey, and seaweed extract, as they help to attract and retain moisture in the hair.

 

Synthetic polymers: Examples are polyethylene glycol (PEG) and propylene glycol which are typically derived from petroleum oil. They are effective at attracting and retaining moisture but can be drying if used in high concentrations.

 

Overall, humectants play an important role in hair care by helping to attract and retain moisture in the hair. By improving the hair's moisture retention capacity and increasing its elasticity and strength, humectants can help to promote healthy hair growth and prevent damage and breakage.