Betaine is a natural substance that has a history that dates back to the 19th century when it was discovered in sugar beets.

(Betazz vulgaris). Over the years it has been sourced from other plants such as wheat bran, wheat germ and spinach. It can also be derived from aquatic creatures. It's similar to glycerin in some ways but its a far more potent humectant. 

Functions

The function of betaine depends on how it is produced. Synthetically produced betaine, such as cocamidopropyl betaine, functions as a surfactant. Natural betaine, which is obtained from the process of making sugar out of sugar beets by chromatography of the molasses, functions as an osmolyte.

Osmolytes are compounds that affect osmosis, the process in which a solvent moves across a selectively permeable membrane separating two solutions of different concentrations . This function of betaine is particularly important for skin cells that are dehydrated or exposed to UV radiation. Furthermore, the ability of betaine to increase skin hydration has been shown to have an anti-wrinkle effect.

Ongoing studies have shown betaine can also improve tight skin junction integrity. Tight junctions are protein complexes that prevent leakage of solutes and water between the cells. Tight junctions have been suggested to contribute in the prevention of penetration of harmful substances, such as allergens, pollutants, etc. into the skin. Additionally, tight junctions aid in preventing water loss through the skin. Therefore, by improving tight junction integrity, betaine increases the hydration status of the skin and also protects the skin from harmful environmental substances.

The high water retention capability of betaine makes it an ideal ingredient for hair care products. One study found that the increase of water retention into the hair treated with betaine was 40% by average, compared to hair treated with glycerol at only 6%. Furthermore, when betaine is added to hair conditioners it has been shown to improve the hair feel and the ease of wet/dry combing. Overall, the addition of betaine to hair care products gives the hair more strength and hydration, as well as makes the hair shiny and more elastic.

Betaine also functions as a texture enhancer in cosmetics and personal care products. It is known to provide a silky feel to skin care preparations without causing tackiness. Betaine also has the ability to increase the swelling speed of some hydrophilic thickeners and enhancers their thickening power by 20% on average. Additionally, when betaine is added to formulations containing surfactants, it has been shown to increase foam volume and reduce irritation potential of surfactants. This property of betaine is ideal for shampoos, especially when used to formulate a delicate, easy-rinse baby shampoo that contains a low amount of surfactants.