Hydrogenated lecithin is an ingredient that functions as an emollient, emulsifier, and penetration enhancer in cosmetics and personal care products.
Lecithin is a generic term that describes any group of yellow-brownish fatty substances that naturally occur in plant and animal tissues, as well as in the human body. Lecithin was first isolated in 1845 by the French chemist and pharmacist Theodore Gobley from egg yolk. It can also be derived from sources such as soybeans, milk, marine sources, rapeseed, cottonseed, and sunflower. It’s made up of fatty acids, typically a mixture of the diglycerides of stearic, palmitic and oleic acids, linked to the choline ester of phosphoric acid. Lecithin fats are amphiphilic, which means they attract both water and fatty substances (they are hydrophilic and lipophilic).
The use of lecithin in cosmetics and personal care products was previously limited because of its oxidation and instability against heat. This is why hydrogenated lecithin was created. Hydrogenated lecithin is the product of controlled hydrogenation (addition of hydrogen) of lecithin. Hydrogenated lecithin provides all of the same benefits of natural lecithin, but it has improved stability.
In cosmetics and personal care products, hydrogenated lecithin functions as an emollient, emulsifier, and penetration enhancer.
As an emollient, hydrogenated lecithin has the ability to soften and soothe the skin. Its high concentration of fatty acids creates a protective barrier on the skin that effectively seals moisture in while keeping environmental elements out. This property makes hydrogenated lecithin an excellent ingredient to add to restorative creams, or in products designed for mature, dry, or overworked skin. Additionally, hydrogenated lecithin is commonly used in hair conditioners and other hair products due to its emollient properties.
Hydrogenated lecithin also functions as an excellent emulsifier. Emulsifiers are needed for products that contain both water and oil components. Mixing water and oil together creates a dispersion of oil droplets in water (and vice versa). However, these two phases can separate if the product is left to settle. To address this problem, an emulsifier like hydrogenated lecithin can be added to the system to help the droplets remain dispersed. Emulsifiers improve the consistency of a product, which enables an even distribution of topical skin care benefits.
Hydrogenated lecithin can also be classified as a penetration enhancer. This means it has the ability to deeply penetrate through the layers of skin, enhancing the penetration of other active ingredients. In aqueous solution, its phospholipids can form liposomes, spherical structures in which the acyl chains are inside and not exposed to the aqueous phase. According to an article published in the International Journal of Toxicology, liposomes are considered effective in capturing other compounds inside their spherical structure and delivering these compounds through the skin barrier.
The safety of lecithin and hydrogenated lecithin has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The Panel evaluated the scientific data and concluded that lecithin and hydrogenated lecithin are safe as used in rinse-off products. However, the Panel limited the use of lecithin and hydrogenated lecithin in leave-on products to concentrations less than or equal to 15 percent.
Since hydrogenated lecithin functions as a penetration enhancer, caution should be exercised when it is combined in formulations with other ingredients that may be harmful if absorbed through the skin.
It is possible for some people to have allergies to hydrogenated lecithin since it can be derived from soybeans, eggs, and milk, which are common allergenic foods. Those that are highly sensitive to these foods might react to hydrogenated lecithin.
References: Wikipedia “Lecithin”, Toxic Free Foundation “Hydrogenated Lecithin”, Healthline “Lecithin Benefits”, Int J Toxicol 2001;20 Suppl 1:21-45, Cosmetics Info “Lecithin”, WiseGeek “What are the benefits of lecithin?”