Myristyl alcohol is a straight-chain saturated fatty alcohol that is prepared by the hydrogenation of myristic acid. Myristic acid can be obtained from nutmeg, palm kernel oil, and coconut oil. Myristyl alcohol is a white crystalline solid. In cosmetics and personal care products, myristyl alcohol functions as a thickener, emulsion stabilizer, and emollient.
As a thickener, myristyl alcohol adds more body and spreadability to a product. It provides a smooth, glossy appearance, reduces the watery feel of hand and body lotions, and imparts a soft, slightly waxy after feel. Myristyl myristate is also used as a co-emulsifier for it’s emulsion stabilizing benefits. Emulsions 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. Myristyl alcohol can be used to improve the overall emulsion stability while delivering additional benefits not offered through increased emulsifiers. Lastly, myristyl alcohol is often found in creams, lotions, and hair care products because it is an emollient. Emollients work to soften and soothe the skin (or hair) while also acting as occlusive agents.
Arachidyl alcohol is a straight-chain fatty alcohol typically obtained via the hydrogenation of arachidic acid or arachidonic acid, both of which are present in peanut oil. It is a waxy substance that functions as an emollient and thickening agent in cosmetics and personal care products.
As an emollient, arachidyl alcohol works to soften and soothe the skin (or hair) while also acting as an occlusive agent. Upon application, occlusive agents form a protective film on the surface of skin, which helps to prevent evaporation of the skin’s natural moisture. Over time, this increases skin hydration by causing buildup of water in the stratum corneum (the uppermost layer of skin). As a thickening agent, arachidyl alcohol is added to formulations to increase their viscosity, resulting in a product that has a rich texture.
Polyvinyl alcohol (PVA) is a water-soluble synthetic polymer that is used for many different purposes, including papermaking, textiles, and a variety of coatings. In cosmetics and personal care products, polyvinyl alcohol functions as a gel-based thickener, film-forming agent, and binding agent. It is frequently used in peel-off facial masks because of its ability to dry into a thin film on the surface of skin that can easily be peeled off. Polyvinyl alcohol can cause skin irritation unless it is combined with other ingredients that protect the skin, such as emollients or skin-repairing ingredients.
Lanolin, also known as wool wax or wool grease, is a wax secreted by the sebaceous (oil) glands of wool-bearing animals. Lanolin used by humans is obtained from domestic sheep breeds that are raised specifically for their wool. Hydrolysis of lanolin yields lanolin alcohol, an ingredient that has been used extensively in skin care products for over 100 years. One function of lanolin alcohol is to act as an emulsifier by keeping the water and oil parts of an emulsion from separating, generally forming w/o (water-in-oil) emulsions.
Lanolin alcohol is also very beneficial to the skin due to its high concentration of cholesterol, a type of lipid molecule. Cholesterol is a natural component of the stratum corneum, making up about 25% of the skin’s lipid barrier. Cholesterol levels in the skin begin to decrease with age, and also from routine exposure to sensitizing ingredients like drying cleansing agents and denatured alcohol. When the skin lacks cholesterol, it can appear dry, flaky, and damaged. Topical application of lanolin alcohol can help to replenish the skin’s cholesterol levels. The result is improved barrier function and increased skin hydration. Those with delicate, sensitive, and dry skin types will likely benefit most from products that contain lanolin alcohol.
Isopropyl alcohol, also known as rubbing alcohol, is a colorless, flammable chemical compound with a strong odor. In cosmetics and personal care products, isopropyl alcohol functions as a solvent by helping other ingredients dissolve into a solution. Solvents can be used to thin out a formulation, which makes the product easier to spread. Solvents can also increase the efficacy of active ingredients in a formulation by enhancing their absorption through the skin. Lastly, isopropyl alcohol offers products a quick-drying finish and immediately degreases skin.
While isopropyl alcohol does provide several benefits to a cosmetic formulation, there are some drawbacks with this ingredient. For instance, since isopropyl alcohol is a volatile alcohol, it can cause side effects such as skin dryness, irritation, and a weakened skin barrier. When the barrier is weakened, things like allergens, bacteria, and irritants can enter the skin and cause damage. Plus, a weakened barrier allows moisture to escape, which can lead to dry, flaky skin. Furthermore, products that contain isopropyl alcohol can be appealing to those with oily skin because of its degreasing effects. However, stripping the skin of its natural oils can actually lead to increased oil production, resulting in shiny skin and breakouts.
C14-22 alcohols is a mixture of synthetic fatty alcohols with 14 to 22 carbons in the alkyl chain. In cosmetics and skin care products, C14-22 alcohols functions as an emulsion stabilizer. Emulsions 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. An emulsion stabilizer like C14-22 alcohols can be used to improve the overall emulsion stability and prevent the oil and water phases from separating.
SD Alcohol 40
SD alcohol 40 is a type of denatured alcohol used in cosmetics and personal care products. The “SD” is an abbreviation for “specially denatured”, which means that a denaturant has been added to the ethanol. This is done to avoid alcoholic beverage taxes in the United States since ethanol is the same kind of alcohol found in beer, liquor, wine, etc. Adding a denaturant makes the ethanol taste unpleasant, thus creating alcohol that is not suitable for drinking, but is otherwise similar for other purposes. The “40” in the ingredient name indicates the type of denaturing method used.
In cosmetics and personal care products, SD alcohol 40 functions as an anti-foaming agent, astringent, antimicrobial agent, and a solvent. SD alcohol 40 can often be found in soaps and hand sanitizers labeled as “antimicrobial” because it has strong bactericidal and fungicidal activity. As an astringent, SD alcohol 40 helps to temporarily tone and tighten the skin, as well as degrease oily skin. Lastly, SD alcohol 40 functions as a solvent to help other ingredients dissolve into a solution. Solvents can also thin out formulations, which makes them easier to spread.