Benzyl alcohol is an ingredient that is used in cosmetics and personal care products as a fragrance component, preservative, solvent, and viscosity-decreasing agent.
Benzyl alcohol is a colorless liquid with a mild pleasant aromatic odor. It is produced naturally by many plants and is a minor constituent in foods such as apples, raspberries, strawberries, grapes, peaches, and tea. Benzyl alcohol is also a minor component of many essential oils including jasmine, hyacinth, neroli, rose, and ylang-ylang.
In addition to its natural occurrence, benzyl alcohol can be synthetically prepared by the hydrolysis of benzyl chloride using sodium hydroxide. This was discovered in the 1800s during developments in the coal tar and dye industry. The need for benzyl chloride in dye synthesis led to research into how to improve the hydrolysis of benzyl chloride into benzyl alcohol, benzaldehyde, and benzoic acid. In 1853, it was reported that benzaldehyde would react to caustic and break into equal quantities of benzyl alcohol and benzoate salts.
In cosmetics and personal care products, benzyl alcohol functions as a fragrance component, preservative, solvent, and viscosity-decreasing agent.
Benzyl alcohol functions as a fragrance component when it is used in high concentrations. Since it is part of the fragrance makeup of essential oils like jasmine, hyacinth, neroli, rose, and ylang-ylang, pure benzyl alcohol imparts a floral-like scent to products. However, aged material that is exposed to air will take on a slight benzaldehyde note which, as it develops, changes the impression to fruity and then to almond as the impurities increase in trace amounts.
Benzyl alcohol can also be used as a bacteriostatic preservative in cosmetics and personal care products. The use of preservatives is necessary to prevent microbial contamination, especially since cosmetics have a high potential for contamination. The most susceptible products are creams and lotions that are packaged in jars, opened frequently, and applied to the skin with the fingers. Furthermore, the ingredients used in cosmetic formulations, such as water, oils, peptides, and carbohydrates, plus the warm storage temperatures create the perfect environment for microorganism growth. Microbial contamination can lead to significant health problems, from skin irritation to infections. Preservatives like benzyl alcohol can help to prevent these problems.
As a bacteriostatic preservative, benzyl alcohol works by inhibiting bacterial reproduction, while not necessarily killing them otherwise. This is in contrast to bactericides, which kill bacteria. Since benzyl alcohol cannot kill bacteria, it is typically combined with other preservatives in a cosmetic formulation.
Benzyl alcohol also functions as a solvent in cosmetics and personal care products. Solvents help other ingredients dissolve into a solution. Solvents can be used to thin out a formulation, which makes the product easier to spread. This is why benzyl alcohol can also be classified as a viscosity-decreasing agent. Lastly, solvents can increase the efficacy of active ingredients in a formulation by enhancing their absorption through the skin.
The United States Food and Drug Administration (FDA) has approved benzyl alcohol as an anesthetic ingredient in over-the-counter (OTC) anorectal, oral healthcare, and topical analgesic drug products.
The safety of benzyl alcohol has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The Panel noted that no adverse effects of benzyl alcohol were seen in chronic oral exposure studies, and inhalation exposure to benzyl alcohol did not result in adverse effects. However, clinical data indicated that some people had non-immunologic contact reactions to benzyl alcohol, which were characterized by redness and itching. Recognizing that the non-immunologic reactions were strictly cutaneous, likely involve a cholinergic mechanism, it was concluded that benzyl alcohol could be used safely at concentrations up to 5%. Overall, the Panel concluded that benzyl alcohol was safe for use in cosmetic products.
References: Wikipedia “Benzyl Alcohol”, Perfumer & Flavorist “Benzyl Alcohol” Vol 17 Nov/Dec 1992, Int J Toxicol 2001;20 Suppl 3:23-50, Cosmetics Info “Benzyl Alcohol”