O-cymen-5-ol is used in a wide range of cosmetic formulations, from creams and compact powders to shampoos. But what exactly is it and why is it used in cosmetics?
What is "O-Cymen-5-ol" and what is its purpose?
O-cymen-5-ol: What is it and what is its role?
O-cymen-5-ol (C10H14O), also known as 4-isopropyl-m-cresol, is a substituted phenolic compound. It was first synthesised in 1954 as a homologue of thymol. O-cymen-5-ol (MW = A50 g/mol) presents itself as a colourless and odourless crystalline solid. It is also stable in light and barely soluble in water. However, o-cymen-5-ol readily reacts with oxidising agents to form methyl-bridged dimers and quinone dimers. The European cosmetic regulation permits the use of o-cymen-5-ol at a maximum concentration of 0.1%.
What is its utility in cosmetic products?
O-cymen-5-ol is primarily used in cosmetic formulations as a preservative. It possesses antibacterial and antifungal properties. Indeed, it counteracts the growth of microorganisms in cosmetic products, thereby increasing the shelf life and maintaining the consistent quality of the product.
Studies have demonstrated the ability of o-cymen-5-ol to inhibit the growth of a variety of bacteria, yeasts, and fungi, including Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Bacillus subtilis, Staphylococcus aureus, Aspergillus niger, Penicillium citrinum, etc. It even has superior antifungal efficacy compared to many traditional preservatives. According to research, it is a very good substitute for triclosan.
As an antimicrobial agent, this ingredient also serves to destroy or inhibit the growth of harmful microorganisms on the skin. Similarly, when added to oral care products (toothpastes, mouthwashes...), it helps to slow down processes related to the development of periodontal diseases, that is, to combat dental plaque/gingivitis. O-cymen-5-ol is also included in the formulation of skincare products for its deodorising properties (masking agent). This ingredient masks or reduces odours by combating harmful bacterial agents present on the skin.
The o-cymen-5-ol used in our treatments is synthetically derived and originates from China.
O-cymen-5-ol: What is its cytotoxic profile?
The expert group from the CIR has concluded that o-cymen-5-ol can be safely used in cosmetic products at the recommended concentration (≤ 0.1%). However, rare cases of allergic reactions may be observed (irritation, redness, etc.). Furthermore, o-cymen-5-ol has been deemed neurotoxic to animals in certain Japanese scientific studies dating back to 1956, leading to usage restrictions in cosmetics in that country. Yet, further investigations are necessary to confirm this claim, not forgetting the fact that the obtained data must be transposed and validated in humans. O-cymen-5-ol remains one of the most widely used preservatives in cosmetics.
Final report on the safety assessment of o-cymen-5-ol. Journal of the American College of Toxicology (1984).
ANDERSEN A. Final report on the safety assessment of sodium p-chloro-m-cresol, p-chloro-m-cresol, chlorothymol, mixed cresols, m-cresol, o-cresol, p-cresol, isopropyl cresols, thymol, o-cymen-5-ol, and carvacrol. International Journal of Toxicology (2006).
BRADSHAW D. J. & al. Antimicrobial effects of o-cymen-5-ol and zinc, alone & in combination in simple solutions and toothpaste formulations. International Dental Journal (2011).