As consumer product preferences and changing EU regulations put pressure on cosmetics formulators to move away from certain long-used synthetic ingredients, this discovery could offer a promising new approach to protect cosmetic formulations from microbial contamination.
Lavender shows promise as natural preservative in cosmetics
The research paper, published in the Journal of Dermatologic Science and Cosmetic Technology by a team of Greek scientists investigated the use of Lavandula angustifolia hydrosol combined with its essential oil as a drop-in solution to preserve product shelf life.
Using standard oil-in-water emulsions, the researchers challenged the formulations with high loads of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans.
After 12 weeks at 25°C and 40°C, emulsions containing 0.05% hydrosol plus 0.05% essential oil maintained microbial counts below 10 CFU/mL, which complies with European Pharmacopoeia limits.
Six different oil-in-water emulsions were stored at 25°C and 40°C for 12 weeks. Products containing 0.05% lavender essential oil plus 0.05% hydrosol remained below 10² CFU g⁻¹, while an unpreserved control exceeded 10⁴ CFU g⁻¹ by week four.
Overall the sample containing both L. angustifolia hydrosol and essential oil demonstrated the best performance. The researchers noted that “by adding the essential oil, antimicrobial activity was significantly enhanced compared to the hydrosol alone, decreasing the population of E. coli from an initial concentration of 9.8 × 10⁶ CFU/mL to 10 CFU/mL."
Meanwhile, Pseudomonas aeruginosa decreased from 3.4 × 10⁵ CFU/mL to fewer than 10 CFU/mL. Staphylococcus aureus decreased from 6.9 × 10⁶ CFU/mL to fewer than 10 CFU/mL, while the Candida albicans population was reduced from 2.0 × 10⁶ CFU/mL to 10 CFU/mL.
The researchers concluded that the combination of hydrosol and essential oil resulted in “significantly superior antimicrobial efficacy, suggesting a rather possible additional synergistic effect compared to the hydrosol alone, surpassing the criteria B set by the European Pharmacopoeia.”
M Trapali et al., Evaluation of the efficacy of lavender formulations as preservative agents in O/W (oil-in-water) emulsions, Journal of Dermatologic Science and Cosmetic Technology (2025).
