A new study shows that blends of lavender essential oil and hydrosol can replace synthetic preservatives in oil-in-water creams, cutting microbial counts by >99 % without irritating skin.

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Synthetic parabens and formaldehyde releasers are falling out of favour, but keeping creams safe from microbes remains a challenge. The global shift toward “clean-label” cosmetics has left formulators scrambling for milder preservatives.

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A research paper led by Dr Maria Trapali of the University of West Attica, Greece, now offers a drop-in solution: the simple pairing of Lavandula angustifolia hydrosol with its own essential oil.

Using standard O/W emulsions, the researchers challenged products with high loads of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans.

The findings

After 12 weeks at 25 °C and 40 °C, emulsions containing 0.05 % hydrosol + 0.05 % essential oil kept counts below 10 CFU/mL—well inside European Pharmacopoeia limits. In contrast, an unpreserved control passed 10⁵ CFU/mL within four weeks.

Six O/W 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. The authors also provide a rapid GC-MS protocol to ensure consistent linalool levels across lavender chemotypes.

The work is the first to document a true synergy between lavender hydrosol and essential oil, outperforming either agent alone.

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