Botanical Hydrosols and the Skin Microbiome

Botanical Hydrosols in Functional Cosmetic Formulations: Potential Effects on the Skin Microbiome

In recent years, cosmetic science has shifted toward formulation approaches that address not only the skin’s surface structure but also the balance of the skin microbiome. Within this framework, hydrosols—or botanical waters—are being evaluated as versatile and milder aqueous extracts that may play a role in maintaining microbiological balance.

Botanical hydrosols are obtained during the distillation process alongside essential oils and contain water-soluble aromatic and bioactive components.

In products that prioritize microbiome-friendly properties, such hydrosols are considered potential contributors to the formulation's overall compatibility with the skin’s natural ecosystem.

The Skin Microbiome: A Delicate Epidermal Ecosystem

The skin microbiome is a complex community of microorganisms. This biofilm layer contributes to the preservation of barrier function and the skin’s adaptation to environmental stressors. Factors such as pH level, sebum production, hydration, and topical treatments can all influence the composition of the microbiome.

Ingredients used in cosmetic formulations that help maintain this biological balance have become a prominent subject of research in formulation science.

Lavandula angustifolia (Lavender Hydrosol)

Derived from Lavandula angustifolia, lavender hydrosol contains compounds such as linalool and linalyl acetate. When applied topically, it is often noted for its refreshing aroma and mild character. Due to its low irritation potential, it has been observed in certain formulations designed for sensitive skin.

Rosa damascena (Rose Hydrosol)

Rose hydrosol, obtained from the distillation of Rosa damascena, naturally contains geraniol, citronellol, and phenylethanol. Beyond its aromatic attributes, it is included in formulas designed to provide moisture. Its slightly acidic nature is thought to support the skin’s natural pH, which may benefit microbiome-friendly applications.

Centaurea cyanus (Cornflower Hydrosol)

This hydrosol, distilled from Centaurea cyanus, contains flavonoid derivatives, coumarins, and trace levels of volatile components. Known for its mild nature, it is commonly observed in eye-area cosmetic formulations. Ongoing research explores its potential soothing effects and relevance in microbiome-conscious skin care.

Hydrosol Selection in Formulation Strategy

Due to their water phase characteristics, botanical hydrosols can be incorporated into functional cosmetic products. Factors such as formulation stability, microbial safety, and target skin type determine which hydrosol is used and in what concentration.

At Greenext, hydrosols are obtained through contract farming models and processed with full traceability. Their potential contribution to microbiome balance continues to be a subject of interest for future clinical research.

Frequently Asked Questions

Can hydrosols be applied directly to the skin?
Due to their diluted nature, they are often observed to be well-tolerated, even on sensitive skin. However, individual skin differences should always be considered.

Do hydrosols disrupt the skin microbiome?
Some studies suggest that natural-source hydrosols do not negatively impact microbiome balance. Still, the overall formulation must be evaluated in full context.

Do products with hydrosols require preservatives?
Yes. For microbiological stability, hydrosol-based products may require preservation systems, which are essential for shelf life and safety.

References

• Callejon, R.M. et al. (2008). Characterization of hydrosols of Rosa damascena. Journal of Agricultural and Food Chemistry.
• D’Amato, G. et al. (2016). The role of the microbiome in dermatology. Clinical Reviews in Allergy & Immunology.