A new study in Cosmetics reports promising early lab results on a nanoemulsion containing Achillea millefolium, or yarrow root extract, alongside two organic UV filters.
The research, led by a team at the Federal University of Rio de Janeiro and funded by multiple institutions, including the Carlos Chagas Filho Foundation for Research Support of the State of Rio de Janeiro (FAPERJ), explores whether a plant-based ingredient can support antioxidant, brightening, and SPF-boosting effects in a single formulation.
The authors describe this study as the first time a nanoemulsion has been formulated specifically with A. millefolium root extract.
Market demand for multifunctional and natural ingredients
The researchers linked their work to the growing demand for products that address several skin concerns at once.
“The increase in life expectancy has driven the demand for beauty and personal care products,” the authors wrote, explaining that more consumers are looking for ways to manage age-related changes in the skin.
The team also pointed to interest in plant-derived alternatives that may reduce environmental impact.
Conventional formulas can leave “residues harmful to human health and the environment”, the researchers explained, which has helped create momentum for natural actives described as “a promising alternative” in the study.
What the researchers tested
To create the prototypes, the team mixed the root extract into a nanoemulsion at three concentrations.
The study reported that the formulations “exhibited physicochemical characteristics suitable for dermocosmetic use”, including stable texture and a pH close to that of the skin.
The samples also spread well, a key factor in sunscreen performance.
The researchers wrote that the prototypes “demonstrated desirable functional properties, such as appropriate spreadability”, which “favors uniform application”.
What they found in the extract
Testing showed that the extract contained several compounds commonly associated with antioxidant and soothing activity. The extract “confirmed the presence of relevant bioactive compounds”, the authors wrote, “such as alkamides and phenolics, including sinapaldehyde.”
The team then assessed how the extract behaved in lab assays. The researchers reported that the composition was “directly associated with the significant antioxidant activity observed in vitro assays”, and noted a mild brightening effect described as “depigmenting potential through tyrosinase inhibition”.
How the extract affected SPF performance
The prototypes combined the plant extract with octyl methoxycinnamate and DHHB, two organic UV filters.
All versions met the common benchmark of a UVA/UVB ratio above 0.6. When the researchers compared the nanoemulsions with and without the botanical extract, they reported “an increase in SPF values” in the samples containing the plant material.
They added that the result suggested “a synergistic effect between the plant’s bioactive compounds and the chemical UV filters”.
Among the three extract levels, the 0.5 percent version performed best, showing “the highest SPF value, optimal UVA/UVB ratio, and the most desirable critical wavelength”.
Why the findings may matter for formulators
Early lab results indicate that A. millefolium root extract may offer multiple functions without showing cytotoxicity in keratinocytes.
According to the authors, its antioxidant activity and mild brightening effect “supports the safety and multifunctionality of the extract for anti-aging formulations”.
They wrote that the findings also “support the feasibility of using A. millefolium in nanoemulsions with photoprotective purposes”.
Source: Cosmetics
2025, 12, 255. https://doi.org/10.3390/cosmetics12060255
“Development of a Multifunctional Phytocosmetic Nanoemulsion Containing Achillea millefolium: A Sustainable Approach."
Authors: Christiani, T.S. et al.
