The scientists observed that liquid foundations on the market today required make-up removing cleansers and oils to remove completely. However, they claimed that these actions could damage the skin barrier and lead to skin issues such as sensitivity and rosacea.
“It is imperative to find a new alternative material that avoids the skin barrier damage caused by excessive cleaning.”
To produce an easily removable liquid foundation, the team sought to replace conventional ingredients such as mineral oil and titanium oxide with cellulose derived from hemp.
With the recent legalisation of industrial hemp around the world, more research has been focused on the material.
However, the main substances applied in relevant drugs and cosmetics are usually extracted from hemp flowers and leaves, inadvertently generating plenty of waste in the form of hemp stalks that the researchers believe hold a lot of potential as a cosmetic material.
“As one of the earliest fibres used by human beings, the waste hemp stalks can be reused, which in the meantime can conserve resources and protect the environment. With the natural emulsifying and stabilising characteristics, hemp cellulose is going to play an important role in cosmetics, besides food production and packaging industry.”
These considerations resulted in the development of a hemp cellulose nanocrystals-based liquid foundation.
This novel formula was tested against commercial foundation liquid (CFL) on human subjects and observed through dermascopy.
After wiping with a cotton pad, the residue of CFL on the skin could still be seen clearly, while there was little residue in the skin texture wiping away the hemp cellulose nanocrystals-based foundation.
Subsequently, the subject’s skin underwent deep cleansing with water and make-up removing oil. The researchers observed that the skin texture became unclear and some red spots appeared, suggesting that the skin barrier may have been damaged.
“This further illustrates the importance of easy wiping ability of the foundation liquid for protecting the skin barrier.”
Foundation with multi-benefits
Even though the hemp cellulose nanocrystals foundation can be easily removed, the study accessed the foundation every hour for nine hours after application.
They observed that the new foundation liquid adhered well to the skin surface within nine hours, during which the skin surface was maintained with stable gloss and uniform colours.
The CFL showed similar results, indicating that both formulas had similar adhesion properties.
At the same time, it was observed through VISIA skin analysis that the hemp foundation performed similarly to CFL when it came to coverage of facial pigmentation and acne.
Additionally, the results of the skin individual typology angle (ITA°) showed that the ITA° of the skin was improved from the previous 67 to about 70 after use of the hemp foundation.
From these experiments, the researchers concluded that their new hemp formula met the basic requirements of a foundation solution.
The study also addressed concerns over the safety of the cellulose nanocrystals by conducting a skin penetration experiment using a porcine skin model.
The formulas were marked with fluorescein isothiocyanate isomer (FITC) and the hemp foundation was observed to remain on the surface of the stratum corneum while the CFL demonstrated deeper penetration into the dermis.
Based on the above findings, it was speculated that the hemp/cellulose nanocrystals-based foundation may have protective effects by preventing harmful substances from entering the skin.
Additionally, because of the absorption effect of cellulose, wiping the hemp/cellulose nanocrystals foundation liquid would also remove the excessive oil and air pollutants on the skin surface, just like how cellulose does during the digestion and metabolism in the intestine, researchers said.
“It does not only meet the needs of healthy skin for continuous and healthy use but also brings new benefits to the users whose skin barrier is damaged.”
Source: ACS Omega
"Cellulose Nanocrystals for Skin Barrier Protection by Preparing a Versatile Foundation Liquid"
Authors: Jie Tang et al.
