Hydrolyzed Chestnut Extract

Hydrolyzed chestnut extract is derived from chestnut plant material, typically the astringent skin of the fruit. It is rich in ellagitannins — a class of polyphenolic compounds known for their antioxidant and antimicrobial properties. The hydrolyzed form means the larger molecules have been broken down into smaller, more permeable components that can penetrate the skin barrier.

In skincare formulations, this ingredient is classified as a skin protectant. Its tannin content gives it astringent properties, and preliminary research suggests it may offer both anti-inflammatory and antimicrobial benefits relevant to problematic skin conditions.

Hydrolyzed chestnut extract works primarily through its high concentration of ellagitannins, a type of polyphenol. These compounds interact with proteins in the skin and can inhibit inflammatory signalling pathways — specifically, they appear to suppress the release of inflammatory cytokines (IL-8 and IL-6) that drive acne and redness. This action occurs without activating other inflammatory pathways, suggesting a targeted mechanism.

The tannin molecules also have antimicrobial and anti-biofilm properties, meaning they may help prevent bacterial colonisation and reduce the formation of protective biofilms that bacteria develop on skin. Additionally, tannins can cross-link with collagen fibres, potentially contributing to skin strengthening and protection.

Hydrolyzed chestnut extract is typically incorporated into cleansers, toners, serums, and masks. As with any plant extract, introduce it gradually if you have reactive skin. It pairs well with other antioxidants and anti-inflammatory ingredients. As concentration ranges in commercial products are not well standardised, efficacy may vary between formulations.