Eau (water) is the most common base ingredient in skincare formulations, serving as a solvent and carrier for other ingredients. It has no therapeutic activity on its own but is essential for dissolving and dispersing actives, humectants, and other components.
| Reported effect | How often | Notes |
|---|---|---|
| Skin irritation | Very rare | Pure water is essentially inert; irritation is typically attributable to impurities or other formula components rather than water itself. |
| Transepidermal water loss disruption | Rare | Excessive exposure to water can transiently disrupt the skin barrier, but this is uncommon in standard cosmetic use. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.