The Index · Solvent vehicle
Water
Aqua / Water / Eau
Primary solvent and vehicle in most skincare; listed as Aqua, Water, or Eau on INCI.
FunctionalFunctional ingredient, not graded for skin benefits
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Primary solvent and vehicle in most skincare; listed as Aqua, Water, or Eau on INCI.
What it does
Dissolves hydrophilic actives and makes up the bulk of aqueous emulsions and serums.
The evidence
Functional ingredient (not graded for skin benefits): Fundamental cosmetic solvent; safety as vehicle is well established. Credible chemical identity and cosmetic-use context come from CIR/SCCS/manufacturer INCI definitions and databases such as SpecialChem/PubChem[1].
How to use it
Expect this as a supporting INCI line item unless labeled as a featured active.
What it does in the formula
Functional ingredient — not graded for skin benefits
Primary solvent and vehicle in most skincare; listed as Aqua, Water, or Eau on INCI.[1]
Safety & limits
Source and region, always
Sources · 2
Numbered as cited in the text
- [1]Cosmetic Ingredient Review. Safety Assessment of Water as Used in Cosmetics context. CIR (2010)regulator
- [2]NIH PubChem. PubChem Compound Summary: Water. PubChem (2024)other
Revision history
18 Sept 2026Drafted by botTheSkindex Desk