The main solvent or carrier in many cleansers, lotions and serums.
Sources: 1, 2Aqua, Eau, H2O
Not assessed
No pregnancy- or breastfeeding-specific assessment has been completed for this record. A cosmetic safety review is not a pregnancy rating.
Not assessed
Aqua
What it does
Dissolves compatible ingredients and forms the water phase of a formula. Being first on a label does not establish that a product is ineffective or unusually hydrating.
Sources: 1, 2Good for
- Water-phase formulation
- Dissolving compatible ingredients
How to use it
Use the finished product as directed. Do not dilute a cosmetic with tap water, which changes preservation and may introduce contamination.
Sources: 1, 2Who should be careful
Water is not a treatment or a substitute for a preserved moisturizer. A water-based product may still irritate because of its other ingredients or microbial contamination.
Sources: 1, 2Pairs well with
No supported pairings have been documented for this record.
Usage, safety and formulation details
Mechanism of action
Water's polarity supports dissolution of many ionic and polar ingredients. Persistent skin hydration also depends on the formula's humectants, emollients and film-forming behavior.
Sources: 1, 2Potential adverse effects
A contaminated or otherwise unsuitable water-based formula can cause problems; these should not automatically be attributed to the water molecule.
Sources: 1, 2Formulation considerations
Water quality, manufacturing hygiene, packaging and microbial control matter. A water-containing product needs appropriate preservation or another validated means of controlling contamination.
Sources: 1, 2Pregnancy and breastfeeding
Not assessed
No pregnancy- or breastfeeding-specific assessment has been completed for this record. A cosmetic safety review is not a pregnancy rating.
Safety tags
- Fragrance allergen
- Not assessed
Not separately assessed in this draft.
- Essential oil
- Not assessed
Not separately assessed in this draft.
- Drying alcohol
- Not assessed
Not separately assessed in this draft.
- May irritate sensitive skin
- Not assessed
Not separately assessed in this draft.
What remains uncertain
- Exact concentration, final pH and the full composition of any unprovided finished product
Clinical evidence and research
Clinical evidence
Evidence for its main benefitNot assessed
The cited references support identity, formulation role or safety context. No standalone clinical efficacy rating has been completed for the main benefit in this draft.
Sources: 1, 2Regulation and ingredient label names
Regulatory information
No jurisdiction-specific assessment is recorded. An inventory listing is not blanket approval.
Names on ingredient lists
aqua, water, eau
Chemical identity and molecular structure
Chemical information
Chemical structure
| Detail | Value | Source |
|---|---|---|
| PubChem CID | 962 | PubChem compound 962: chemical identity |
| molecular formula | H2O | PubChem compound 962: chemical identity |
| molecular weight | 18.015 g/mol | PubChem compound 962: chemical identity |
Content updated 9 November 2026.
Sources (3)
Scientific sources
- PubChem: Water chemical identitychemical identity
- FDA: Microbiological safety and cosmeticssafety guidance
- PubChem compound 962: chemical identitychemical identity
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