Water
The number one solvent in cosmetic formulas. Provides hydration of the upper stratum corneum but does not penetrate into deeper layers.
Evidence by route
Topical application
Water is the base of most cosmetic formulas. On its own it does not restore the barrier: without emollients and occlusives, moisture quickly evaporates from the skin surface.
How to read tiers A–F
- CWeak evidence. In vitro data, open-label studies, or expert consensus
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Oily, Dry, Sensitive, Combination, Normal
About this ingredient
Water (Aqua) is a universal solvent and the base of most cosmetic formulas. It usually sits first on the INCI list, taking up 50-90% of cream, lotion or serum mass. Cosmetics use purified water – demineralised, filtered, free of bacteria and salts. Function. Solvent for water-soluble actives (hyaluronic acid, glycols, extracts, amino acids), carrier for preservatives and pH regulators, medium for emulsions. Creams and lotions are impossible without water. Skin hydration. Local hydration (putting water on skin) gives a moisture sensation only in the first seconds – without subsequent occlusive application water evaporates rapidly and skin becomes drier due to TEWL. True moisturisation requires a three-level strategy: humectant (glycerin, hyaluronic acid), emollient (squalane, niacinamide), and occlusive (dimethicone, petrolatum, ceramides). Alternatives – thermal waters. Avène, La Roche-Posay, Vichy, Uriage, ISDIN use thermal water as a base. Trace element content (selenium, zinc, calcium, copper) may provide mild anti-inflammatory effects, but direct RCT comparisons with ordinary purified water have not shown a meaningful difference (Cazals-Hatem 2018). Safety. Absolutely safe. Safe for all skin types. Pregnancy and lactation – safe. Without restrictions.
Frequently asked questions
Is Water safe during pregnancy?
Water is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Water for?
Water suits: oily, dry, sensitive, combination, normal.
What is Water and what does it do in cosmetics?
The number one solvent in cosmetic formulas.
What's the INCI name for Water?
The INCI name is Aqua. It may also appear as: Water, Eau, Aqua/Water/Eau.
See Water in a product composition right on the store page
The Evigrade extension adds an evidence panel to iHerb, Sephora, Druni and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
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