Water in Cosmetics — Why Is Aqua Listed First?

Aqua — the most common ingredient in cosmetics

If you've ever read the INCI ingredient list on a moisturiser, toner, shampoo or shower gel, there's a very good chance you saw Aqua (or Water) right at the top. This is no cause for concern — it's a natural consequence of how most cosmetics are formulated.

In this article we explain the role water plays in cosmetics, what its position on the INCI list means, what the "waterless beauty" trend is all about, and why the marketing of thermal water deserves a critical eye.

The order on the INCI list — what does it mean?

Under EU regulations (Regulation 1223/2009), ingredients on the INCI list are listed in descending order of concentration — from the ingredient present in the largest amount to the smallest. Ingredients present at concentrations below 1% may be listed in any order at the end of the list. Find out more in our ingredient encyclopaedia.

Aqua in first place simply means that water makes up the largest percentage of the formula — typically 60–85% in creams, 70–90% in toners and 75–90% in shampoos. You can read more about how to read an INCI list in our guide to a cosmetic's ingredient list.

The role of water in a cosmetic formula

Water in a cosmetic is not a "filler" — it serves several key functions:

• Solvent — it dissolves hydrophilic ingredients (hyaluronic acid, niacinamide, glycerin, AHA/BHA acids in salt form).
• Carrier — it delivers active ingredients to the skin.
• Continuous phase of an emulsion — in O/W (oil-in-water) creams, water forms the continuous phase in which droplets of oil are suspended. It's the water that gives popular creams and lotions their light, fast-absorbing texture.
• Consistency control — the amount of water determines whether the product is a thick cream, a light fluid or a runny toner.

Without water it would be impossible to formulate emulsions, gels, toners or most cleansing products. It is a fundamental building block of cosmetic technology.

Thermal water — marketing vs reality

Thermal water (e.g. Avène, La Roche-Posay, Vichy) is promoted as an ingredient with special properties — soothing, mineralising and barrier-strengthening. How does that hold up from a scientific standpoint?

Thermal waters do indeed differ in mineral composition from ordinary purified water. They may contain selenium, silicon, calcium, magnesium and zinc in varying proportions. Some studies (mostly sponsored by manufacturers) have shown a soothing effect of thermal water on skin affected by atopic dermatitis.

Still, it's worth keeping things in perspective:

• The minerals in thermal water are present in trace amounts — their concentration is many times lower than in dedicated cosmetic raw materials.
• In a cream, thermal water performs the same function as purified water — it acts as a solvent and the continuous phase of the emulsion.
• A thermal water spray applied to the skin without subsequently sealing it in (with a cream or oil) can actually lead to paradoxical drying — the water evaporates and carries moisture away from the skin with it.

The takeaway: thermal water in a cream isn't harmful, but it doesn't justify a significant difference in price. What matters is the rest of the formula.

Waterless beauty — the anhydrous cosmetics trend

In recent years, anhydrous (waterless) cosmetics have grown in popularity. Water-free formulas include, among others:

• Oils and oil-based serums — pure plant oils or their blends with oil-soluble active ingredients (retinol, vitamin E, squalane).
• Balms and butters — based on waxes and shea/cocoa butter.
• Powders and powdered cosmetics — e.g. enzymatic powder exfoliants, dry shampoos.
• Sticks — deodorants, lip balms, stick moisturisers.

Advantages of anhydrous formulas

• No need for preservatives — bacteria and fungi need water to grow. An anhydrous formula is inherently less prone to microbial contamination, which eliminates the need to add preservatives. You can read more about this in our article on parabens and preservatives.
• Higher concentration of active ingredients — when water doesn't take up 70–80% of the formula, more room is left for active substances.
• Smaller environmental footprint — lighter transport, smaller packaging, no need to ship water around.

Limitations of anhydrous formulas

• Not all active ingredients are oil-soluble — hyaluronic acid, niacinamide and vitamin C (in the form of ascorbic acid) require a water phase.
• An oily texture doesn't suit every skin type — people with oily skin may prefer light O/W emulsions.
• Anhydrous formulas don't moisturise in the sense of supplying water — they nourish and limit TEWL (transepidermal water loss).

Does water in first place mean a poor cosmetic?

Absolutely not. Water as the dominant ingredient is a technological norm, not a sign of low quality. A cosmetic's effectiveness is determined by its active ingredients (even at concentrations of 1–5%) and the quality of the formula — not by whether water makes up 70% or 75% of the product.

By the same token, an anhydrous cosmetic isn't automatically better. What's crucial is matching the formula to your skin's needs and the presence of effective active ingredients at the right concentrations. You can check the ingredients of specific products in our search engine.

Summary

Aqua at the top of the INCI list is the standard, not a flaw. Water performs the fundamental function of solvent and carrier for active ingredients. The waterless beauty trend has its merits (no preservatives, higher concentrations of actives), but it doesn't mean that water-based products are inferior. The key is to understand the role of each ingredient — rather than judging a cosmetic by whether Aqua comes first.

Analyse your cosmetic's ingredients →