Thermal water: what it is, which minerals it contains, and why it soothes

[INDICE:h2]

Thermal water is neither bottled mineral water nor scented distilled water. It is water that emerges hot from underground after traveling through rocks for years, and along the way it acquires a mineral composition that cannot be replicated in a laboratory.

This guide explains what it is and why it works on the skin. If, instead, you are looking for a comparison of the LeLang formulas and advice on which one to choose, you can find it in the article on which thermal water spray to use and when.

What is thermal water?

Thermal water is defined as groundwater that emerges at a temperature higher than the average ambient temperature and has a distinctive and consistent mineral composition, recognized from a regulatory standpoint. Temperature alone does not define it: it is the combination of deep origin, compositional stability, and the presence of dissolved minerals.

Rainwater that seeps into the ground takes years, sometimes decades, to pass through layers of rock. Along the way, it warms due to the geothermal gradient and dissolves minerals from the rocks it encounters. This is why two springs just a few kilometers apart can have completely different profiles.

Minerals and what they do for the skin

The composition varies from spring to spring, but some elements recur and have a recognized role in skincare.

The role of pH

Many thermal waters have a neutral or alkaline pH, while healthy skin has a slightly acidic pH, between 4.5 and 5.5. It may seem contradictory, and it is worth explaining: contact is brief, and the skin’s buffering capacity quickly restores its own pH. This is one reason thermal water should be gently patted dry and followed by a product, rather than left to air-dry.

Why it soothes reddened skin

The most noticeable effect is the soothing one, and it depends on three factors that work together.

The first is thermal: misting a room-temperature liquid onto warm skin produces cooling through evaporation, reducing superficial vasodilation. It is the same principle behind the effectiveness of cold compresses for swelling.

The second is mineral: the dissolved trace elements interact with the skin's surface, contributing to a feeling of comfort and supporting antioxidant defenses.

The third is the absence of irritants. Thermal water contains no surfactants, fragrances, or alcohol: on already stressed sensitive skin, adding nothing is itself a benefit.

It should be stated clearly: thermal spray water is a soothing cosmetic. It relieves reddened or stressed skin, but it does not treat eczema, psoriasis, or other skin conditions, for which a dermatologist remains the point of reference.

The mistake that cancels out its effect

This is the most important point in the entire guide, and the least well-known. If you mist thermal water and let it evaporate on its own, the net effect on hydration is negative: as it evaporates, the water also carries away some of the moisture present in the stratum corneum.

The correct routine has three steps: mist from twenty to thirty centimeters away from your face, pat away the excess with your hands or a tissue without rubbing, and immediately apply a product that seals in moisture — a serum or cream. Without the third step, thermal water refreshes and does nothing else.

LeLang thermal waters

Our waters come from the springs of the Royal Spas of Valdieri in Piedmont: hyperthermal sulfurous-sulfate-bicarbonate-sodium mineral thermal springs, with water that emerges at around 60 degrees. They are rich in magnesium, iron, calcium, potassium, and zinc.

Two formulas with different goals stem from this base — Multi Vit, vitamin-rich and soothing, and Pro Age, antioxidant and hydrating. The full comparison, including guidance on which to choose based on your skin, is in the dedicated article about which thermal spray water to use.

MULTI VIT THERMAL WATER Soothing thermal water spray Soothes, protects, strengthens the skin barrier Soothes skin inflammations Soothing eff... Discover MULTI VIT THERMAL WATER

Frequently asked questions about thermal water

What's the difference between thermal water and micellar water?

They do opposite things. Micellar water is a cleanser: it contains surfactants that capture dirt and makeup and must be rinsed off or removed. Thermal water does not cleanse anything: it provides minerals and relief, and is used after cleansing, not instead of it.

Does thermal water really hydrate?

It contributes to surface hydration, but only if followed by an occlusive product. On its own, it evaporates, and as it evaporates it draws moisture away from the skin. It is an excellent prep step for subsequent products, not a moisturizer on its own.

Can it be used every day?

Yes, even several times a day. It contains no active ingredients that accumulate or substances that cause sensitization with repeated use. The only precaution is to pat the skin dry and seal in the moisture.

Is it suitable for children?

It depends on the product. Pure thermal waters, made solely from spring water, are often indicated for use by children as well, according to the manufacturer's instructions. Waters formulated with added active ingredients such as vitamins, hyaluronic acid, and plant extracts—including ours—are cosmetics intended for adult skin and have not been tested on children under 3. For a child's skin, the appropriate reference is their pediatrician.

Should it be stored in the refrigerator?

Yes, but to enhance the immediate effect, not to extend its shelf life: the cold intensifies vasoconstriction and therefore relief from redness and the sensation of heat. It is particularly useful in summer and for reactive skin.

Does thermal water expire?

Like all cosmetics, it has an expiration date indicated on the packaging. Spray formats are generally pressurized and not exposed to air, which preserves their integrity; after opening, however, the PAO indicated on the bottle still applies.

Sources

• Composition of the mineral and thermal springs at the Royal Spa of Valdieri, classified as hyperthermal sulfurous-sulfate-bicarbonate-sodium water.
• INCI name for thermal water: Thermal Water or Aqua with the spring indicated, CosIng database of the European Commission.