Thermal spring water is interesting stuff. Packed with nutrients and trace elements, certain types of thermal water can soothe stressed or traumatized skin the way regular water just can't.
Spring water from the La Roche-Posay and Avène regions in France is particularly therepeutic, used entirely without additives -- yes, just the pure, uncontaminated water specially piped in from the original springs -- to treat severe cases of psoriasis, atopic dermatitis (eczema) and burns. Treatment at each brand's thermal-station facility (like a medical spa) is so effective that it's covered by France's national healthcare plan.
Both companies formulate their skincare lines with pure thermal water from their respective and exclusive natural springs, as well as produce spray tins of the pure water. Wonderful facial refreshers in hot, humid weather, thermal spring water sprays can also function as anti-inflammatory moisture boosts when spritzed over dry skin (leave on for a few seconds then lightly dab off excess) just before moisturizer.
In a way, thermal water gives new meaning to the term "water works."
UPDATE: Here's a great scientific explanation of thermal water from Michelle – she has a PhD in Chemistry – over at LabMuffin.com.
La Roche-Posay Thermal Spring Water ($13.50 CAN) and Avène Thermal Spring Water ($15 CAN) are available at most major drugstores and pharmacies.