SODIUM

Sodium ion: Main Effects & Top 5

Published May 5, 2026·1min read

Sodium ion (Na⁺) is the key component of chloride and bicarbonate springs. It forms a thin salt film on the skin, locking in warmth long after bathing.

Table of Contents

What is Sodium ion?
Main Effects
Sodium ion Top 5 Hot Springs

What is Sodium ion?

Sodium ion (Na⁺) is the key component of chloride and bicarbonate springs. It forms a thin salt film on the skin, locking in warmth long after bathing.

Main Effects

Post-bath heat retentionThe salt content in the water forms a thin film on the skin after bathing. This film acts as a barrier, slowing down the dissipation of body heat and helping you stay warm for longer.
Relief from poor circulationThe combined effect of the water's warmth and the heat-retaining salt film may help improve circulation. This synergy helps maintain blood flow to the extremities for a longer period after your bath.
Skin hydrationSalt components adhere to the skin, creating a natural "wrapping" layer. This barrier helps prevent moisture from evaporating from the skin's surface, thus promoting hydration.

Sodium ion Top 5 Hot Springs

Top 5 hot springs registered on this site with the highest content.

RANKING BY THIS MINERAL CONTENT

References

SPRING TYPEMay 5, 2026· 2min read

Chloride Springs: Benefits, Indications & Recommended Onsen

Chloride springs (Cl⁻ as the main anion) are known as "the hot-retaining waters" because the salt coating on your skin keeps body heat from escaping after bathing. Excellent for cold sensitivity and dry skin.

MINERALMay 5, 2026· 1min read

Chloride ion: Main Effects & Top 5

Chloride ion (Cl⁻) is the main component of chloride springs. Like sea salt, it forms a thin film on the skin trapping heat, earning the nickname "hot spring" (熱の湯).

SPRING TYPEMay 5, 2026· 1min read

Simple Springs (Tanjun Onsen): Gentle Waters for Everyone

Simple springs have dissolved components below 1,000 mg/kg and a source temperature of 25°C or above. Mild and non-irritating, they are safe for all ages. Alkaline simple springs (pH 8.5+) are famous for leaving skin silky smooth.