(Chún jìng shuǐ)

Purified water – Technical base used as a solvent and excipient

Purified water, sometimes listed on labels as pure water or purified water, is water that has been processed to remove impurities and make it suitable for pharmaceutical and supplement use. In dietary supplements, it is usually not the main “active” ingredient, but instead serves primarily as a solvent, diluent, or manufacturing excipient.

Characteristics, origin, and composition

Purified water is typically produced from potable water through processes such as distillation, ion exchange, reverse osmosis, or other suitable purification methods. The EMA states that water is the most commonly used excipient in medicinal products, and that the grade selected depends on intended use within a risk-based control strategy. The purpose of purification is to reduce unwanted contaminants and microorganisms so the water is suitable for contact with sensitive ingredients and production systems.

Use in dietary supplements

Purified water is commonly used:

• As a solvent in liquid supplements and oral preparations.

• As an excipient during the production of capsules, tablets, and other non-parenteral formulations.

• As a diluent or carrier to help distribute other ingredients evenly.

• As a technical base in certain topical or liquid formulations.

Everyday use and well-being

For the user, purified water on a supplement label usually has a functional role in the product rather than serving as a standout active nutrient. Its main value is helping a formula remain stable, consistent, and manufacturable. When a label says “pure water,” it usually means the product uses a purified water base, not that water is being positioned as a unique health-active ingredient in that formula.