What is colloidal silver? Particles, ions and PPM explained

August 27, 2026

Colloidal silver, sometimes called “silver water”, is a liquid containing very small silver particles. Depending on how it is produced, it can also contain dissolved silver ions. Two products with the same PPM value are therefore not necessarily the same.

Online descriptions often combine these basic chemical facts with broad health claims. A useful assessment separates the material, its concentration and its intended product category.

What does colloidal mean?

A colloid is a finely dispersed system. Small particles are distributed throughout another substance without being completely dissolved as individual molecules or ions. In colloidal silver, the surrounding liquid is usually water.

The conventional colloidal size range is approximately one nanometre to one micrometre in at least one dimension. Actual silver products can have a distribution of particle sizes and can contain both particles and dissolved ions. A product name alone does not describe that mixture.

Silver has the chemical symbol Ag and atomic number 47. Metallic silver, silver ions and silver compounds have different properties and should not be treated as interchangeable terms.

Silver particles and silver ions

Metallic silver particles contain many silver atoms. Silver ions are electrically charged species that may be dissolved in the liquid. Their relative amounts depend on production, water quality, storage and the methods used to analyse the sample.

A total silver concentration does not reveal particle size, size distribution or the balance between dissolved and particulate silver. These require additional measurements.

What does PPM tell you?

PPM means parts per million. When stated as a mass fraction in a dilute liquid with a density close to water, 10 ppm corresponds approximately to 10 milligrams per litre. This describes total silver only if that is what the analysis measured.

PPM measures concentration. It does not measure particle size, prove quality or establish a health benefit. Samples with identical PPM values can have substantially different compositions.

From terminology to a product comparison

When searching for silver water or colloidal silver, distinguish three details: the name describes the material, PPM describes concentration, and millilitres describe fill volume. A spray head alone does not establish composition or intended use.

Compare concentrations: understand 25, 50 and 100 ppm.
Understand the format: what the name silver spray tells you.
Check packaging: compare amber glass, PET and shelf-life information.

The silver overview links to bottles, sprays and multipacks currently offered. The product label defines the intended use.

How are silver dispersions produced?

Several processes can produce silver dispersions. Electrochemical methods use electrodes and an electrical current to transfer small amounts of silver into water. Other methods use chemical reduction or controlled industrial processes.

The result depends on water and raw-material purity, electrode condition, current, voltage, process time, temperature, storage and analytical controls. These are factors for understanding product quality, rather than a recipe for home production.

Can colour identify colloidal silver?

Silver dispersions can appear colourless, pale yellow or darker. Particle size, concentration, aggregation, light scattering, impurities and storage can all affect their appearance.

Colour is not a reliable quality certificate. Smell and taste cannot establish composition either. Meaningful claims require suitable measurements and transparent information from the manufacturer.

Why a TDS meter is insufficient

A handheld TDS meter usually measures electrical conductivity and converts it to an estimated dissolved-solids reading. It is not selective for silver. Other dissolved ions affect the result, and the meter does not fully characterise silver particles.

A TDS value therefore cannot replace an element-specific silver analysis or a measurement of particle size.

Health and safety context

Historical uses of silver and laboratory findings do not establish a health benefit for a particular bottled dispersion. NCCIH reports a lack of evidence supporting oral health claims and identifies risks including argyria, a usually permanent skin discolouration, and interference with some medicines. Germany’s BfR has also highlighted unresolved safety questions concerning nanosilver in consumer products.

Specific silver-containing medical products, such as certain wound dressings, have their own formulations and intended uses. Their existence is not evidence that a consumer silver liquid is suitable for the same purpose.

This guide does not recommend ingestion, a dose or treatment. Health concerns and possible medicine interactions should be discussed with a qualified healthcare professional.

Questions worth asking about a product

Does “silver content” mean particles, dissolved silver or total silver?
Which method supports the concentration claim?
Are composition, batch and intended use clearly stated?
Are particle characteristics and stability documented?
Are technical findings kept separate from treatment claims?

Key takeaway

Colloidal silver is a dispersion, not a complete specification. Reliable assessment needs more than a PPM number or a photograph: it requires composition, suitable analytical data and a clear intended use.

Frequently asked questions

Is silver water always colloidal silver?

Not necessarily. “Silver water” is not a precise analytical description. A liquid may mainly contain dissolved silver ions, particles or a mixture.

What makes an analysis useful?

It identifies the batch, method and measured quantity. A total silver result does not replace separate information about particle size and the dissolved fraction.