At a glance: Without suitable analysis, a homemade gold dispersion cannot be reliably assessed for composition, purity or particle distribution. Looking clear or colourful does not establish suitability for ingestion or a medical application.
Why colour is not a quality test
A dispersion's appearance depends on several properties, including particle size, shape, concentration and aggregation. Different materials can produce similar colours. Conversely, a liquid can look unremarkable while containing unwanted dissolved substances or contaminants.
Appearance can be an observation, but it does not identify the complete material or predict how it will behave in the body.
What a PPM estimate leaves out
PPM expresses a proportion and needs a defined basis. It does not by itself give the total gold mass in a container or establish how much is present as particles rather than dissolved species. A calculation based on assumptions is not a substitute for measuring the finished dispersion.
Additional questions include particle-size distribution, surface chemistry, the dissolved fraction, stability and microbiological quality. These properties are relevant even when the nominal gold content appears plausible.
Sources of variation and contamination
Electrodes, vessels and tubing can contribute contaminants. Water composition, salts and organic residues can change the chemistry of production. Particles may grow or aggregate, and the mixture can change during storage.
Electrical equipment and improvised assemblies also carry accident risks. A clean-looking setup does not demonstrate sterile conditions or a reproducible manufacturing process.
Why research preparations are different
Published nanoparticle research typically concerns materials prepared and characterised for a defined experiment. The formulation, coating and measurements are part of the result. Reproducing a colour at home does not reproduce all of those conditions.
Gold's use as the food additive E 175 is not a general endorsement of homemade dispersions. EFSA's 2016 re-evaluation identified insufficient data for a complete risk assessment of that additive; it did not demonstrate health benefits from colloidal gold.
Product category and intended use
A liquid marketed as a cosmetic, food, biocide, medical device or medicine falls under the relevant category's requirements. Classification depends on composition, presentation and intended purpose. Anyone placing a product on the market must assess the applicable rules; describing it as homemade does not remove those obligations.
A private experiment and the marketing of a health product are different questions, and neither establishes clinical effectiveness.
Practical conclusion
Without appropriate measurements, the actual product remains insufficiently known. Homemade production is not a reliable quality strategy for ingestion or medical use. Evaluate characterisation and relevant evidence, rather than relying on colour, a device setting or a PPM estimate.
Frequently asked questions
Does a red or purple colour prove that high-quality colloidal gold has been made?
No. Several particle properties affect colour. It does not establish purity, size distribution or suitability for a particular use.
Is a calculated PPM value an adequate analysis?
No. A calculation based on assumptions does not measure the finished product. Particles, dissolved species, contaminants and stability remain insufficiently characterised.
Related guides
- Colloidal gold in the body: absorption, evidence and risks
- Gold in medicine: pharmaceuticals, nanotechnology and retail colloids
- Colloidal gold and oxidative stress: what research can tell us
Sources and further reading
- EFSA (2016): Re-evaluation of gold as food additive E 175
- Research publication: PubMed 22500239
- European Commission: Borderline products
Editorial update: 4 October 2026. General information; not an individual diagnosis, treatment, ingestion or dosage recommendation.