Colloids - safely effective or not?

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This paper is based on published scientific studies. It is crucial to understand that the absence of clinical evidence does not mean that something is ineffective, but merely that insufficient scientifically controlled studies have been conducted or that previous studies have not produced clear results.

All „home“ generators only produce ionized Water - not colloids! Due to the lack of laboratory-certified measuring technology available to laypersons (the often-mentioned conductivity meters do not provide any reproducible and therefore reliable data on the water's ppm (parts per million) again), it is always unknown what „dose“ you are taking. The resulting risks are manifold and should not be underestimated.

The following is scientifically based information for better orientation.

Colloidal silver (Ag)

Current scientific status

Summary of the evidence: For the oral intake of colloidal silver there are No clinical studies, that would demonstrate medical efficacy in the treatment of diseases that meet the standards of evidence-based medicine.

Existing studies and their limitations

In vitro studies (laboratory studies):

Numerous laboratory studies show antimicrobial properties:

• Morones et al. (2005) in Nanotechnology: Silver nanoparticles show antibacterial effect against E. coli at concentrations of 10-100 μg/mL in cell culture
• Rai et al. (2012) in Applied Microbiology and BiotechnologyAntimicrobial activity against multi-resistant bacteria in vitro

Important restriction: In vitro effects cannot be directly transferred to the human organism. The digestive tract, pH value, protein binding and other factors dramatically change the bioavailability.

Animal testing:

• Hadrup & Lam (2014) in Regulatory Toxicology and PharmacologySystematic review - Most animal studies focus on toxicity, not therapeutic effect
• Some animal studies show antimicrobial effects, but dosages and conditions are not transferable to humans

Human studies:

There are No published randomized, placebo-controlled double-blind studies (RCTs), that prove the effectiveness of orally ingested colloidal silver in the treatment of infections or other diseases.

Systematic reviews and meta-analyses

Cochrane Database (2023): No entries for oral intake of colloidal silver for infections

Hadrup et al. (2018) in Regulatory Toxicology and Pharmacology:

• Comprehensive review of silver in medical applications
• Conclusion: Topical application documented, oral application insufficiently researched
• No sufficient evidence for systemic therapeutic effects

The problem of bioavailability

Why oral intake is problematic:

1. Protein binding: Silver ions bind to proteins and chloride ions in the digestive tract
2. Formation of AgCl: Poorly soluble silver chloride is formed in the stomach
3. Low absorption: Only a small percentage reaches the bloodstream
4. Quick elimination: About bile and kidneys

Pharmacokinetic studies:

• Loeschner et al. (2011) in Particle and Fiber Toxicology: Investigation of the distribution of orally ingested silver nanoparticles in rats - low systemic bioavailability
• Van der Zande et al. (2012) in ACS NanoAbsorption of silver nanoparticles <1% of the oral dose

Regulatory position

FDA (USA):

• Classifies colloidal silver as „not safe and effective“ for medical applications
• Ban on medical claims since 1999

EMA (Europe):

• No approved oral silver preparations for systemic infections

BfR (Germany):

• Warning against uncontrolled intake
• No scientific basis for therapeutic claims

Documented risks with oral intake

Argyrie:

• Wadhera & Fung (2005) in American Journal of Clinical Dermatology: Documentation of argyria cases after oral silver ingestion
• Irreversible blue-grey skin discoloration
• Already possible with cumulative doses of 1-5 g silver
• Calculation example: At 10 ppm and 50 mL daily = 0.5 mg/day → critical accumulation possible after 5-10 years

Other documented side effects:

• Neurological symptoms (rare)
• Interaction with medication (antibiotics, thyroxine)
• Possible change in the intestinal flora

Gulbranson et al. (2000) in Journal of ToxicologyCase reports of side effects after long-term oral administration

Colloidal gold (Au)

Scientific status

Medically recognized applications:

Gold compounds (non-colloidal gold) are used therapeutically:

Auranofin and gold sodium thiomalate:

• Approved medication for rheumatoid arthritis
• Finkelstein et al. (1976) in Annals of Internal Medicine: Clinical studies on gold-based antirheumatic drugs
• Important: These are defined chemical compounds, not colloidal suspensions

Colloidal gold - evidence base

Available research:

• Incidental observations: Some historical reports from naturopathy
• In vitro: Gold nanoparticles show anti-inflammatory properties in cell cultures
• Human studies: No published RCTs on orally ingested colloidal gold

Brown et al. (2010) in Nanomedicine: Review on gold nanoparticles in medicine - focus on drug delivery and diagnostics, not on direct therapeutic effect when taken orally

Bioavailability and pharmacokinetics

Absorption:

• Gold nanoparticles are hardly absorbed in the GI tract
• Hillyer & Albrecht (2001) in Journal of Pharmaceutical Sciences<1% oral bioavailability for nanoparticles

No established therapeutic dose for colloidal gold when taken orally

2.4 Security profile

Generally considered safer than silver:

• No risk of accumulation as with silver (no „goldosis“)
• Low toxicity at typical concentrations
• But also no proven effect when taken orally

Colloidal copper (Cu)

Scientific status

Copper as an essential trace element:

Copper is a necessary nutrient (RDA: 0.9 mg/day for adults), but:

• Normal diet covers requirements
• Supplementation only makes sense if there is a proven deficiency
• Turnlund et al. (1998) in American Journal of Clinical Nutrition: Studies on copper homeostasis

Colloidal vs. ionic copper

The problem of differentiation:

• Many „colloidal“ copper products contain primarily ionic copper (Cu²⁺)
• True colloidal particles (Cu⁰) are unstable and oxidize quickly
• No scientific literature on the medical effect of specifically colloidal copper when taken orally

Toxicity risk

Copper has a narrow therapeutic window:

• Overdose: >10 mg/day may lead to toxicity
• Wilson's disease: Genetic disorder with copper accumulation - contraindicated
• Gastrointestinal symptoms: Nausea, vomiting with higher doses

Institute of Medicine (2001)Tolerable Upper Intake Level = 10 mg/day

Colloidal zinc (Zn)

Scientific status

Zinc as an essential trace element:

Well documented importance for the immune system (RDA: 11 mg/day for men, 8 mg/day for women)

Evidence for zinc supplementation (not specifically colloidal)

Colds:

• Hemilä et al. (2017) in Cochrane Database: Meta-analysis of zinc lozenges for colds
  • Result: Reduction in the duration of colds by approx. 33%
  • Important: Studies used zinc acetate or gluconate, not colloidal zinc
  • Dosage: 75-100 mg/day during the common cold

Immune function:

• Prasad (2008) in Journal of Trace Elements in Medicine and Biology: Zinc improves immune response in case of deficiency

Colloidal zinc specific

Lack of evidence:

• No published studies comparing colloidal zinc form with other forms
• No evidence that colloidal zinc has advantages over conventional zinc supplements
• Bioavailability probably similar or worse than established forms (citrate, gluconate)

Risks

Overdose:

• Interference with copper absorption at >50 mg/day long-term
• Gastrointestinal complaints
• Tolerable Upper Limit: 40 mg/day (Institute of Medicine)

Other metallic colloids

Platinum, palladium, other precious metals

Scientific literature:

• Virtually no published human studies on oral administration
• Some in vitro studies on the antioxidant properties of platinum nanoparticles
• No established therapeutic applications when taken orally

Non-metallic colloids

Micellar vitamin preparations:

This is a legitimate pharmaceutical application of colloid technology:

• Goncalves et al. (2021) in NutrientsImproved bioavailability of fat-soluble vitamins through micelles
• Clinically relevant use in malabsorption

Summarized evidence table

colloid	RCT evidence	In vitro activity	Oral bioavailability	Approved medical use oral	Security concerns
Silver	None	High (antimicrobial)	Very low (<1%)	None	High (argyria)
Gold	None	Agent (anti-inflammatory)	Very low (<1%)	None (colloidal form)	Low
copper	None (as colloid)	N/A	Unknown	Only in the event of a proven defect	Medium-high (toxicity)
Zinc	Yes (other forms)	N/A	Probably low	Yes (as salt, not colloid)	Means (in case of overdose)
Platinum/other	None	Weak	Unknown	None	Unknown

Why is there so little clinical research?

Structural reasons

Lack of patentability:

• Natural elements cannot be patented
• No financial incentive for expensive clinical trials (Phase I-III cost 100+ million euros)
• Pharmaceutical companies do not invest without exclusive rights

Regulatory hurdles:

• Unclear classification (dietary supplement vs. drug)
• Standardization problems (variable particle sizes, concentrations)

Methodological challenges:

• Difficult blinding (color!)
• Quality control of the test substance
• Long-term safety studies required

What does this mean for the interpretation?

Absence of evidence ≠ Evidence of absence

The absence of RCTs does not necessarily mean that colloidal metals are ineffective. It means:

1. We have no scientifically robust confirmation of efficacy
2. We cannot provide evidence-based dosage recommendations
3. Long-term safety has not been systematically investigated

Practical concentrations in commercial products

Typical concentrations on the market:

• Colloidal silver: 5-50 ppm (some up to 500 ppm)
• Colloidal gold: 10-30 ppm
• Other metals: 10-50 ppm

Usual dosage information (manufacturer's instructions, not evidence-based):

• 1-3 teaspoons (5-15 mL) daily
• At 10 ppm = 0.05-0.15 mg metal per day

Scientific evaluation of these doses:

• For silver and gold: Probably too low for systemic effect with poor bioavailability
• For essential trace elements (Zn, Cu): Significantly below RDA

Topical vs. oral application - an important difference

Proven topical applications

Silver in wound treatment:

• Vermeulen et al. (2007) in Cochrane Database: Systematic review of silver-containing wound dressings
• Result: Moderate evidence for efficacy in infected wounds
• Mechanism: Direct contact with bacteria, no systemic absorption required

concentrations topically:

• Medical wound dressings: 50-100 ppm silver
• Direct antimicrobial contact

Why does topical work but not oral?

Decisive differences:

1. Direct contact: Silver ions have a direct topical effect on bacteria
2. No GI inactivation: No gastric pH, no protein binding
3. Local concentration: High concentration at the site of action possible
4. Bioavailability irrelevant: Systemic absorption not required

Critical evaluation of anecdotes and field reports

Why personal reports are not enough

Placebo effect:

• For subjective symptoms (fatigue, pain), the placebo response rate is often 30-40%
• Finniss et al. (2010) in Lancet: Review of placebo effects

Spontaneous remission:

• Many illnesses (colds, mild infections) heal spontaneously
• Temporal connection ≠ Causality

Confirmation Bias:

• Tendency to remember and report positive experiences
• Negative experiences are documented less frequently

Publication Bias:

• Positive results are more likely to be published than negative ones
• Many small studies with negative results remain unpublished

What would be necessary for evidence?

Randomized, placebo-controlled, double-blind studies with:

1. Sufficient number of participants (power analysis)
2. Objective endpoints (not just subjective symptoms)
3. Standardized product (defined particle size, concentration)
4. Peer-reviewed publication
5. Replication by independent researchers

Such studies do not currently exist for oral intake of metallic colloids.

Scientific sources for further research

Recommended databases:

• PubMed/MEDLINE: pubmed.ncbi.nlm.nih.gov
  • Search terms: „colloidal silver oral“, „silver nanoparticles ingestion“, „gold nanoparticles oral bioavailability“
• Cochrane Library: cochranelibrary.com
  • Systematic reviews and meta-analyses (gold standard)
• Web of Science: webofscience.com
  • Citation analysis, impact factors

Important review articles:

• Hadrup & Lam (2014): „Oral toxicity of silver ions, silver nanoparticles and colloidal silver - A review“ in Regulatory Toxicology and Pharmacology
• Fung & Bowen (1996): „Silver products for medical indications: risk-benefit assessment“ in Journal of Toxicology
• Lansdown (2006): „Silver in health care: antimicrobial effects and safety in use“ in Biofunctional Textiles and the Skin

Conclusion

Key messages

1. There are no robust clinical studies on the oral intake of metallic colloids (especially silver and gold), that would prove medical efficacy according to the standards of evidence-based medicine.
2. In vitro activity (in the laboratory) is well documented, especially for silver, but Not transferable to oral intake due to extremely low bioavailability.
3. Topical application of silver in wound treatment is Scientifically proven - Here it works through direct contact.
4. Risks associated with long-term oral administration are documented, especially argyria in silver.
5. The lack of evidence is primarily a research problem, This is not necessarily proof of ineffectiveness - there is simply a lack of high-quality studies.

Recommendations from a scientific perspective

If you want to take metallic colloids orally:

• Consult a doctor, especially if you have any existing illnesses
• Be aware that you have a not evidence-based Select treatment
• Monitor possible side effects
• Do not expect a „miracle effect“
• Do not replace evidence-based treatments

For essential trace elements (zinc, copper):

• Conventional preparations are better studied and probably more bioactive
• If you suspect a deficiency, first have a blood level determined

The scientifically honest answer is: We do not know for sure because the necessary studies have never been conducted. The available data suggest that oral bioavailability is too low for systemic therapeutic effects, but definitive evidence in the form of RCTs is lacking.