Colloid

Other Names

Anhydrous Aluminum SilicatesBioelectrical MineralsClay Suspension ProductsColloidal Trace MineralsHumic ShaleMinerales ColoidalesMinéraux ColloïdauxOligo-Éléments ColloïdauxPlant-Derived Liquid Minerals

Synopsis

Colloidal Silver: A Comprehensive Reference

1. Identity, Chemical Nature, and Common Forms

Colloidal silver is defined as a mixture of silver ions and silver nanoparticles suspended in an aqueous medium. Colloidal silver products are made of tiny silver bits that float in a liquid — the same type of precious metal used in jewelry, dental fillings, and silverware. The term "colloidal" in chemistry refers to a heterogeneous mixture in which microscopic particles of one substance are distributed throughout another without settling or dissolving; in this case, silver particles or ions are distributed in water.

Unlike other metals like iron, sodium, or potassium, silver is not an essential mineral and has no known functions or benefits in the human body. The particles in commercial colloidal silver preparations typically range in size, and the physicochemical properties — including particle size, surface charge, and coating — differ substantially across products. Colloidal silver solutions are usually synthesized by electrolysis using a set of silver cathodes.

The term "colloid" in the dietary supplement context also encompasses colloidal minerals — a broader, distinct category of product. Colloidal minerals — tiny, suspended particles of trace minerals in a liquid form — have been marketed for decades as a highly bioavailable way to replenish minerals missing from modern diets. Colloidal minerals are taken from clay or shale deposits. They are trace minerals derived from microscopic sized fossilized minerals, found primarily in Utah and the surrounding areas.

Chemical and Physical Characteristics

Colloidal silver: A mixture of silver ions and silver nanoparticles suspended in an aqueous medium.
Particle size variability: Silver nanoparticles in commercial preparations can be spherical, with particle sizes ranging from 10 to 250 nm.
Colloidal minerals: Some of the minerals found in a colloidal mineral formula include boron, calcium, chromium, copper, iron, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, silver, sodium, sulfur, and zinc.

Common Dosage Forms

Colloidal silver products are often marketed as dietary supplements to take by mouth. These products also come in forms to use on the skin. Colloidal silver may be added to creams, gels, and sprays that are applied to the skin. Colloidal silver products are sometimes sold as homeopathic remedies. Colloidal minerals are most commonly sold as liquid solutions intended for oral consumption.

Commercial colloidal silver preparations vary widely in silver concentration. One commercially characterized product was a colloidal silver solution at a high concentration of 1000 mg/L, stabilized with pectin in distilled water. Other commercially available products have been found containing colloidal silver at concentrations of 15, 30, 55, 80, and 125 mg/L.

2. Traditional and Historical Use

Ancient Civilizations

Metallic silver was known to the Caldeans as early as 4,000 B.C.E., and it was the third metal known to be used by the Ancients, after gold and copper. Over these millennia, silver has been used for numerous medical conditions, mostly empirically before the realization that microbes were the agents of infection.

Silver has been used for at least six millennia to prevent microbial infections. It has been effective against almost all organisms tested and has been used to treat numerous infections and noninfectious conditions, sometimes with striking success.

Colloidal silver's use as a health remedy goes back to 1500 B.C. in China. Ancient civilizations commonly used silver to treat a variety of ailments due to its antimicrobial properties.

Going as far back as the Greek and Roman Empires, there are writings discussing food and wine being stored in silver containers to prevent them from going bad. There are also several records of silver being used to control infections. Hippocrates, the man credited as the father of medicine, taught that silver could help wounds heal and prevent illness.

Medieval Period

During the Middle Ages, while the plague ravaged Europe, many wealthy families had their children suck on silver spoons to help protect against the disease.

19th and Early 20th Century: Medical Use Before Antibiotics

In Europe, 1811 marked a milestone when Carl Crede introduced silver nitrate eye drops for newborns, virtually eliminating gonococcal ophthalmia neonatorum (newborn blindness caused by gonorrhea). Throughout the late 19th century, silver nitrate solutions were also applied to disinfect wounds and ulcerations, earning silver a reputation as a "chemical antiseptic" in an era before modern antibiotics.

Colloidal silver was first used in 1891 by a surgeon named B.C. Crede to sterilize wounds. The use of silver grew in popularity between 1900 and the 1940s, after which antibiotics supplanted the use of silver.

By the early 20th century, before antibiotics dominated, silver formulations like colloidal silver and silver salts treated eye infections, chronic wounds, and mucous membrane conditions. Products such as Protargol and Argyrol addressed gonorrhea and prevented blindness. The 1916 Merck Index listed 18 silver-based medicines, underscoring its status as a pre-antibiotic staple.

During World War I, medics applied silver leaf and salts to battlefield wounds, improving survival rates from otherwise fatal infections.

Colloidal silver (a colloid consisting of silver nanoparticles suspended in liquid) and formulations containing silver salts were used by physicians in the early 20th century, but their use was largely discontinued in the 1940s following the development of modern antibiotics.

Decline and Modern Revival

The fall of colloidal silver was swift after the emergence of sulfa drugs in the 1930s and penicillin in the 1940s. By 1970, colloidal silver had disappeared mainly from medical reference books, and the pharmaceutical industry ceased production.

Since about 1990, there has been a resurgence of the promotion of colloidal silver as a dietary supplement (used internally), marketed with claims of its being an essential mineral supplement, or that it can prevent or treat numerous diseases, such as cancer, diabetes, arthritis, HIV/AIDS, herpes, and tuberculosis.

Traditional Use of Colloidal Minerals

Historically, some Native American tribes used clay as medicine. The medicinal use of clay-based products in modern days was first encouraged by a southern Utah rancher. Native Americans used clay in medicinal clay treatments, the idea being that the minerals were absorbed through the skin.

3. Key Constituents and Established Mechanisms of Action

Active Constituents of Colloidal Silver

Colloidal silver preparations contain two primary active species: silver nanoparticles (AgNPs) and free silver ions (Ag⁺). A great deal of research has been dedicated to providing insight into the mechanism of the antibacterial activity of silver nanoparticle colloidal suspensions and their released silver ionic counterparts. However, there is no consistency in the literature regarding whether the antibacterial effect displayed at the cellular level originates from the AgNPs or their ionic constituents.

Proposed Antimicrobial Mechanisms

The immense antibacterial potential of AgNPs is primarily attributed to the release of silver ions that lead to the disruption of bacterial cell membrane, generation of reactive oxygen species (ROS), inhibition of protein synthesis, and interference with DNA replication.

Four principal bactericidal mechanisms are described in the peer-reviewed literature: bacteriolysis, triggering the destruction or dissolution of cellular membranes; generation of reactive oxygen species (ROS) and free radicals; destabilization of intracellular structures (e.g., mitochondria or ribosomes) and biomolecules (e.g., DNA and proteins); and modulation of signal transduction pathways.

Activity also differs by the size of nanoparticles. If the size of particles is within 10–20 nm, the activity is attributed to the nanoparticles' internalization and interactions with intracellular content. When the size of nanoparticles is more than 20 nm, the action is attributed to silver ions.

The effectiveness of silver ions and AgNPs against gram-positive and gram-negative bacterial cells suggests different modes of action. Gram-negative bacteria were found to be more prone to silver ions, whereas initial evidence suggests that AgNPs display a superior penetration ability into gram-positive bacteria.

Cellular Toxicity Mechanisms

The toxicity of silver nanoparticles in different organs is hypothesized to be due to the same proposed mechanisms of the antimicrobial effects of silver nanoparticles — vigorous oxidation due to ample discharge of silver ions.

Exposure to AgNPs leads to the inhibition of selenoprotein synthesis and inhibition of thioredoxin reductase 1 (TrxR1). These two sites of action are proposed to comprise the likely mechanism underlying increases in oxidative stress, increases in endoplasmic reticulum stress, and reduced cell proliferation during exposure to silver.

Constituents of Colloidal Minerals

There is not enough information to know how colloidal minerals might work. Despite claims that colloidal minerals are more usable by the body than other minerals, there is no evidence to support this idea.

4. Scientific Evidence by Area of Use

4.1 Antimicrobial Activity (In Vitro)

In lab experiments, silver can help kill microbes that cause infections, such as bacteria, fungi, and viruses. AgNPs possess broad-spectrum biocidal potential against bacteria, fungi, viruses, and Mycobacterium, in addition to exhibiting synergistic effects when combined with certain antibiotics.

Silver and most silver compounds have an oligodynamic effect and are toxic for bacteria, algae, and fungi in vitro. This antimicrobial activity in laboratory settings is well established. However, laboratory activity does not translate directly to clinical or therapeutic benefit when taken orally as a dietary supplement.

Evidence strength: The in vitro antimicrobial evidence for silver nanoparticles and silver ions is strong. Translation to oral supplementation efficacy in humans is entirely undemonstrated in controlled clinical trials.

4.2 Topical Wound Healing and Burn Care

The medical uses of silver include its use in wound dressings, creams, and as an antibiotic coating on medical devices. Wound dressings containing silver sulfadiazine or silver nanomaterials may be used to treat external infections.

The FDA approved a number of topical preparations of silver sulfadiazine for treatment of second-degree and third-degree burns. Despite its widespread use, there is only mixed evidence that silver in dressings has any benefit. A 2018 Cochrane review found that silver-containing dressings may increase the probability of healing for venous leg ulcers.

Systemic reviews in 2014, 2017, and 2018 concluded that more modern treatments, both with and without silver, show better results for wound healing and infection-prevention than silver sulfadiazine, and therefore SSD is no longer generally recommended.

Applying colloidal silver to the skin may help treat minor skin infections, but it may not work as well as topical antibiotics.

Evidence strength: Moderate but mixed for topical wound/burn applications using approved pharmaceutical forms (silver sulfadiazine, silver-containing dressings). Evidence does not apply directly to commercial colloidal silver dietary supplement preparations applied to skin.

4.3 Chronic Sinusitis (Topical Nasal Use)

The most rigorously conducted human clinical trial specifically examining colloidal silver for a health condition was a 2017 randomized crossover trial focused on chronic rhinosinusitis. A prospective cohort study was conducted using a convenience sample of 20 randomized patients with crossover methodology, comparing nasal sprays with colloidal silver versus saline. Patients sprayed twice daily for six weeks with the first intervention and then switched to the second for the next six weeks, with measurements made at baseline and each time point. Primary outcomes were changes in SNOT-22 and Lund-Kennedy endoscopic scores.

Results were negative: mean 6-week change in SNOT-22 scores were −2.8 and 1.0 for saline and colloidal silver, respectively (p = 0.373). Similarly, mean 6-week change in Lund-Kennedy scores were −1.4 and −1.1 for saline and colloidal silver, respectively (p = 0.794).

Commercially available colloidal silver nasal spray did not demonstrate any meaningful subjective or objective improvements in patients with recalcitrant chronic rhinosinusitis without polyposis.

Evidence strength: One small (n=20) randomized crossover trial with a null result. The trial itself acknowledged limited power. It is suggested that future studies with a larger number of individuals, as well as the use of different devices for nasal irrigation, should be conducted to reach a definitive conclusion.

4.4 Immune Support and Infection Prevention

Despite being marketed as natural remedies with purported antimicrobial, immune-boosting, and detoxifying properties, these claims are not validated by controlled clinical trials.

No medical evidence supports the effectiveness of colloidal silver for any of the claimed disease indications including cancer, HIV/AIDS, herpes, tuberculosis, and similar serious diseases promoted by supplement marketers.

There is no clinical evidence supporting the use of colloidal silver to prevent or treat COVID-19.

Evidence strength: No credible human evidence for any immune, antiviral, or general infection-preventive benefit from oral colloidal silver consumption.

4.5 Antibiotic Resistance Research (Investigational)

In view of antibiotic resistance in many bacterial strains, the use of colloidal silver is being explored again, especially applying developments in the nanotechnology field, the nanosize being able to change chemical, physical, and optical properties of metals.

Numerous studies have reported that combining antibiotics such as ampicillin, kanamycin, chloramphenicol, enoxacin, neomycin, and tetracycline with silver ions and AgNPs, either conjugated or co-administered, can significantly enhance the antimicrobial activity of both compounds to treat bacteria, even when silver and antibiotics alone exhibited limited antimicrobial activity.

Evidence strength: This research is predominantly preclinical (laboratory and animal studies). It does not constitute evidence that taking commercial oral colloidal silver supplements provides any such benefit, and it should not be conflated with claims made for dietary supplement use.

4.6 Colloidal Minerals: Nutritional Uses

Colloidal minerals are used as a supplement of trace minerals. Colloidal minerals are also used for many other conditions, but there is no good scientific evidence to support any of these uses.

They are promoted for improving blood sugar levels in diabetes, treating arthritis symptoms, reducing blood cell clumping, reversing early cataracts, turning gray hair dark again, flushing poisonous heavy metals from the body, improving general well-being, and reducing aches and pains. None of these claims are supported by clinical trial evidence in the peer-reviewed literature.

Evidence strength: No controlled human clinical trial evidence supports the specific health claims made for colloidal mineral supplements.

5. Body Systems and Health Areas Associated with Colloidal Products

Integumentary system (skin): Argyria (silver deposition and permanent discoloration); wound healing applications for topical/pharmaceutical silver forms; minor skin infections (topical use only, limited evidence).
Immune system: Marketed for immune support; no human clinical evidence for oral use.
Respiratory system: Nasal spray for sinusitis (one null randomized trial).
Renal and nervous systems: Safety concern — potential kidney damage and neurological effects with excessive intake.
Musculoskeletal system (colloidal minerals): Promoted for arthritis and general well-being; no supporting evidence.
Endocrine system: Interaction concern — interference with thyroid hormone (levothyroxine) absorption.
Cardiovascular system (colloidal minerals): Promoted for reducing blood cell clumping; no evidence base.

6. Dosage Forms and Doses Reported in Studies

Commercial colloidal silver products have been found at concentrations ranging from 15, 30, 55, 80, and 125 mg/L, with the oral reference dose established by the United States Environmental Protection Agency (EPA) being 0.005 mg/kg/day.

A comparative theoretical analysis of these commercially available products at those concentrations, based on recommended daily intake and the EPA oral reference dose, indicates a potential toxicological risk due to estimated intake levels that may exceed safety thresholds, particularly in high-concentration products with insufficient labelling or unclear usage guidelines.

In the 2017 clinical trial for chronic rhinosinusitis: a convenience sample of 20 randomized patients used nasal sprays with colloidal silver versus saline; patients sprayed twice daily for six weeks with each intervention. Patients were provided with 20 sealed bottles of pre-filled 120 mL colloidal silver solution in standard nasal irrigation squeeze bottles.

It is not clear how much colloidal silver you can take before it may be harmful. But it can build up in your body's tissues over months or years.

Regarding colloidal mineral supplements: colloidal minerals are used as a supplement of trace minerals, but no standardized dosages have been established in clinical trials, and no dose-response data from controlled human studies are available in the peer-reviewed literature.

In 1999, the U.S. Food and Drug Administration (FDA) ruled that colloidal silver products were not considered safe or effective. There are currently no FDA-approved over-the-counter or prescription drugs containing silver that are taken by mouth.

7. Safety Considerations and Drug Interactions

Argyria

Colloidal silver can cause serious side effects. The most common is argyria, a build-up of silver in the body's tissues causing a bluish-gray discoloration of the skin, which is usually permanent.

Argyria is a rare cutaneous discoloration caused by the intake of silver or various compounds containing silver. One published case involved argyria in a 73-year-old male following ingestion of colloidal silver as an alternative medicine over 5 years, presenting with diffuse, slate-gray discoloration of his face and hands.

The hyperpigmentation of argyria is usually permanent, and it follows a sun-exposed distribution.

Argyria is typically associated with prolonged exposure to silver, including applying silver-containing materials to the skin or body, inhalation in occupational settings, ingestion, and use of colloidal silver and silver-containing medicinals.

Organ Toxicity

Colloidal silver can cause poor absorption of some drugs, such as certain antibiotics and thyroxine (used to treat thyroid deficiency). There is also some evidence that it can cause kidney, liver, or nervous system problems.

In rare cases, too many doses of colloidal silver can cause long-lasting severe health problems, such as kidney damage and seizures.

Drug Interactions

Colloidal silver might decrease how much antibiotic the body absorbs. Taking colloidal silver along with antibiotics might decrease the effectiveness of some antibiotics.

Colloidal silver might decrease how much tetracycline antibiotics the body can absorb. Taking colloidal silver with tetracycline antibiotics might decrease the effectiveness of tetracycline antibiotics. To avoid this interaction, it is recommended to take colloidal silver two hours before or four hours after taking tetracyclines. Tetracyclines include demeclocycline (Declomycin), minocycline (Minocin), and tetracycline (Achromycin).

Colloidal silver might decrease how much levothyroxine the body absorbs. Taking levothyroxine along with colloidal silver might decrease the effectiveness of levothyroxine.

Research shows that silver can inhibit the absorption of antibiotics (tetracycline and quinolone), which decreases their effectiveness.

Colloidal silver may have interactions with medications that can harm the liver (hepatotoxic drugs), as colloidal silver itself might harm the liver.

Reproductive and Developmental Toxicity

Several recent studies have raised concerns regarding the potential reproductive and developmental toxicity of silver nanoparticles (AgNPs). These concerns are especially relevant for dietary supplements containing colloidal silver, which are sometimes used over prolonged periods.

Gut Microbiome Disruption

Exposure to nanomolar levels of Ag ions effectively blocked selenium metabolism, suggesting that Ag ion leaching was likely the mechanism underlying observed changes during silver nanoparticle exposure.

Regulatory Status

The U.S. Food and Drug Administration (FDA) has warned that colloidal silver is not safe or effective for treating any disease or condition. Additionally, the FDA and the Federal Trade Commission have taken action against a number of companies for making misleading claims about colloidal silver products.

Colloidal silver products marketed for medical purposes or promoted for unproven uses are considered "misbranded" under the law without appropriate FDA approval as a new drug. There are currently no FDA-approved over-the-counter or prescription drugs containing silver that are taken by mouth. However, there are still colloidal silver products being sold as homeopathic remedies and dietary supplements.

Contaminant Concerns in Colloidal Mineral Products

Some colloidal mineral products might contain metals such as aluminum, arsenic, lead, barium, nickel, and titanium in potentially harmful amounts.

Summary of Evidence Quality

The overall state of human clinical evidence for orally consumed colloidal silver as a dietary supplement is weak to absent. There is no solid scientific evidence to support any of the health claims made about oral colloidal silver supplements. The antimicrobial activity of silver ions and silver nanoparticles is well documented in vitro, and pharmaceutical forms of silver (silver sulfadiazine, silver-coated wound dressings, silver-alloy catheters) have some clinical backing for topical and device-related uses. However, none of this evidence supports the supplemental, oral use of commercial colloidal silver preparations. No medical evidence supports the effectiveness of colloidal silver for any of the health condition claims made by supplement marketers. For colloidal mineral supplements, there is no good scientific evidence to support any of the uses claimed for these products.

References

Health Conditions

Health conditions that Colloid may help support.

No conditions available.

Body Systems

Body systems that Colloid may help support.

No body systems available.