Health Care Professional Information
Common Name
Silver Proteins, Colloidal Silver Proteins, Colloidal Silver Water
Clinical Summary
Colloidal silver consists of silver particles suspended in a liquid. It is often produced by home-made generators. The use of silver medicinals to treat disorders such as epilepsy, gonorrhea, and colds was not uncommon until the mid-20th century. However, silver was replaced by safer therapies in the recent decades. Silver is not an essential mineral and does not serve any physiological function in the body. It denatures proteins by binding to their reactive groups and can inactivate some enzymes by forming hemisilver sulfides with sulfhydryl groups of the enzymes (1). Whereas silver compounds are still used in external preparations as antiseptics, there has been a growing interest in using the colloidal form of silver orally as an alternative medicine. In vitro studies indicate antitumor effects (8), but no human clinical data support the use of oral colloidal silver. However, despite lack of evidence, it is being promoted as a cure for AIDS, cancer, and diabetes.
Silver when taken orally can interact with and reduce the effectiveness of tetracycline, quinolone, and penicillamine. Long term use can cause silver deposition in the skin and mucous membranes leading to an irreversible condition called argyria, characterized by bluish-gray to gray-black pigmentation (7). Other adverse effects include seizures (6) and kidney damage. Pregnant women should not consume colloidal silver as it can cause developmental abnormalities in the fetus (1).
Purported Uses
- AIDS
- Cancer treatment
- Diabetes
- Immunostimulation
- Infections
Constituents
- Silver particles suspended in liquid.
Mechanism of Action
Silver is unstable in suspension form and can bind to proteins. Silver compounds form hemisilver sulfides with sulfhydryl groups that leads to inactivation of enzymes. Silver also has the ability to bind amino, carboxyl, phosphate and imidazole groups (1). Studies have shown that silver accumulates in rat liver and binds with various tissues and basal membranes. It also affects the activities of lactate dehydrogenase and glutathione peroxidase and the peroxidation of membrane lipids (4).
Pharmacokinetics
Approximately 10% of silver salts may be absorbed following ingestion, with increased absorption from ruptured mucus membranes and skin wounds. The half-life varies from several days to months but silver deposited in the skin has a much longer half-life. It is excreted into the bile and eliminated in the feces (1).
Warnings
The Food and Drug Administration (FDA) has issued a consumer advisory about the risk of permanent skin and mucous membrane discoloration known as argyria, associated with use of dietary supplements containing colloidal silver (7).
Contraindications
Pregnant women should not use colloidal silver as it can cause developmental abnormalities in the fetus (1).
Adverse Reactions
- Reported (Oral): Accumulation of silver in the body causes argyria, a bluish-gray discoloration of the skin, which is typically permanent (2) (3) (7) (9) (10) (11) (12).
- Reported (Oral): Myoclonic seizures were reported in a 75-year-old man following self-medication with silver (13).
- Reported (Topical): Topical use of silver nitrate for burns may cause methemoglobinemia.
Exposure to high concentrations of silver, such as in an industrial setting, leads to systemic toxicity (1) (5).
Literature Summary and Critique
Human studies have not been conducted to determine the medicinal effects of colloidal silver. Below are case reports of its toxicity.
McKenna JK, et al Argyria associated with colloidal silver supplementation. Int J Dermatol 2003; 42(7):549.
A 65-year old male developed skin discoloration but had no other symptoms. He had consumed colloidal silver supplements for two years for treatment of diabetes. The discoloration was limited to fingernails but could not be treated by depigmenting creams or chelation. The patient was advised to use sunscreens to prevent further pigmentary changes.
Gulbranson SH, Hud JA, Hansen RC. Argyria following the use of dietary supplements containing colloidal silver protein. Cutis 2000; 66(5):373-374.
A 56-year old man developed bluish discoloration of fingernails (argyria) following consumption of colloidal silver for cold and allergy for 3 years. There was no improvement in the appearance of fingernails 3 months after the patient stopped consuming colloidal silver. He was advised to avoid sun exposure to prevent further discoloration.
Mirsattari SM, et al. Myoclonic status epilepticus following repeated oral ingestion of colloidal silver. Neurology 2004;62:1408-10.
A 71-year old man developed myoclonic status epilepticus and coma following daily ingestion of one ounce of colloidal silver and various herbal remedies for stage B adenocarcinoma of the prostate for a period of 4 months. High levels of silver were found in the plasma, erythrocytes, and cerebrospinal fluid. He remained in a vegetative state and died 5.5 months later despite extensive treatment. Researchers concluded that the neurotoxicity and the resulting death were due to ingestion of colloidal silver.
References
- Fung MC and Bowen DL. Silver products for medical indications: risk-benefit assessment. J Toxicol Clin Toxicol 1996;34(1):119-126.
- Gulbranson SH, et al. Argyria following the use of dietary supplements containing colloidal silver protein. Cutis 2000;66(5):373-374.
- McKenna JK, et al. Argyria associated with colloidal silver supplementation. Int J Dermatol 2003;42(7):549.
- Shinogi M and Maeizumi S. Effect of preinduction of metallothionein on tissue distribution of silver and hepatic lipid peroxidation. Biol Pharm Bull 1993;16(4):372-374.
- Fung MC, et al Colloidal silver proteins marketed as health supplements. JAMA 1995;274(15):1196-1197.
- Mirsattari SM, et al. Myoclonic status epilepticus following repeated oral ingestion of colloidal silver. Neurology 2004;62:1408-10.
- US FDA. Consumer Advisory: Dietary Supplements Containing Silver May Cause Permanent Discoloration of Skin and Mucous Membranes (Argyria). October 6, 2009. http://www.fda.gov/Food/DietarySupplements/Alerts/ucm184087.htm. Accessed November 30, 2009.
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Franco-Molina MA, Mendoza-Gamboa E, Sierra-Rivera CA, et al. Antitumor activity of colloidal silver on MCF-7 human breast cancer cells. J Exp Clin Cancer Res. 2010 Nov 16;29:148.
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Brandt D, Park B, Hoang M, Jacobe HT. Argyria secondary to ingestion of homemade silver solution. J Am Acad Dermatol. 2005 Aug;53(2 Suppl 1):S105-7.
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Chang AL, Khosravi V, Egbert B. A case of argyria after colloidal silver ingestion. J Cutan Pathol. 2006 Dec;33(12):809-11.
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Kim Y, Suh HS, Cha HJ, et al. A case of generalized argyria after ingestion of colloidal silver solution. Am J Ind Med. 2009 Mar;52(3):246-50.
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Chung IS, Lee MY, Shin DH, Jung HR. Three systemic argyria cases after ingestion of colloidal silver solution. Int J Dermatol. 2010 Oct;49(10):1175-7.
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Stepien KM, Morris R, Brown S, Taylor A, Morgan L. Unintentional silver intoxication following self-medication: an unusual case of corticobasal degeneration. Ann Clin Biochem. 2009 Nov;46(Pt 6):520-2.
Consumer Information
How It Works
Bottom Line: Colloidal silver cannot cure cancer, AIDS, or diabetes. Taking too much colloidal silver by mouth can cause skin discoloration, seizures, and kidney damage.
Colloidal silver is a suspension of tiny silver particles in a liquid. Silver compounds are used externally to stop or prevent infections but recently, many people have started taking colloidal silver as an alternative medicine. It is being promoted as a cure for cancer, diabetes, and AIDS although there is no proof it works in humans. Our body does not need silver to function normally. Silver actually denatures proteins and can make many enzymes lose their effects. Long-term oral use of silver can make the skin turn bluish-gray or gray-black in color. It can also cause seizures and kidney damage. Pregnant women should not consume colloidal silver as it has harmful effects on the fetus.
Purported Uses
- Immune system stimulant
No scientific studies support this use. - Diabetes
There are no data to support this use. - AIDS
There is no scientific evidence to support this use. - Cancer
This use is not supported by scientific studies. - Infections
Silver compounds have been used as topical antiseptics but there are no scientific studies to support the oral use of colloidal silver for infection.
Research Evidence
No human studies have been conducted to test the medicinal effects of oral colloidal silver. There are a few case reports on its toxic effects.
A 71-year old man developed seizures and coma following ingestion of one ounce of colloidal silver and various herbal remedies for prostate cancer for 4 months. He remained in a vegetative state and died five and a half months later despite extensive treatment. Researchers concluded that the neurotoxicity and the resulting death was due to ingestion of colloidal silver.
According to another case study, a 65-year old male developed skin discoloration but had no other symptoms. He had consumed colloidal silver supplements for two years for treatment of diabetes. The discoloration was limited to fingernails but could not be treated. The patient was advised to use sunscreens to prevent further pigmentary changes.
A recent case study reported that a 56-year old man developed bluish discoloration of fingernails (argyria) following consumption of colloidal silver for cold and allergy for 3 years. There was no improvement in the appearance of fingernails 3 months after the patient stopped consuming colloidal silver. He was advised to avoid sun exposure to prevent further discoloration.
Patient Warnings
The Food and Drug Administration (FDA) issued a consumer advisory about the risk of argyria, permanent skin and mucous membrane discoloration, associated with use of dietary supplements containing colloidal silver.
Do Not Take If
- You are pregnant (colloidal silver can cause developmental abnormalities in the fetus).
Side Effects
- Reported (Oral): Accumulation of silver in the body causes argyria, a bluish-gray discoloration of the skin, which is typically permanent.
- Reported (Oral): Myoclonic seizures were reported in a 75-year-old man following self-medication with silver.
- Reported (Topical): Topical use of silver nitrate for burns may cause methemoglobinemia.
Exposure to high concentrations of silver, such as in an industrial setting, leads to systemic toxicity.
Last updated: May 16, 2011
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