On the other hand, silver undoubtedly has antimicrobial properties, along with some other metals such as copper. Historically, coins or other items made of silver were used to help keep water from becoming contaminated and to keep milk fresh for longer periods when refrigeration was not available. This method may still be used today in some remote areas of the world. Silver is also impregnated into some water filtration systems used both for swimming pools and for drinking water.
Despite the proven antibacterial, antiviral, and anti-fungal properties of silver in vitro, it is unclear whether it can exert the same effects when taken into the body. Part of the issue is what concentration of silver reaches the area where the infection is occurring before being bound, disseminated, or excreted. Another question is whether the ingested silver would have an adequate time of contact with the target organisms to produce the desired effect. It has a greater chance of benefiting a patient with local and topical infections.
Colloidal silver products are often touted as the answer to the problem of microbial resistance to antibiotics. While it is certainly true that antibiotics are overused, leading to more bacteria becoming resistant, substantive evidence that colloidal silver is a safe and effective replacement does not yet exist.
Silver is already used in some compounds that are in common use against infections. Silvadine is a frequently used agent to prevent infection in burn patients. Silver nitrate was used in the eyes of newborns for years to prevent blindness caused by contracting gonorrhea, a sexually transmitted disease (STD), during the passage through the birth canal. The medication was not, however, effective against chlamydia, another STD that causes neonatal conjunctivitis. Silver nitrate can also be very irritating to the tissues of the eye. Erythromycin and tetracycline are now more frequently used in the United States for neonatal prophylaxis.
The claims made for colloidal silver are innumerable. Silver has been said to be effective against hundreds of strains of bacteria, and to be supportive in the treatment of colds and flu, hepatitis, Epstein-Barr virus, pneumonia, bronchitis, and yeast infections. It has also been recommended for topical use in the mouth, eyes, ears, nose, sinuses, and for a wide variety of skin conditions. It is difficult to determine which of the claims, if any of them, have merit because substantive research data are lacking. Most of the reported effects are based on in vitro or anecdotal evidence. Extrapolations from such testimonials would be challenging due to the variability in particle size, concentration, quality of the preparation, and total dose.
Silver colloid has been created by grinding, wave method (such as ultrasonic), liquid, chemical, or electrical modes of manufacture. They vary in how large the particles of silver are that are produced, and whether they carry an electrical charge. Particles that are very small and charged repel each other enough that they tend to remain in a suspended state for a longer time rather than settling. Currently, the electrocolloidal process is the most used, and considered to be the best at creating very small, charged particles.
Colloidal silver may be purchased ready for use, but products have been found to be inconsistent in content, varying from 15–120% of the silver concentration they are labeled to contain. Commercially produced products vary greatly in particle size, potency, stability, and contents. Some contain stabilizers or trace elements in addition to silver, which are considered undesirable. Others have been found to have bacterial contaminants.
The Food and Drug Administration (FDA) at one time considered it a medication, exempted from the standard regulations as a result of being used and marketed prior to 1938. Since that time, the exemption has been revoked. In the United States, silver is now considered a dietary supplement as opposed to an over-the-counter medication. As such, specific claims to benefit or treat medical conditions can not be made.
As an alternative to manufactured colloidal silver products, assorted kits are available for the individual to make colloidal silver for personal use. These kits generally use an electrical current to disperse particulate silver into the carrier. Important factors for producing colloidal silver at home are the purity of the silver, the purity of the water, and proper timing to form the desired concentration. Stability of the colloid is variable, and the silver will tend to gradually settle as the charge on the particles dissipates.
The deposition of silver under the skin can cause a condition called argyria. This condition is not common, but the skin of those who are affected is permanently stained a blue or gray color. The type of silver compound, length of treatment, concentration, and total dose required to cause argyria is a matter of some debate. There seems to be a great individual variation in susceptibility. Proponents claim that the true colloidal form of silver cannot cause the condition, but for safety purposes, all silver consumed should be considered a potential contributor to argyria. Some colloidal silver products include this warning on the label.
Extremely large doses of silver, much beyond what is recommended by proponents for therapeutic use, may cause neurologic signs or organ damage. Most of the studies of toxicity have been performed using salts of silver, such as silver nitrate, which have a higher silver concentration and greater toxicity than colloidal forms. The latter are generally in the range of 5–10 parts per million (PPM), which is equal to a 0.0005–0.001% solution.
There are no reported side effects.
Interaction of colloidal silver with foods, medications, or herbs are not documented.
Baranowski, Zane. Colloidal Silver: The Natural Antibiotic Alternative. New York: Healing Wisdom Publications, 1995.
Barrett, Stephen. Colloidal Silver: Risk Without Benefit. http://www.quackwatch.com/01QuackeryRelatedTopics/PhonyAds/silverad.html. 1999.
Hill, John. A Brief History of Silver and Silver Colloids in Medicine. http://www.clspress.com/history.html. 1998.
Weil, Andrew. Charmed by Colloidal Minerals? http://www.pathfinder.com/drweil/qa_answer/0,3189,252,00.html. 1997.
Weil, Andrew. Colloidal Silver: Better than Antibiotics? http://www.pathfinder.com/drweil/qa_answer/0,3189,1665,00.html. 1999.