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Committee for the Responsible Use of Silver in Health


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Last updated: 8/20/07


Responsible internal use is entirely safe

Understanding safety considerations

Safe usage with the 12-for-25™ rule and Silver Supplement Safety Chart

Informative manufacturer's safety report

Questionable manufacturers' claims

Responsible internal use is entirely safe

CRUSH intends to bring sanity and factual, responsible information to a field that, until now, has experienced a considerable need for this kind of resource. It seeks to bring reason to the use of silver in health—especially internal use—and to put an end to the irresponsible claims that have existed at both extreme ends. It pulls the plug on the myths that say that any silver product is safe to use in "unlimited" quantity, and it likewise pulls the plug on the nonsense that says that no silver product is safe even if used intelligently and according to directions.

Too much of anything has consequences. Two of the most common conditions for which children are treated at poison control centers are excessive intake of water and excessive intake of salt. In the case of silver, the main consequence of excessive intake is a rare skin discoloration called argyria.

To put things in perspective, however, this only occurs with extremely irresponsible use. As is demonstrated by referring to the U.S. EPA safety guidelines on silver, responsible use of a dietary supplement that contains silver introduces less silver to the body than what could exist in the average person's drinking water intakeless silver than could exist in a liter or two of ordinary drinking water fully meeting EPA guidelines.

Understanding safety considerations

The most definitive and concise government report on the safety of silver is at the following link:

  • Environmental Protection Agency - Integrated Risk Information System - Silver

The Reference Dose (RfD) that it describes is the guideline that all other EPA agencies, including those that set the drinking water standards, refer to as the most authoritative guideline.

In reading the document, note that the RfD that is represented as 5E-3 mg/kg/day should be read as follows:

5 to the exponent of minus 3 (0.001) = 0.005 milligrams per kilogram of body weight per day

Argyria is the condition that the EPA's RfD safety limits for daily intake of silver are based on. Indeed, explanation behind the RfD guideline clearly states, "The critical effect in humans ingesting silver is argyria, a medically benign but permanent bluish-gray discoloration of the skin. Argyria results from the deposition of silver in the dermis and also from silver-induced production of melanin. Although silver has been shown to be uniformly deposited in exposed and unexposed areas, the increased pigmentation becomes more pronounced in areas exposed to sunlight due to photoactivated reduction of the metal. Although the deposition of silver is permanent, it is not associated with any adverse health effects. No pathologic changes or inflammatory reactions have been shown to result from silver deposition." It also clearly states, "Argyria, the critical effect upon which the RfD for silver is based, occurs at levels of exposure much lower than those levels associated with other effects of silver."

Some people have apparently developed the notion that silver is toxic, or that it can build up in certain organs, neither of which is the case or poses any concern at levels below those necessary to cause argyria. Between 1% and 4% of the silver that we ingest is permanently retained in the body, distributed relatively evenly throughout the tissue structure and organs of the entire body. The rest is excreted rather quickly, primarily through the feces.

The question of "parts per million" or "ppm" is often brought up when debating which products are safer than others. Likewise, some manufacturers irresponsibly say that colloidal silver cannot cause argyria, and some irresponsibly claim that silver ions or silver complexes and compounds can be harmful. The fact is that there is currently no reliable scientific data in existence to demonstrate that any form of silver is any more or less likely to contribute towards the manifestation of argyria than any other form. Likewise, there is no scientific data to suggest that silver ions are in any way more or less safe than colloid silver. (As to complexes and compounds, it depends entirely on what the silver is combined with to create the complex or compound. It's like saying water can be unsafe if you mix it with "other" things. If you mix it with fruit juice, it's probably safe. If you mix it with gasoline, it's probably not.) Note that nowhere does the EPA suggest that either of those distinctions has any bearing whatsoever on safe levels of silver ingestion.

What matters is simply knowing and controlling the total level of silver being ingested. Whether or not the form of silver is a factor in how much the silver may play a role in contributing towards argyria, it seems quite clear that if you don't ingest enough silver to exceed safe consumption levels, the form makes no difference and argyria is impossible.

There is no cut-and-dried safe limit of silver ingestion, partly because the RfD is a general guideline and not a cut-and-dried level, partly because individual sensitivity can vary, partly because the time period during which a given quantity of silver is ingested may have a bearing on the safe quantity of total silver ingestion, and partly because it is impossible to determine a safe level of silver ingestion for silver products without first knowing the amount of silver in the food and water intake of the individual.

The fact is that most of us consume a considerable amount of silver in our food and water intake every day, unless we restrict ourselves to purified water that has had most of the mineral content removed. Argyria doesn't "just happen" from ingesting silver. It happens from ingesting far too much silver. The question is, "What is too much silver?"

In answering that, we need to first dispel the myth that ppm has any bearing, other than being used in the math to figure total silver ingestion levels—math which must of necessity factor in the serving or dosing of the product itself.

A bottle of 10-mg tablets of vitamin C and a bottle of 100-mg tablets of vitamin C are each exactly as safe as each other, no more and no less, if the dosing is such that in both cases you're ingesting the identical amount of vitamin C. If you take ten 10-mg tablets or you take only one 100-mg tablet, it's still 100 mg. (The only other difference that matters is comparing prices, for which you would factor in how many capsules of one it takes to equal the same ultimate dosing of the other.) With silver, ppm only matters for knowing how to do the math in order to know how much silver is in a dose in evaluating safety (or for comparing prices).Unlike the milligrams content with capsules, ppm is a bit more difficult to calculate because it's a measurement of silver "concentration," which needs to be factored together with the "quantity" being consumed of the silver product in order to determine the total "amount of silver" being ingested, which is typically represented in milligrams or micrograms (a milligram is equal to 1,000 micrograms).

An important issue to consider is that plain drinking water can contain up to 0.1 mg of silver per liter and be within EPA safety guidelines. If you take a silver supplement that adds a little to that, you're probably fine. If you take a silver supplement that doubles, triples, or quadruples that, you're still "probably" fine, as long as you don't do that every day for many years. The goal is to be taking such small quantities of a silver-containing dietary supplement product that you can take it every day of your entire life and know you're entirely safe, allowing extra room for the many, many days you didn't use a silver-containing dietary supplement. This should be very easy to do and, frankly, should require nothing more that reading and following the label directions of a reputably made and labeled product. Of course, that's assuming you're not taking in an inordinate amount of silver in your daily drinking water or food, or any other source.

In reviewing the math in the EPA IRIS, it's worth noting when considering the RfD that many people must surely be consuming amounts of silver well beyond the RfD in their drinking water all over the country on a regular basis, yet reports of argyria are extremely rare and seem to result almost exclusively from people taking very irresponsible amounts of silver for long periods of time, often taking ounces if not glassfuls per day, and often with homemade products where they can never be sure what the amount of silver is that they're ingesting. Also, we should note, too, that most drinking water is probably well below the RfD, but the silver levels are usually not printed on the labels. Therefore, it's not at all easy to know how much silver one is ingesting from their food and water intake.

Finally, and quite significantly, it's worth noting that the RfD is based on lifelong daily ingestion levels (well, daily use for 70 years). Argyria is generally a matter of total ingested silver over a lifetime, regardless of whether it was ingested in a short period of time or over many years. Although some evidence certainly indicates that the body can only eliminate silver at a certain rate and that, therefore, ingesting considerable quantities over short periods may affect the match, the RfD is generally designed to ensure safe levels of silver assuming ongoing daily intake for life (or 70 years).

Safe usage with the 12-for-25™ rule

The 12-for-25™ rule is a formula devised by Jay Newman, president and CEO of Invision International Health Solutions, manufacturers of a dietary supplement containing silver, and a member of CRUSH.

It provides a simple method for determining how many drops an individual can take per day of any given silver product to be at or below 25% of the RfD guideline.


Note that in the formulas below, the "x" symbol indicates "multiplied by."

The formula is:

12 x pounds ÷ ppm = drops

What that says in plain English is the following:

12, multiplied by the number of pounds of body weight of the person, divided by the ppm of the product, equals the number of drops of the product that it is safe for the person to take per daybecause it will result in an amount of silver intake that is equal to about 25% of the amount of silver the EPA suggests as the safety guideline (RfD) for the upper limit of daily silver intake.

Note: In converting drops to teaspoons and fluid ounces, use the following conversions:

1 teaspoon = approximately 100 drops (actually, about 105 drops)

1 ounce = approximately 600 drops (actually, about 630 drops), or 6 teaspoons

The 12-for-25™ rule can be applied to the ingestion of any product that contains silver, regardless of whether it is commercially produced or made at home and regardless of whether the product is called ionic or colloidal or nano or anything else. (Note that CRUSH strongly advises against homemade silver products unless very diligent steps are taken to determine the ppm of silver in the product being produced. Note, too, that it is not always sufficient to rely on a manufacturer's labeling claims with respect to the ppm of silver in the product. Prudence is advised.)

It maintains that a basic rule of thumb that's probably more than safe is that if your daily intake of silver from a dietary supplement is less than about 25% of the silver that the EPA recommends as safe for daily oral ingestion of silver, you're probably fine. This is like saying that if the EPA's suggested limits on silver concentration in drinking water are exactly met, and a person drinks a liter of water per 77 pounds of body weight, obtaining the equivalent of 25% of that much silver with a dietary supplement will result in about the same amount of silver as their drinking an additional 25% of a liter of their water per 77 pounds of body weight.

All things considered, the 12-for-25™ rule should obviously be a very reliable safety guideline.


To calculate how much that would be, here are some general mathematical guidelines:

The EPA Reference Dose ("RfD"), the recommended safe daily intake limit of silver from all sources, is:

0.005 milligrams ("mg"), which is 5 micrograms ("mcg"), per kilogram (which is about 2.2 pounds) of body weight.

That translates into saying the RfD is about 2.27 mcg per pound of body weight per day.

To target no more than 25% of that, you'd want your silver intake from dietary supplements to consist of no more than 0.5675 mcg of silver per pound of body weight per day.

To calculate that is a bit more tricky.

We'll start by assuming that a drop of water-based ionic silver complex or colloidal silver from a typical dropper contains approximately 0.04683 grams of water* at room temperature based on what we know. (This converts to about 21.3583 drops per gram, and assumes a cc is equal to a gram, which is true to within two-tenths of one percent at room temperature.) Translating that into silver concentration, we have the following:

A drop of a 1-ppm silver product from a dropper contains roughly about 0.04683 mcg of silver.

A drop of a 10-ppm silver product from a dropper contains roughly about 0.4683 mcg of silver.

A drop of a 100-ppm silver product from a dropper contains roughly about 4.683 mcg of silver.

Thus, the silver content of a drop of any given silver product from an eye dropper is roughly about:

ppm x 0.04683

where ppm is the silver concentration, in parts per million, of the given silver product.

(How much silver may be contained in a spray depends on the particular dispenser. A reasonable assumption is that a spray may contain on average the equivalent of roughly about three drops.)

A teaspoon may contain about anywhere from 80 to 100 drops, depending on the reference source you use. For our calculation purposes, we'll call it 100 drops to be conservative (to end up consuming less silver).

With that information, we can now calculate how much it takes to be within 25% of the RfD.

The formula for the calculation to determine how many drops per day is within the 12-for-25™ rule is:

(pounds of body weight x 0.5675) ÷ (ppm v 0.04683)

which can also be represented as:

(pounds of body weight ÷ ppm) · (0.5675 ÷ 0.04683)

or, in a simpler fashion, as:

pounds of body weight ÷ ppm x 12.1183 = safe number of drops per day

or, as:

12.1183 x pounds ÷ ppm = drops

or, rounding it off (to within about 1%) for further simplification, we have the final 12-for-25™ formula of:

12 x pounds ÷ ppm = drops

which is the same as saying:

12 multiplied by pounds of body weight divided by ppm of the product equals the number of drops of the product that can be taken per day that will comprise an amount of silver that's less than 25% of the RfD (EPA recommended safe daily limit of silver from all sources).

For example, say a person weighing 180 pounds has a silver product that has a silver concentration of 20 parts per million, and they want to know how much of the particular product they can take per day that would comprise an amount of silver that's less than 25% of the RfD suggested daily limit of silver from all sources. The math they would perform is as follows:

25% of the RfD for their body weight is "180 pounds multiplied by 0.5675 mcg" which equals 102.15 mcg. That's the total quantity of silver they're going to target as a daily intake limit.

The amount of silver in a drop of their 20-ppm silver is "20 multiplied by 0.04683 mcg" which is 0.9366 mcg.

Then, "102.15 mcg (total silver target) divided by 0.9366 mcg (amount in a drop)" tells them that about 109 drops is how many drops of their 20-ppm product they want to limit themselves to per day since that will comprise an amount of silver that's less than 25% of the RfD.

So, the formula would be:

(180 x 0.5675) ÷ (20 x 0.04683) = 109 drops

The simpler way of reaching the same figure (within about 1%) is using the 12-for-25™ formula:

12 x pounds ÷ ppm = drops

which is:

12 x 180 ÷ 20 = 108 drops

(If we look at the average conversion to teaspoons, roughly one teaspoonful should be a reliably safe amount.)

As a second example, say a 210-pound person has a 100-ppm silver product.

The long form of the math would be:

(210 x 0.5675) ÷ (100 x 0.04683) = 25.45 drops

The simpler way of reaching the same figure (within about 1%), using the "12-for-25™" formula, is:

12 x pounds ÷ ppm = drops

which is:

12 x 210 ÷ 100 = 25.2 drops

The 12-for-25™ rule should keep just about everyone within very safe limits for ongoing daily use of any silver product.

Just remember that the government's RfD is based on a lifetime of consumption, so it stands to reason that most people have plenty of room for making up the difference. It takes a lot of silver to cause argyria. That's why so few people have ever developed it, even with the irresponsible claims made by the manufacturers of some silver products, with the existence of silver in our food and water supply, and with perhaps millions of people having used silver products.

Informative manufacturer's safety report

An excellent report on ensuring safe levels of silver usage is the Silver 100™ Safety Report, published by Invision International, Inc., manufacturers of a dietary supplement containing silver. It puts together some of the most pertinent government reports and regulations related to silver safety. Once you get a feel for the math that's shown in that report, you'll be able to make similar calculations based on the ppm and intended dosing of virtually any silver product you plan on taking. Of course, the 12-for-25™ rule provides a simple calculation to do that for you.

We will be searching for other examples of responsibly researched and presented safety information, and welcome anything you would like to bring to our attention along those lines for our review.

Questionable manufacturers' claims

Unfortunately, we have seen some very irresponsible claims in promotional materials. We suspect that some manufacturers really believe their own claims, while others are not so concerned with facts as with promotion. In either case, the consumer and the entire industry suffer when manufacturers fail to do their homework before making claims, especially when those claims relate directly to product safety.

Questionable claim: colloidal silver can't cause argyria

Some colloidal silver manufacturers claim that because it's colloidal silver, or because it's a certain form of colloidal silver (such as produced using AC/DC current, or pure elemental silver, or any one of a number of descriptions), it cannot lead to argyria—and it is therefore claimed that an individual can safely consume considerable (if not unlimited) quantities of the given product on an ongoing basis without being concerned about argyria. The fact is that there is no scientific data of which we are aware that reasonably supports the conclusion that colloidal silver of any form is less likely to contribute towards argyria than any other form of silver.

Questionable claim: colloidal silver only kills bad bacteria but not good bacteria

The body contains a remarkable quantity of beneficial bacteria, primarily in the gastrointestinal tract, that is vital to a healthy body. In fact, the same form of bacteria can be vitally necessary and beneficial at some times and life threatening at other times, depending on the location in the body and the quantity of the bacteria. Some colloidal silver manufacturers claim that their product, either because it's colloidal silver or for some "special" reasons, only kills the bad bacteria in the body but not the good or beneficial bacteria. We are not aware of any scientific data to reasonably support the position that any silver product is selective in the kind of bacteria that it will or won't kill.

Questionable claims: ppm of homemade colloidal silver products

Equipment and instructions for making homemade colloidal silver products are available in many forms, from buying parts at the local hardware and electronics store to buying ready-to-use equipment. In essentially all cases, the silver concentration or ppm of the resultant mixture will vary, usually very widely, from batch to batch and, in fact, through the production cycle of any one given batch. (Other wide variations in terms of particle sizes and overall composition are typical with homemade products as well.) Regardless of whether a manufacturer claims that a given ppm will result, this should not be taken at face value. Certainly some equipment manufacturer's or providers of do-it-yourself instructions are more knowledgeable and reputable than others, Nonetheless, it is highly advisable to test each batch—by sending a sample out to a lab if necessary—for silver concentration before use, especially when considering long-term, ongoing use of the product.

Questionable claims: taking an amount of silver with the supplement that “equals” the EPA Oral RfD for silver (350 mcg for an average adult) is safe

The manufacturers of some silver supplement products have published so-called "safety" information incorrectly citing the EPA Oral Reference Dose (RfD) for silver in implying that a person can safely take a quantity of their silver product that results in consuming 350 mcg of silver per day. The EPA Oral Reference Dose (RfD) for silver is indeed 350 mcg of silver per day for an “average” (154-pound) adult. However, the RfD is a suggested safety limit for daily oral intake of silver from all sources. In citing the RfD as a guideline for safe usage of a dietary supplement containing silver, it is imperative to address the fact that a substantial portion of the RfD limit is already being used up by the silver in the average individual’s food and drinking water intake, which must be subtracted from the RfD in order to determine what is available for silver from other sources such as a silver supplement. Additionally, the RfD varies based on the individual’s body weight. In order to determine a reasonable usage level for any silver supplement based on the EPA RfD for silver, one must first allow for the silver in the food and water intake as well as make adjustments for the individual’s body weight. (Note that the 12-for-25TM rule does just that.)

Questionable claims: taking silver products by the teaspoon or ounce that contain 2,000-ppm, 3,000-ppm and higher of silver is safe

Some companies sell products they refer to as "colloidal," "ionic" or "nano" silver, which contains silver concentrations as high as 2,000 ppm of silver, 3,000 ppm of silver, and even higher, while suggesting that one should use it by the teaspoonful or even by the ounce per day. This is extraordinarily irresponsible labeling and obviously results in the intake of silver levels far, far in excess of the RfD when one looks at the math. Again, all their claims about their products being "exempt" from contributing towards argyria due to the form of silver or size of the colloidal particles they may claim to have are entirely without any scientific support.


* Note that the exact volume of a drop of liquid will vary, depending on the viscosity of the liquid, shape of the dropper, speed, temperature, and so forth. The figures shown are based on an estimated volume of 0.04683 mcg per drop of the given silver supplement (which is assumed to be water-based).

The 12-for-25™ rule is a trademark of Invision International Health Solutions, Inc.



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