Homeopathy is one of the most popular forms of alternative medicine, especially in Europe and Asia, with perhaps billions of doses of mostly water being given to patients every year. Homeopathy was invented by Samuel Hahnemann in the early 1800's as a response to the brutal and ineffective medical practices of the day, including repeated bloodletting and toxic mixtures administered as remedies. Being a reactionary response to the crude medical practice of the time, homeopathy was conceived under the notion that the underlying nature of disease could never be known, because it involved perturbations of a vital spirit that could not be seen or measured. The role of homeopathy in this conception was to restore a proper balance of vital forces in the body.
Homeopathy is one of the few European medical doctrines of the 19th century that has survived, and even thrived, into the 21st century, despite a lack of supporting scientific evidence. Prior to the application of the scientific method to the study and treatment of human diseases, numerous medical doctrines competed for favor throughout Europe during the Renaissance. These were based on popular concepts of the time, ranging from perturbations of a vital force, to imbalances of good and bad bodily humors. Science was progressing rapidly in Europe in the early 1800's, particularly physics and chemistry, which were much further advanced than biology and medicine. European medical practice was primitive and factionalized, and there was no consensus on disease causation, or treatments.
The basic principle of homeopathy is that any compound that elicits the symptoms of a disease in a healthy person will act to cure the disease in an afflicted person. However, because many of the compounds that were found to elicit disease symptoms were highly toxic, they were diluted extremely before being administered to patients. The degree of dilution became a major focus of homeopaths over the course of the 19th century. Some homeopathic preparations were diluted such that they contained small amounts of botanical or mineral ingredients. Some homeopaths took the dilution process to extremes in an effort to improve their effectiveness. These ultra-diluted remedies were said to be "potentized" by the extensive dilution. Based on mathematical calculations, these potentized remedies are so diluted that they contain virtually none of the starting ingredients. Since the early days of homeopathy homeopaths have claimed that these extremely diluted preparations retain a sort of chemical memory of the previously dissolved compounds, and are more effective than solutions which are less diluted. However, very few scientific studies have been done to determine what solutes are present, if any, in these highly diluted preparations.
Our laboratory began to investigate homeopathic preparations in 2004, and over the course of several years we discovered several interesting facts about these watery concoctions. But before I get to our findings, it may be helpful to go over some of the central claims of homeopaths concerning the nature of their "remedies", how they are prepared, and how they are supposed to work. To simplify things, let's call them homeo preps, because calling them remedies confers on them an attribute that has never been shown.
Homeo preps are different from drugs, antibiotics and other medicinal preparations in several ways, most especially in the method of dilution. Most drugs are highly diluted before they are administered, but homeo preps aren't simply diluted in a single accurate step, they are diluted in many small steps, and their containers are smacked on solid surfaces multiple times between each dilution step. The reasoning behind this strange and stereotypical way of making homeo preps is that the lengthy stepwise dilution and repeated container whacking activities are thought to somehow imprint the water with some medicinal essence of the compounds in the starting solution.
So, for example, to make a so-called "30C arsenicum album" homeo prep, a homeopath would take a pinch of arsenic salt and put it in a glass vial containing water with some alcohol, or a liquor such as brandy. Then the homeopath would cap the glass vial and rap it firmly and repeatedly against a solid surface, like a desk. A small volume of the liquid from the first vial (in this case 1%, hence the "C", which stands for centesimal) is then moved to a new vial containing more water, and the rapping process is repeated. This 100 fold dilution and smacking process is repeated 30 times to make a 30C homeo prep (thirty 100-fold dilutions). According to homeopaths the vial rapping process acts to imprint the water (or brandy) with some medicinal essence of the compounds in the starting solution. Therefore, the more you dilute the solution, and the more you whack it on surfaces, the more of the essence you can impart to the water. However, mathematically speaking, a 100 fold dilution repeated 30 times would exhaust all dissolved compounds after the 12th or 13th dilution step. This means that for a 30C homeo prep to be effective, it would have to retain a medicinal memory of the starting chemicals, because it couldn't contain any of the original molecules.
This notion of imprinting water with molecular signals became so entrenched among homeopaths that they even tried to electronically record "molecular signals" from one solution, and then play them back to a bottle of plain water to see if they could transfer medicinal properties to pure water using radio waves. Needless to say, that didn't work. But this demonstrates how strongly the adherents of homeopathy believe that pure water can be made to have healing powers if you just know how to manipulate it properly.
The other obvious conclusion about homeo preps that comes to mind when you think of diluting a solution until none of the medicinal ingredients are left is that homeopaths have a very unusual concept of dose. In medicine, a pharmaceutical dose is calculated to provide a sufficient amount of the drug in the body to have an effect on some physiological or biochemical target. In homeopathy, the concept of dose is reversed so that less is good, and even less is better, but none is best. This is based on the notion that the imprint of a chemical left in pure water is more effective than an actual low dose of the chemical.
If it is beginning to sound like there is a bit of superstition woven through the process of making homeo preps that may be because homeopaths shun most modern science, and focus narrowly on the idea that water has a memory of what has been dissolved in it. That is where our research into homeo preps began.
In order to use the scientific method to analyze homeo preps, we first decided that it would be a good idea to see if we could devise a bio-assay, or test, that could identify homeo preps and differentiate them from purified water. So we began making homeo preps in our lab according to the standard method of serial dilution and "succussion", which is the homeopathic term for whacking the vials against a solid surface. We made 30C homeo preps in glass vials and then used the resultant solutions to test enzyme activity. What we found surprised us.
When we dissolved two samples of an enzyme, for example acetylcholine esterase, in a homeo prep and in plain water, and then tested enzyme activity levels we found that the enzyme in the homeo prep had about 20% higher activity. This was very surprising because with a 30C homeo prep, we should have had no dissolved compounds remaining in the water. We were intrigued, and these findings prompted us to investigate further. We then repeated the experiment, but the preparations were made in plastic vials instead of glass vials. Under these conditions, no enzyme activity increase was observed.
The conclusion was inescapable, the glass vials were somehow responsible for the enzyme activity enhancing effect. This is important because homeo preps are almost always made in glass vials, rather than plastic ones. We needed to test our home made homeo preps by sensitive analytical methods to determine if any dissolved solids were present. Using several different techniques we quickly found that the homeo preps made in glass vials contained substantial quantities of several elements, whereas those made in plastic vials contained only water. The three most concentrated elements found in the homeo preps made in glass vials were silicon, sodium and boron, with trace amounts of calcium, aluminum and other metals. We then tested off-the-shelf 30C and 200C homeo preps from a local supplier, and they also contained the same glass-derived solutes. It immediately became clear that glass, which is made from silicon dioxide, sodium oxide and boric oxide, was dissolving into the water.
It turns out that the fact that glass leaches compounds into water has been known among glass specialists for a long time. But as biologists who do all of their experiments in plastic vials and dishes, this was information that we normally wouldn't need to know. In contrast, homeopaths prepare their wares in glass vials by repeatedly whacking the vials on a solid surface, so we wondered if this succussion process caused more of the glass compounds to dissolve into the water than simple mixing. Samples were prepared in glass vials and some of them were whacked repeatedly on a solid surface, while others were just mixed by rapidly swirling the vials on a rotary mixer. Lo and behold, the whacked vials contained about 20% more dissolved glass constituents than the swirled vials. Therefore, the major result of the whacking (succussion) process is to put more glass into the water, even though that is not what homeopaths thought they were doing. They thought they were "imparting molecular memories" to the water.
These findings are especially damaging to the claim that the water in homeo preps could retain some type of memory of the compounds that were in the original solution. If the stepwise dilution and vial whacking is supposed to instill the water with a memory of the compounds dissolved in it, then all homeo preps should predominantly retain the memory of dissolved glass. We found the silicon, sodium and boron to be present at concentrations of several milligrams per liter, which would overwhelm any trace amounts of medicinal starting compounds as the solutions were diluted further and further.
Additional experiments demonstrated that the enzyme enhancing effect was due to the silicates leaching from the glass vials, which were interacting with the enzymes, and preventing them from denaturing in water. This was all pretty basic science, and would have been apparent to any homeopath who had actually decided to check what was in the solutions they were making and giving to patients. But science isn't high on the priority list of most homeopaths.