Evidence for the effectiveness of homeopathy

The alleged evidence for the effectiveness of homeopathy is insufficient to conclude that homeopathy has any ability to prevent or treat medical conditions in humans or animals &mdash; that is, beyond the baseline factors of the placebo effect and the self-limiting nature of the condition, which is the definition of efficacy in healthcare interventions. In short, the available evidence shows that homeopathy does not work and has no plausible biochemical basis.

The evidence purporting to show a positive effect is of insufficient methodological quality for concluding effectiveness, whilst rigorous trials of homeopathy conducted to high standards have uniformly shown no effectiveness at all. This is the common and expected result of trials into medical interventions that do not work. The burden of proof lies with homeopaths and alternative medicine practitioners to demonstrate its effectiveness; despite this, conventional medicine has put it through its paces with a series of trials and meta-analyses, and the overall scientific consensus is that it does not work. The evidence can be split into two categories: the first looking at the efficacy of homeopathy, and the second looking into the physical claims regarding its supposed method of action, such as water memory or forms of quantum woo.

Medical evidence
There have been several major investigations into homeopathy. The Lancet, one of the world's premier medical journals, has published a few fairly high quality meta-analyses, and the Cochrane Collaboration, practically the place for meta-analyses, has also released a few studies. In general, these studies come out against the effectiveness of homeopathy, although keeping with a scientific view of having an open mind some do conclude "insufficient evidence"; while there isn't enough data to conclusively prove that homeopathy is hokum, there isn't any reliable data pointing towards it having a real and tangible effect. Serious, high quality research has only been recently available.

The Lancet, 1997
A large study from 1997 looked at 186 trials, using 119 of them based on inclusion criteria and determined a small, apparently positive, effect of homeopathy, although nothing conclusive. The paper states: "the results of our meta-analysis are not compatible with the hypothesis that the clinical effects of homoeopathy are completely due to placebo. However, we found insufficient evidence from these studies that homoeopathy is clearly efficacious for any single clinical condition. Further research on homeopathy is warranted provided it is rigorous and systematic." (emphasis added). So while the 1997 survey didn't generate strong evidence to say that homeopathy was bullshit, it didn't offer any proof that it had a genuine clinical effect. The study attracted some criticism that the authors' "prejudice in favour of homoeopathy is obvious". However, Klaus Linde defended the study and welcomed the criticism, recognising the flaws in corrections of publication bias (a complex topic), the fact that inconsistent methods of action for the placebo effect could generate further confusing data, and requesting others to look at the data carefully.

In 1999 Linde and his team published a followup acknowledging that:

The process of science means that it would be misleading and wrong to quote the first finding without noting the second. But who would do such a thing?

Cochrane Collaboration, 1998
The meta-studies performed by the Cochrane Collaboration are regularly updated. Its study on homeopathic treatment of chronic asthma was first published in 1998 and reassessed/updated in 2007. The report looked at various trials of differing quality and "pooled" results, meaning that different remedies were tested, each with a potentially different contribution, and included nearly 600 people. Despite this high risk of bias and false positive results, it found insufficient evidence for a conclusive answer, and certainly no reliably positive effect. The authors concluded that few studies seemed capable of assessing the "package effect", that whereby the non-clinical aspects of the treatment, such as extended consultations and additional woo-ing of patients can contribute greatly to the placebo effect. While such calls for additional or better research are scientifically accurate and honest (although slightly unhelpful) where the data truly is limited, they have drawn criticism from some doctors and researchers, citing that patients are owed more than non-committal statements. This is especially valid given the "extraordinary claims require extraordinary evidence" position taken by skeptics; as homeopathy is an extraordinary claim and "inconclusive" is far from extraordinary evidence.

Cucherat, 2000
The British Homeopathic Association have quoted this from the Cucherat 2000 meta-analysis:

The full quote is:

In fact, one of the study authors specifically said:

TLDR: Your standard quotemine.

The Lancet, 2005
The 2005 meta analysis published in The Lancet examined 110 controlled studies of homeopathy and 110 studies of matched conventional medicine studies. The Lancet study showed that there was no effect beyond that of a placebo for homeopathy. This massive undertaking examined a large amount of evidence and was systematically &mdash; i.e., fairly &mdash; constructed and carried out. The authors concluded that "when account was taken for these biases in the analysis, there was weak evidence for a specific effect of homeopathic remedies, but strong evidence for specific effects of conventional interventions. This finding is compatible with the notion that the clinical effects of homeopathy are placebo effects." (emphasis added) The study was criticised by Klaus Linde (author of the 1997 study above) for its high risk of generating a false-positive when restricting itself to larger studies only and pooling the data, as the efficacy of homeopathy may vary across different treatments. He did, however, agree with the conclusion. Shang ''et. al.'' responded openly to the criticisms by Linde and others and rectified some of the concerns such as the criticism of using 8 larger trials out of 110 to draw conclusions.

Eur. J. Cancer, 2006
In 2006 European Journal of Cancer showed no effect of homeopathy in a meta-analysis of 6 studies.

J. Alt. Med., 2006
Even sympathetic researchers have problems. Homeopathic practitioners published a study performed in Honduras in the Journal of Alternative Medicine that showed homeopathy to have no effect treating diarrhoea.

Positive trials
Some published positive evidence for homeopathy does exist and these papers are often cited repeatedly by practitioners. However, these studies tend to have many methodological flaws and such flaws make the data less reliable. Ineffective blinding (where people may have been aware that they were receiving a placebo rather than treatment) has been known to overestimate the efficacy of a treatment under study by 17%. In addition, ineffective randomisation (where the researchers could choose, consciously or subconsciously, who received the treatment and who received the placebo) can overestimate efficacy by around 30-40%. Taking into account the methods used when analysing data is particularly important if the papers don't mention their methods; i.e., they may have something to hide. When taking into account data from flawed experiments and accounting for the flaws, homeopathy still comes out as no more effective than a placebo.

Homeopathy apologists will also point to the small number of slightly positive results within the higher quality study outcomes, failing to note that it is in the nature of any trial process that the usual confidence interval of p=0.05 means that one in twenty positive results will be false positives. Such apologists prefer to focus on the "problem" of false negatives, which according to them explains the fact that virtually all methodologically sound tests deliver negative results.

Physical evidence

 * See the main article on water memory

Water clusters
One of the key goals for modern homeopaths is to prove the existence of special properties of water or any solvent that allow them to be clinically active despite having no active ingredient in them &mdash; i.e., are just pure solvent. This includes the succussion process that supposedly imparts the memory onto the solvent. These claims aren't entirely beyond medical or scientific testing. As with the medical evidence, this is currently lacking. Some research shows water exists as small, fluxional clusters and dimers in both solution and the gas phase due to its strong propensity for hydrogen bonding. However, these do not explain water memory as they are neither long-lived nor affected by a succussion procedure.

NMR
At least two studies on homepathic solutions by NMR spectroscopy found no difference. This was true of relaxation times, a property of water protons that can be easily measured in a magnetic field. Another study looked at the actual spectrum of water produced by NMR. The conclusion was again negative as despite many new NMR signals appearing in the study, most were identified as artifacts, and the rest as known or unidentified impurities and none were found more frequently or specifically in the homeopathic remedies than in the controls.

Receptor theory
A basic theory underlying molecular medicine and pharmacology is receptor theory which states that active drug molecules dock on certain cell receptors, whereby they induce their specific drug effect through intracellular pathways. As homeopathic drugs are very much diluted (essentially comparable to a grain of salt in the entire ocean) homeopathic drugs are in strong contradiction to this basic theory of molecular medicine and pharmacology. This is why homeopaths argue that hemeopathic drugs work through modification of water molecules in the solution. The physicochemical problems with this hypothesis have been discussed in the above sections.

Overdoses
"The great thing about homeopathy is that you can't overdose on it" &mdash; well, you could fucking drown! One of the key features of any clinically active medication is the ability for it to have an overdose effect. Although this may be very high, or even too high for it to be practically consumable, it is still there &mdash; for instance, vitamin C overdoses, paracetamol overdoses that damage the liver, as well as over-hydration by consuming too much water, which is considered to be one of the reasons why people die after taking ecstasy. In the case of homeopathic remedies, no such observation is made. This is often cited as a good thing by homeopaths as their remedies cannot possibly cause damage; however, this is very much evidence against the remedies having an active clinical effect beyond a placebo (just to reiterate, the placebo workings of homeopathy aren't denied).

The 10:23 Overdose Event was designed to highlight this fact, as 400 homeopathy skeptics simultaneously "overdosed" on store-bought homeopathic remedies. Similarly, James Randi often consumes as many as 100 homeopathic sleeping tablets (a fatal overdose for even the mildest of genuinely active medications) at the beginning of many of his performances and speeches. In a more serious case from late 2009, Alexa Ray Joel, daughter of musician Billy Joel, attempted suicide by consuming Traumeel, a homeopathic remedy for joint pains that is also claimed to act as a sleeping aid. Needless to say, all of these people are alive and well, and it may be the case that Alexa Ray Joel specifically took homeopathic pills so they wouldn't really kill her.