Homeopathy is a greater than 200-year-old system of medicine, used by nearly 250 thousand physicians and over 500 million people worldwide[1] – making it one of the most popular forms of complementary, alternative and integrative medicine (CAIM). It is based on the concept of ‘treating like with like’ (in Latin similia similibus curentur). Homeopathic medicines appear to stimulate and direct the body’s own self-healing mechanisms, or homeostasis.
Scientific skepticism toward homeopathy frequently arises from its use of highly dilute medicines, but there is a substantial body of research defending it. The methods used to prepare homeopathic medicines are remarkably like cutting-edge nanotechnology and there is growing evidence that nanoparticles play a crucial role in the actions of homeopathic medicines. (Nanoparticles are extremely small particles that range between 1 to 100 nanometers, are only detectable by electron microscopy, and exhibit significantly different physical and chemical properties from their larger material counterparts.)
Data from the federal National Health Interview Survey analyzed by a team at Harvard University show that around 7 million Americans use homeopathy, with steady growth. Users tend to be highly educated females who pursue healthy lifestyles. They use homeopathy for many ailments, but primarily for upper respiratory infections and ear problems, considering it more effective than herbs or nutritional supplements.[2] The demographics of users in France and Germany follows a similar pattern, although use of homeopathy is more widespread in most European countries.[3] A 2022 (October) Marist Poll found that 61% of U.S. households use supplements and other natural and homeopathic medicines daily, while 75% use them at least monthly. The poll also showed overwhelming support for political candidates who support access to these products.[4]
Polypharmacy (the use of multiple drugs), particularly in the elderly is a major challenge to modern physicians. Opiate analgesics (painkillers), psychotropic drugs (including tranquilizers, antidepressants and sleeping tablets) and antibiotics are widely overprescribed and overused, (the overuse of antibiotics has already caused a massive global crisis of antimicrobial resistance, not to mention disturbances in the human microbiome that lead to dysbiosis and chronic inflammatory conditions) and there is strong research evidence suggesting that the adjunctive use of homeopathy in medical practice would reduce the need for many of these hazardous drugs while simultaneously improving clinical outcome.[5],[6]
The research literature offers significant preclinical and clinical evidence in support of the effectiveness of homeopathic medicines in treating individuals with a wide range of common conditions. Homeopathy shows historical, observational, and randomized clinical trial evidence of good outcomes, greater safety, patient acceptance and satisfaction, accessibility, and cost-savings. Homeopathy is often cited as a method “to treat the patient, not the disease,” since it appears to work by strengthening the body’s host defenses and resilience rather than by killing microbes or blocking pathophysiological processes with toxic ingredients.
Comparative effectiveness research examines the results of treatments in real-world situations, as opposed to the artificial conditions often imposed in randomized controlled trials. It compares outcomes in cohorts of patients receiving different treatments. There are several such studies comparing outcomes of patients attending conventional family physicians with family physicians who integrate homeopathy into their practices, including those below.
A study was published in 2020 looking at data from several German statutory health insurance companies offering reimbursement for homeopathic care. In this comparative, prospective, observational study participants in the ICCH (Homeopathy group) were compared with diagnosis, sex, and age matched insured individuals (Conventional group) who received standard medical care without homeopathy. When data from 2,524 participants (1,543 in the homeopathy group) was analyzed the primary effectiveness outcomes (after six months) were statistically significant in favor of homeopathy for migraine or headache, asthma, atopic dermatitis, and depression.[7]
Another study was conducted in Germany that looked at data from more than 15,700 SECURVITA (a German health insurer) insured persons who had been treated with homeopathy for at least three years. In this study, the researchers compared the homeopathy group to an equally large control group that did not receive homeopathic care—only conventional medicines. They found that those receiving homeopathic medicine fared significantly better and needed fewer conventional drugs than those not receiving homeopathic care. This fact was true for children and adults suffering from a very wide array of medical problems.[8]
A multinational comparative effectiveness study led by the American physician David Riley, MD involved 30 doctors, at six clinical sites in four countries, treating patients with acute respiratory illnesses. Response at 14 days was 82.6% favourable for homeopathy compared to 68% for conventional treatment. The rate of adverse reactions to conventional treatment was 22.3%, versus 7.8% for homeopathy. A replication of this study included 1,577 patients, of whom 857 received homeopathic and 720 conventional treatments: improvement was significantly faster when homeopathy was used.[9],[10]
Trichard et al compared a ‘homeopathic strategy’ against an ‘antibiotic strategy’ in routine medical practice in the management of recurrent acute rhino-pharyngitis in 499 children aged 18 months to 4 years old.[11], [12] Family physicians using homeopathy had significantly better outcomes in terms of clinical effectiveness, lower complications, increased parental quality of life, less time lost from work, and reduced cost.
Witt et al. compared homeopathic and conventional family physician’s outcomes in the treatment of chronic conditions commonly encountered in general practice (headache, low back pain, depression, insomnia, and sinusitis in adults; atopic asthma, dermatitis, and rhinitis in children).[13],[14] Nearly 500 patients were treated by 101 homeopathic and 59 conventional family physicians. The patients treated by the two groups of physicians were generally similar, but the “patients who sought homeopathic treatment had better outcomes at similar cost.”
The largest comparative effectiveness study of homeopathy published to date is the EPI3 study. It was a nationwide study in France, coordinated by the Department of Pharmacoepidemiology at the University of Bordeaux. It included 6,379 patients from 804 medical practices comparing treatment outcomes for patients attending conventional, homeopathic, and mixed practice family physicians for musculoskeletal conditions, upper respiratory tract infections, sleep disorders, anxiety, and depression. Patients in the two groups were similar in most respects except that the homeopathic group tended to have more longstanding chronic illness. The authors concluded that patients treated by homeopathic physicians showed a similar clinical progression, used about half the amount of non-steroidal anti-inflammatory drugs (NSAIDs) compared with conventionally-treated patients, had fewer NSAID-related adverse events, and experienced no loss of therapeutic opportunity. [15]
Another study in the EPI3 series yielded an analogous result, showing that patients who consult family physicians certified in homeopathy tended to use significantly less antibiotics and antipyretic/anti-inflammatory drugs for upper respiratory tract infections than those who attended family physicians who prescribe only conventional medications, with similar outcomes. This finding is of considerable public health importance since antimicrobial resistance is now a major global problem, and one of the leading reasons is the overuse of antibiotics for upper respiratory tract infections.[16]
Economic analysis of EPI3 data looked at three types of cost: consultation, prescription, and total costs. Overall health expenditure was 20% less for patients consulting homeopathic family physicians in France compared to conventional family physicians ($78.70 US vs. $98.91 US). The lower cost of medical prescriptions for homeopathic family physicians was partially offset by higher consultation costs. Homeopathic physicians prescribed far fewer potentially hazardous pharmaceutical drugs including psychotropics, antibiotics and non-steroidal anti-inflammatory drugs.[17]
A recent Swiss study analyzed the basic health insurance costs of complementary and conventional medicine, finding that total practice costs for most complimentary and conventional medicine (COM) were similar, but that homeopathy costs were 15.4% less than COM.[18]
In all comparative effectiveness studies of homeopathy, integrating it into health care resulted in better outcomes for patients and improved safety. Those studies that included cost-effectiveness analysis either showed reduced costs or no additional costs.
Physician and consumer confidence in the safety of homeopathy is justified. There is no evidence that homeopathic medicines cause serious or long-lasting harm. A systematic review of the safety of homeopathy, which included a comprehensive search of the English-language literature and enquiries with regulatory authorities, including FDA, concluded: “Homeopathic medicines may provoke adverse effects, but these are generally mild and transient; there continue to be frequent cases of ‘mistaken identity’ where herbal medicines are [erroneously] misclassified as homeopathic, thus artificially raising numbers of adverse events. The main risks associated with homeopathy are indirect, relating to the prescriber rather than the medicine, which can be a problem no matter what modality is used.”[19]
In 2022 Stub et al analyzed 18 studies in a meta-analysis that made an overall comparison between the side effects from homeopathic medicines, conventional medicines, and herbs. “Analysis of sub-groups indicated that, compared to homeopathy, the number of adverse effects was significantly higher for conventional medicine (P = 0.0001), as well as other complementary therapies (P = 0.05).”[20]
Homeopathic medicines are manufactured from botanical, animal and mineral sources. Raw ingredients are serially diluted and vigorously agitated during the homeopathic manufacturing process. Twelve independent research laboratories in the U.S., France, Italy, Russia, and India found that homeopathic medicines contain various nanostructures, including source material, silica, and gas nanobubbles heterogeneously dispersed throughout the colloidal solutions. [21], [22], [23], [24] This work suggests that homeopathic medicines may act like modern engineered nanoparticles, modulating the allostatic stress response network through effects on cytokines, oxidative stress and heat shock protein responses. (Allostasis is the physiologic process of restoring a stable internal environment.)
Investigators from different laboratories demonstrated that homeopathic medicines emit unique electromagnetic and optical signals that distinguish them from placebo control materials.[25], [26], [27], [28], [29], [30], [31], [32], [33], Low doses of nanoparticles appear to initiate the systemic biological adaptive response process known as hormesis. [34],[35] , [36] (Hormesis is the biphasic response pattern seen in all living biologic systems: low doses of a salient stressor agent induce stimulatory effects, while high doses of the same agent induce paradoxically inhibitory and toxic effects. [37], [38]) Further research demonstrates that hormesis effects are also generated in animals exposed to low frequency magnetic fields,[39] suggesting that a more complicated, multiphasic mechanism may be working when homeopathic medicines interact with living systems.
There is a substantial body of research in homeopathy using different animal models, human cells, plants, and other living organisms. Animals were the most often used model system (371), followed by plants (201), human material (92), bacteria and viruses (37), and fungi (32).[40] Of these studies, 89% reported at least one positive result from using homeopathy.
One of the hallmarks of high-quality science involves the capacity to replicate experiments performed by independent researchers. A recent review of biochemical, immunological, botanical, cell biological and zoological experiments using homeopathic dilutions found 98 replicated experiments with over 70% demonstrating positive results.[41], [42]
The mechanisms through which hormesis modulates biological cell defense stress response networks[43],[44], [45], [46] includes changes in patterns of gene activation networks and release of immune system mediators and modulators such as cytokines, reactive oxygen species (ROS), oxidative stress, and heat shock proteins. [47], [48], [49], [50], [51], [52] Many studies indicate that homeopathically prepared materials initiate changes in all these endogenous mediators.
Hormesis initiated by low dose exposures to various agents also augments wound healing,[53] and studies have demonstrated that certain homeopathically prepared medicines mobilize the same processes.[54] Other physiological studies have demonstrated effects on sleeping and waking quantitative electroencephalographic (EEG) patterns in both animals and human subjects[55], [56], [57] suggesting that homeopathic medicines could affect the entire body by producing physical and psychological benefits, which is what has been observed in clinical practice.
There are more than 1,223 published clinical trials of homeopathy in the English language literature alone[58] , including seven systematic review/meta-analyses.[59],[60],[61], [62],[63], [64] Four of these meta-analyses reached the positive conclusion that there is good evidence that homeopathy is clinically effective; two were inconclusive, and one review by Shang et al. 46 found no benefit. The review by Mathie et al.[65] found that the higher the quality of the homeopathic study (i.e., when there was less risk of bias), the greater the likelihood that the study would show positive results.
The single outlier study by Shang et al. based its claims on only eight clinical trials whose identity was withheld until several months after publication, which precluded any informed examination or scientific discourse of the conclusions. The one undisputed conclusion that was achieved by Shang and colleagues was that clinical trials of homeopathy were generally of higher quality than matched trials of conventional medicine: of the 110 clinical trials identified before elimination, 21 trials of homeopathy and only 9 trials of conventional medicine were found to be of high quality.[66],[67]
A leading Swedish medical researcher who reviewed the Shang study noted that: “To conclude that homeopathy lacks clinical effect, more than 90% of the available clinical trials had to be disregarded. Alternatively, flawed statistical methods had to be applied.”[68]
In March 2015, the Australian National Health and Medical Research Council (NHMRC) published an Information Paper titled “Evidence on the effectiveness of homeopathy for treating health conditions.”[69] The paper concluded that “there are no health conditions for which there is reliable evidence that homeopathy is effective.” A Freedom of Information Act request resulted in the revelation that the NHMRC had commissioned an earlier report by a different author, but when the results favored a beneficial role of homeopathy for several health conditions, the report was buried, and its author was fired.
To save face amid claims of gross misconduct, the NHMRC CEO Anne Kelso publicly remarked that, “Contrary to some claims, the [2015] review did not conclude that homeopathy was ineffective.” (sic)
The NHMRC controversy, which remains unresolved to this day, suggests that the stakes against homeopathy may have permeated all levels of society, including academic, scientific, and regulatory communities. This opposition has always been intense, ever since inception, but until recently, the battle had never been waged on clinical or scientific grounds, only on the concepts of implausibility, and the defense of orthodoxy.
Micozzi found that: “Investigations of claims of complementary medicine, all too often, take on the character and tone of ‘debunking’ expeditions rather than scientific experiments… A willingness to report negative findings far exceeds the acceptance of positive findings and there is clear evidence of bias against CAM [complementary and alternative medicine] research.”[70]
Use of homeopathy is geographically widespread and increasing in popularity on both national and international levels. Most independent clinical research and metanalyses demonstrate that homeopathy is superior (looking at both safety and efficacy) when compared with conventional medicine over a wide range of medical conditions. Integrating homeopathy into public health care is associated with many benefits including improved outcome, less use of risky pharmaceutical drugs, including antibiotics and NSAIDs, and significant cost savings,[71] but overcoming deeply entrenched political and scientific bias is an ongoing challenge, but not because of a lack of proven efficacy, safety or benefit.
Iris Bell MD, Ph.D. is Professor Emerita of Family and Community Medicine, Psychiatry, Psychology, Medicine, and Public Health at the University of Arizona College of Medicine. Ronald D. Whitmont, MD, is Clinical Assistant Professor of Family and Community Medicine at New York Medical College. Dr Peter Fisher, MD, also contributed to an earlier version of this piece prior to his death. He was Director of Research and Consultant Physician at the Royal London Hospital for Integrated Medicine (RLHIM) in London, England as well as Physician to HM Queen Elizabeth II. Peter Gold is a senior staff member for the American Institute of Homeopathy.
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