Homeopathic Basic Research: Building on the Past and Imaging the Future

A team of European researchers undertook a three-part study to evaluate existing research entitled, “Physicochemical Investigations of Homeopathic Preparations: A Systematic Review and Bibliometric Analysis.” The stated objective of the work was to “update and expand the current state of knowledge in the area of physicochemical properties of homeopathic preparations.” Study objectives, results, discussion, and conclusions are summarized is this article. Readers are encouraged to read the full research reports for a complete understanding of this work. 

The first part published in 2018 aimed to present an overview of the literature with respect to publication quality and investigation methods used. 183 publications were identified, 122 of which had an MIS ≥5. Techniques most frequently used were electrical impedance (26%), analytical methods (20%), spectroscopy (20%), and nuclear magnetic resonance (19%). 

The second part published in 2019 identified relevant publications of sufficient reporting quality for further in-depth analysis. In this, literature analysis described 203 experiments. Only a small percentage used adequate controls to identify specific effects of homeopathic preparations. 

The third part published in 2021 analyzed these publications to identify any empirical evidence for specific physicochemical properties of homeopathic preparations and to identify most promising experimental techniques for future studies. The focus is on the possible modes of action underpinning homeopathic preparations. A number of effects appear consistently throughout the data: Differences to controls seem to increase with: time, moderate temperature, small samples volume, and in ionic medium, whereas high temperatures seem to abolish differences to controls.

Part 1 

Sabine D. Klein, PhD, Sandra Würtenberger, MSc, Ursula Wolf, MD, Stephan Baumgartner, PhD, and Alexander Tournier, PhD. Physicochemical Investigations of Homeopathic Preparations: A Systematic Review and Bibliometric Analysis—Part 1. Journal of Alternative and Complementary Medicine. Volume 24, Number 5 (2018). Pages 409–421. Mary Ann Liebert Publisher. DOI: 10.1089/acm.2017.0249.

• Objectives: The last systematic review of physicochemical research performed on homeopathic preparations was published in 2003. The aim of the study is to update and expand the current state of knowledge in the area of physicochemical properties of homeopathic preparations. In part 1 of the study, we aim to present an overview of the literature with respect to publication quality and methods used. In part 2, we aim to identify the most interesting experimental techniques. With this, we aim to be in a position to generate meaningful hypotheses regarding a possible mode of action of homeopathic preparation. 

• Methods: A two-step procedure was adopted: (1) an extensive literature search, followed by a bibliometric and quality analysis on the level of publications and (2) a thorough qualitative analysis of the individual physicochemical investigations found. In this publication, we report on step (1). We searched major scientific databases to find publications reporting physicochemical investigations of homeopathy from its origin to the end of 2015. Publications were assessed using a scoring scheme, the Manuscript Information Score (MIS). Information regarding country of origin of the research and experimental techniques used was extracted. 

• Results: We identified 183 publications (compared to 44 in the last review), 122 of which had an MIS ‡5.The rate of publication in the field was ∼2 per year from the 1970s until 2000. Afterward, it increased to over 5.5 publications per year. The quality of publications was seen to increase sharply from 2000 onward, whereas before 2000, only 12 (13%) publications were rated as "high quality" (MIS ≥7.5); 44 (48%) publications were rated as "high quality" from 2000 onward. Countries with most publications were Germany (n = 42, 23%), France (n = 29, 16%), India (n = 27, 15%), and Italy (n = 26, 14%). Techniques most frequently used were electrical impedance (26%), analytical methods (20%), spectroscopy (20%), and nuclear magnetic resonance (19%).

• Conclusions: Physicochemical research into homeopathic preparations is increasing both in terms of quantity and quality of the publications.

Part 2 

Alexander Tournier, PhD, Sabine D. Klein, PhD, Sandra Würtenberger, MSc, Ursula Wolf, MD, and Stephan Baumgartner, PhD. Physicochemical Investigations of Homeopathic Preparations: A Systematic Review and Bibliometric Analysis—Part 2. Journal of Alternative and Complementary Medicine, Volume 25, Number 9 (2019). Pages 890–901. Mary Anne Liebert Publisher. DOI: 10.1089/acm.2019.0064.

• Objectives: In Part 1 of the review of physicochemical research performed on homeopathic preparations the authors identified relevant publications of sufficient reporting quality for further in-depth analysis. In this article, the authors analyze these publications to identify any empirical evidence for specific physicochemical properties of homeopathic preparations and to identify most promising experimental techniques for future studies. 

• Methods: After an update of the literature search up to 2018, the authors analyzed all publications in terms of individual experiments. They extracted information regarding methodological criteria such as blinding, randomization, statistics, controls, sample preparation, and replications, as well as regarding experimental design and measurement methods applied. Scores were developed to identify experimental techniques with most reliable outcomes.

• Results: The publications analyzed described 203 experiments. Less than 25% used blinding and/or randomization, and about one third used adequate controls to identify specific effects of homeopathic preparations. The most promising techniques used so far are nuclear magnetic resonance (NMR) relaxation, optical spectroscopy, and electrical impedance measurements. In these three areas, several sets of replicated high-quality experiments provide evidence for specific physicochemical properties of homeopathic preparations. 

• Conclusions: The authors uncovered a number of promising experimental techniques that warrant replication to assess the reported physicochemical properties of homeopathic preparations compared with controls. They further discuss a range of experimental aspects that highlight the many factors that need to be taken into consideration when performing basic research into homeopathic potentization. For future experiments, the authors generally recommend using succussed (vigorously shaken) controls, or comparing different homeopathic preparations with each other to reliably identify any specific physicochemical properties.

Part 3 

Alexander Tournier, PhD, Sandra Würtenberger, MSc, Sabine D. Klein, PhD, and Stephan Baumgartner, PhD. Physicochemical Investigations of Homeopathic Preparations: A Systematic Review and Bibliometric Analysis—Part 3. Journal of Alternative and Complementary Medicine, Volume: 27, Number 1 (2021). Pages 44–57. Mary Anne Liebert Publisher. DOI: 10.1089/acm.2020.0243.

• Objectives: In parts I and II of our review of physicochemical research performed on homeopathic preparations, we identified relevant publications and analyzed the data in terms of individual experiments, looking for the most promising techniques that were used in the past. In this third part, we analyze the results of the experiments seeking to extract information about the possible modes of action underpinning homeopathic preparations.

• Methods: We summarized the results from the 11 experimental areas previously introduced, extracting the general findings and trends. We also summarized the results in terms of specific research topics: aging, medium used for potentization, sample volume, temperature, material of potentization vessel, and, finally, the use of molecules to probe homeopathic samples. 

• Results: We identified a number of effects that appear consistently throughout the data: Differences to controls seem to increase with: time, moderate temperature, small sample volume, and in ionic medium, whereas high temperatures seem to abolish differences to controls. Based on the present analysis, there is no consistent evidence to date for the nanoparticle hypothesis to explain specific homeopathic treatment effects. However, the quantum coherence domain hypothesis, the dynamic water cluster hypothesis, and the weak quantum theory are still contenders and need to be further assessed experimentally. 

• Conclusions: The field requires further targeted experimentation to validate past findings reporting differences between homeopathic dilutions and controls, and to expand these findings by specifically testing the three main working hypotheses that are currently at hand.

Comments from AAHP 

Hypothesis-generating work can benefit research in the physicochemical and pharmacological properties of homeopathic preparations. Systematic review of methodologies and outcomes can benefit the homeopathic research community by giving direction to the broader research agenda in homeopathy. This systematic analysis of the existing research database establishes a methodological approach that can be applied to both basic and clinical research. 

The approach taken by the authors of this series of papers is a triumph of basic research as well as in applied research. Many criticisms against the homeopathic research database have included poor research methodology and lack of repetition. In this work, the researchers interrogated the database on both points concluding with a way forward. Given the limited resources of the homeopathic research community, focus and methodology hold paramount positions. As we see here, studies published 50 years ago have a role to play in informing the modern research agenda and methodology. With that as a backdrop, only the most rigorous research study designs should be funded.