State of Research in Homeopathy and Synthesis of the HRI Report 2024
Summary of the publication "State of HRI Data 2024" from the Homeopathy Research Institute
This article presents a factual synthesis of research data on homeopathy, based on the 2024 report of the Homeopathy Research Institute (HRI)[1]. It should be noted that there is no established scientific consensus on the efficacy of homeopathy and that homeopathic treatments must in no case replace a conventional medical treatment when it is indicated. Nevertheless, a body of research exists and deserves to be examined objectively.
Definition and context
Homeopathy is defined by European legislation as “any medicinal product obtained from products, substances or compositions called homeopathic mother tinctures according to a homeopathic manufacturing process described by the European Pharmacopoeia”[2].
Worldwide, more than 200 million people regularly use homeopathy[3]. Within the European Union, 100 million citizens (29 % of the population) resort to homeopathic medicines[4].
Experimental research
Fundamental research in homeopathy is organized around two main axes: physicochemical research and biological research.
Physicochemical research
Systematic reviews by Tournier et al., covering more than 200 studies, indicate that 72 % of studies reveal measurable and specific physicochemical properties of homeopathic preparations[5]. This research uses cutting‑edge techniques such as Raman spectroscopy, ultraviolet‑visible spectroscopy and nuclear magnetic resonance (NMR).
Several hypotheses are explored regarding potential mechanisms of action, notably the formation of nanostructures during the manufacturing process[6] and the creation of coherence domains during dynamisation[7].
Biological research
In vitro studies
A systematic examination of fundamental biological research indicates that 77 % of the 58 publications studied report measurable effects under controlled conditions[8].
In vivo studies
Systematic reviews by Bonamin et al. (2015) reveal an improvement in methodological quality of animal‑model studies, with 82 % including randomisation and 43 % conducted double‑blind[9].
The work of Endler et al. (2015) on the effect of ultra‑high dilutions of thyroxine in tadpoles was reproduced in seven laboratories across four countries, with a significant alteration of metamorphosis speed (p < 0.001)[10].
Plant‑model studies
The evaluation by Ücker et al. (2018) covering 192 publications shows that 95 % of well‑controlled studies indicate significant effects compared with placebo[11].
Clinical research
Systematic reviews and meta‑analyses
In 2023, a synthesis of 182 randomised clinical trials revealed that 5 meta‑analyses out of 6 demonstrate a significant effect of homeopathy beyond placebo[12].
The meta‑analysis by Mathie et al. (2014) on individualized homeopathy indicates that it would have 1.5 to 2 times higher probability of a beneficial effect than a placebo (OR = 1.53, 95 % CI [1.22‑1.91]), with the most important clinical effects observed in the highest‑quality trials (OR = 1.98, 95 % CI [1.16‑3.38])[13].
Results vary by pathology: positive for fibromyalgia[14], childhood diarrhoea[15] and postoperative ileus[16], but inconclusive for dentistry[17] and psychiatric disorders[18].
It should be noted that the authors themselves qualify these results as preliminary due to the heterogeneous quality of the available evidence. They consistently conclude that further research with more rigorous clinical trials is needed to reach definitive conclusions on the efficacy of homeopathic treatments.
Randomised controlled trials
The current corpus includes[19] :
- 329 clinical studies published in peer‑reviewed journals
- 286 RCTs covering 152 pathologies
- 166 double‑blind RCTs against placebo covering 100 pathologies
Observational studies in real‑world conditions
EPI3 Study (France)
This study of 8 559 patients reports a significant reduction in the consumption of conventional medicines among patients treated by physicians qualified in homeopathy[20][21][22] :
- -57 % of antibiotics for respiratory tract infections
- -71 % of psychotropics for anxiety and depression
- -46 % of NSAIDs for musculoskeletal disorders
These results are associated with equivalent clinical outcomes.
Long‑term German study
A study of 3 677 patients over 24 months reports a sustained improvement of symptoms over 8 years. Severity scores decreased from 6.2 to 2.7 in adults and from 6.1 to 1.7 in children (p < 0.001)[23].
British study
A hospital‑based study followed 6 544 chronic‑disease patients for six years. Among them, 70.7 % reported an improvement in their health status[24].
Economic impact and safety
Economic evaluations
Across 21 analysed studies, 14 report a favorable economic impact[25]. In France, data suggest an average reduction of 35 % of total health expenditures when homeopathy is integrated into care pathways.
The authors conclude that, although the quality of cost‑effectiveness research on homeopathy has improved over time and some high‑quality studies show it can be a cost‑effective option, many poorly conducted studies still hinder any definitive claim. In other words, while some data suggest homeopathy may be cost‑effective, numerous studies remain unreliable, requiring stakeholders to remain cautious in their conclusions.
Safety profile
Meta‑analyses by Stub et al. show adverse‑event rates comparable to placebo (OR : 0.99, 95 % CI 0.86‑1.14) and a rate of serious adverse events lower than 0.0001 %[26][27].
Limitations and perspectives
It is essential to note several important limitations :
- clinical data are scattered, with 286 RCTs covering 152 different pathologies, limiting the ability to draw solid conclusions per pathology.
- the individualisation of homeopathic treatment complicates the design of conventional trials.
- observational studies have inherent methodological limitations (lack of randomisation, selection bias).
- there is no scientific consensus on the mechanisms of action of high dilutions.
Conclusion
This HRI report presents a body of research that, according to its authors, suggests homeopathic treatments could have beneficial effects in certain situations. However, these data must be interpreted cautiously in the absence of scientific consensus.
Homeopathy should never be preferred to a conventional medical treatment when it is indicated. It may be considered as a complementary approach, in consultation with a qualified health professional.
For more information on homeopathy research, visit the website of the Homeopathy Research Institute.
References
[1] Homeopathy Research Institute. State of HRI Data 2024. Available at: www.HRI-Research.org
[2] European Parliament; Council of the European Union. Directive 2001/83/EC of the European Parliament and of the Council of 6 November 2001 on the Community Code Relating to Medicinal Products for Human Use.
[3] Prasad, R. Homoeopathy booming in India. The Lancet, 2007; 370, 1679–1680. DOI: 10.1016/S0140-6736(07)61709-7
[4] Commission of the European Communities. Homeopathic Medicinal Products. (1997).
[5] Tournier, A et al. Physicochemical Investigations of Homeopathic Preparations: A Systematic Review and Bibliometric Analysis—Part 2. J Altern Complement Med, 2019; 25, 890–901. PubMed
[6] Demangeat, JL. Water proton NMR relaxation revisited: Ultrahighly diluted aqueous solutions beyond Avogadro’s limit. Journal of Molecular Liquids, 2022; 360, 119500. DOI: 10.1016/j.molliq.2022.119500
[7] Yinnon, T et al. Domains Formation Mediated by Electromagnetic Fields in Very Dilute Aqueous Solutions. Water, 2015; 7, 48. https://www.worldscientific.com/doi...
[8] Witt, CM et al. The in vitro evidence for an effect of high homeopathic potencies - a systematic review of the literature. Complement Ther Med, 2007; 15, 128–138. PubMed
[9] Bonamin, LV et al. The use of animal models in homeopathic research - a review of 2010-2014 PubMed indexed papers. Homeopathy, 2015; 104, 283–291. PubMed
[10] Endler, PC et al. Amphibians and ultra high diluted thyroxine – further experiments and re-analysis of data. Homeopathy, 2015; 104, 250–256. https://www.sciencedirect.com/scien...
[11] Ücker, A et al. Systematic Review of Plant-Based Homeopathic Basic Research: An Update. Homeopathy, 2018; 107, 115–129. PubMed
[12] Hamre, HJ et al. Efficacy of homoeopathic treatment: systematic review of meta-analyses of randomised placebo-controlled homoeopathy trials for any indication. Syst Rev, 2023; 12(1):191. PubMed | Full text
[13] Mathie, RT et al. Randomised placebo-controlled trials of individualised homeopathic treatment: systematic review and meta-analysis. Syst Rev, 2014; 3, 142. PubMed | Full text
[14] Boehm, K et al. Homeopathy in the treatment of fibromyalgia—A comprehensive literature-review and meta-analysis. Complementary Therapies in Medicine, 2014; 22, 731–742. PubMed
[15] Jacobs, J et al. Homeopathy for childhood diarrhea: combined results and metaanalysis from three randomized, controlled clinical trials. Pediatr Infect Dis J, 2003; 22, 229–234. PubMed
[16] Barnes, J et al. Homeopathy for Postoperative Ileus?: A Meta-analysis. Journal of Clinical Gastroenterology, 1997; 25, 628. PubMed
[17] Raak, C et al. A systematic review and meta-analysis on the use of Hypericum perforatum for pain conditions in dental practice. Homeopathy, 2012; 101, 204–210. PubMed
[18] Rotella, F et al. Homeopathic Remedies in Psychiatric Disorders: A Meta-analysis of Randomized Controlled Trials. J Clin Psychopharmacol, 2020; 40, 269–275. PubMed
[19] Gaertner, K et al. Bibliography of Homeopathic Intervention Studies (HOMIS) in Human Diseases. J Integr Complement Med, 2023; 29, 14–21. PubMed
[20] Grimaldi-Bensouda, L et al. Management of upper respiratory tract infections by different medical practices, including homeopathy, and consumption of antibiotics in primary care: the EPI3 cohort study in France 2007-2008. PLoS One, 2014; 9, e89990. PubMed | Full text
[21] Grimaldi-Bensouda, L et al. Homeopathic medical practice for anxiety and depression in primary care: the EPI3 cohort study. BMC Complement Altern Med, 2016; 16, 125. PubMed
[22] Rossignol, M et al. Impact of physician preferences for homeopathic or conventional medicines on patients with musculoskeletal disorders: results from the EPI3-MSD cohort. Pharmacoepidemiol Drug Saf, 2012; 21, 1093–1101. PubMed
[23] Witt, CM et al. How healthy are chronically ill patients after eight years of homeopathic treatment?—Results from a long term observational study. BMC Public Health, 2008; 8, 413. PubMed
[24] Spence, DS et al. Homeopathic treatment for chronic disease: a 6-year, university-hospital outpatient observational study. J Altern Complement Med, 2005; 11, 793–798. PubMed
[25] Ostermann, T et al. Overview and quality assessment of health economic evaluations for homeopathic therapy: an updated systematic review. Expert Review of Pharmacoeconomics & Outcomes Research, 2024; 24, 117–142. PubMed
[26] Stub, T et al. Adverse effects of homeopathy, what do we know? A systematic review and meta-analysis of randomized controlled trials. Complement Ther Med, 2016; 26, 146–163. PubMed
[27] Stub, T et al. Adverse effects in homeopathy. A systematic review and meta-analysis of observational studies. Explore, 2022; 18, 114–128. PubMed
Article written from the report "State of HRI Data 2024" of the Homeopathy Research Institute.