Table 3: Comparison of publications investigating homeopathic preparations with UV, visible and/or near infrared light spectroscopy.

PublicationSubstances tested and controlsMethodsFindings

Ludwig, 1991 [18]Belladonna (30x, 200x), 43% ethanolAbsorbance 190–220 nm
comparison of spectra (no statistical analysis)
Belladonna 30x and 200x showed different UV spectra with a broader peak for 200x.

Zacharias, 1995 [21]2 sets of samples of Lycopodium clavatum (6c, 12c, 100c), 40% water and ethanol mixture (unsuccussed, 3c, 6c)Absorbance 220–800 nm (near zero beyond 400 nm)
comparison of average spectra (5 spectra for each sample; no statistical analysis)
The spectra for each set of Lycopodium and succussed solvent were similar and differed from that of the inert solvent. The 2 sets of succussed Lycopodium samples showed significant differences.
The possible introduction of contaminants during the dynamisation process was suggested.

Zacharias, 1995 [22]3 sets of potentised hydroalcoholic solutions, 2 prepared in pharmacies (3c, 6c), one prepared under rigorous conditions of cleanness (3c, 6c, 9c, 12c)Absorbance 220–800 nm (near zero beyond 400 nm)
comparison of average spectra (5 spectra for each sample; no statistical analysis)
The dynamisation process caused changes in the UV absorption spectra of hydroalcoholic solutions prepared in homeopathic pharmacies, but not between unsuccussed and potentised solutions prepared under more rigorous conditions.
It was concluded that the changes were caused by the introduction of contaminants during preparation of the samples.

Sukul et al., 2001 [20]Nux vomica 30c (succussed and unsuccussed), 90% ethanolAbsorbance 190–500 nm
comparison of spectra (no statistical analysis)
Unsuccussed Nux vomica 30 had its peak at 240 nm with an absorbance of 3.67, succussed Nux vomica 30 had one at 242 nm with an absorbance of 3.66. 90% ethanol had its peak at 206 nm with an absorbance of 2.23.

Korenbaum et al., 2006 [17]7 homoeopathic nosodes (DNA-tox, bacteria, manus, fungus, toxic metal, virus, vanilmandelic acid) and a blank placebo were “imprinted” onto ampoules with saline.Absorbance 600–800 nm
centering of spectra, comparison of electronic-homeopathic copies (EHC) to every of the 3 placebo groups, registration of all wavelengths between 700–800 nm with significant differences, Mann-Whitney- test
The spectra of each placebo group did not essentially differ from those of the other placebo groups.
The spectrum of EHC manus differed significantly from all three placebo groups. The spectra of EHCs DNA-tox and toxic metal differed significantly from two placebo groups. The spectra of EHCs bacteria and vanilmandelic acid differed significantly from only one of the placebo groups. The spectra of EHCs fungus and virus did not differ from any of the placebo groups.

Rao et al., 2007 [19]Nux vomica, Natrum muriaticum (6c, 12c, 30c in 95% ethanol), unsuccussed and succussed ethanolAbsorbance 200–500 nm
comparison of spectra (no statistical analysis)
Natrum muriaticum and Nux vomica had different UV-spectra.
The spectrum of unsuccussed ethanol was significantly different from that of succussed ethanol and the succussed homeopathic remedies, Natrum muriaticum and Nux vomica.

Wolf et al., 2011 [24]SiO2 (10c–30c), S8 (11x–30x), CuSO4 (11c–30c), water succussed but not potentisedTransmission 190–290 nm, 215–290 nm
mean transmission, correction for daily variations, -test, ANOVA
UV transmission of CuSO4 hp (homeopathic preparations) was significantly lower than of controls. The transmission was also lower for both SiO2 and S8, but not significantly. The presence of contaminations was ruled out by inductively coupled plasma mass spectroscopy.
An increase in the solvent’s molecular dynamics for homeopathic preparations was suggested.

Marschollek et al., 2010 [23]S8 (10x–30x), CuSO4 (6c–30c), water succussed but not potentised
Samples were additionally exposed to UV light for 12 h, 37°C for 24 h or 90°C for 15 min.
Transmission 190–340 nm, 220–340 nm
median transmission, correction for daily variations, -test, Levene test
For CuSO4 (but not S8) lower UV transmission and higher variance was found for aged (26–110 days) hp compared to controls.
Incubation of CuSO4 (but not S8) hp at 37°C resulted in significantly lower transmission compared to controls. For each type of exposure, transmission of CuSO4 hp was significantly reduced compared to unexposed hp. For S8, a significant reduction in transmission was observed after incubation at 37°C.

Klein et al., 2012 (present study)S8 (6c–30c), CuSO4 (6c–30c), hypericum (6c–30c), water succussed but not potentised
Samples were additionally exposed to UV light for 12 h, 37°C for 24 h, 90°C and pressure for 20 min or an electromagnetic field for 2 h.
Transmission 190–340 nm, 220–340 nm
median transmission, correction for daily variations, Mann-Whitney- test, Kruskal-Wallis test
Transmissions of controls and hp of S8 differed significantly on two of five measurement days and after exposure to physical factors. Transmissions of hp exposed to UV light and unexposed hp of CuSO4 and hypericum differed significantly. Potency levels 6c to 30c were also compared, and wavelike patterns of higher and lower transmissions were found with significant differences for potency levels of all three substances (as determined by Kruskal-Wallis test).