Orthomolecular therapies have been criticized as lacking a sufficient evidence base for clinical use: their scientific foundations are too weak, the studies that have been performed are too few and too open to interpretation, and reported positive findings in observational studies are contradicted by the results of more rigorous clinical trials.[52][57] Accordingly, "there is no evidence that orthomolecular medicine is effective". Proponents of orthomolecular medicine strongly dispute this statement by citing studies demonstrating the effectiveness of treatments involving vitamins, though this ignores the belief that a normal diet will provide adequate nutrients to avoid deficiencies, and that orthomolecular treatments are not actually related to vitamin deficiency.[7] The lack of scientifically rigorous testing of orthomolecular medicine has led to its practices being classed with other forms of alternative medicine and regarded as unscientific.[58][59][60] It has been described as food faddism and quackery, with critics arguing that it is based upon an "exaggerated belief in the effects of nutrition upon health and disease."[11][12][13] Orthomolecular practitioners will often use dubious diagnostic methods to define what substances are "correct"; one example is hair analysis, which produces spurious results when used in this fashion.[7]
