Several examples are discussed in this review, where substances without proven effects were proposed for the practical use. The following is discussed here: generalizations of the hormesis concept and its use in support of homeopathy; phytoestrogens and soy products possibly having feminizing effects; glycosaminoglicans for the treatment of osteoarthritis and possibilities of their replacement by diet modifications; flavonoids recommended for the treatment of chronic venous insufficiency and varicose veins; acetylcysteine as a mucolytic agent and its questionable efficiency especially by an oral intake; stem cells and cell therapies. In conclusion, placebo therapies can be beneficial and ethically justifiable but it is not a sufficient reason to publish biased information. Importantly, placebo must be devoid of adverse effects, otherwise it is named pseudo-placebo. Therapeutic methods with unproven effects should be tested in high quality research shielded from the funding bias. Patients participating in such research must be treated free of charge. As for animal experiments, they should be performed by integer researchers not influenced by conflicts of interest. The potential outcomes of some of these issues are not entirely clear, and the arguments provided here can initiate a constructive discussion.
acetylcysteine; hormesis; nutrition; osteoarthritis; phytoestrogens; soybean