Advocates for BHT have claimed that commonly compounded BHT preparations are not commercially available; this is false, as there are many FDA-approved hormone preparations containing bioidentical molecules available both as proprietary or generic brands. The exception is estriol, used in the compounded bioidentical preparations Triest and Biest—in 2008, the FDA banned estriol until a New Drug Application had been completed; these preparations are not approved by either the FDA, or Health Canada. Some advocates of compounding have also falsely claimed that customized compounding provides customized results; this is incorrect since it is aimed at producing a single hormone profile with absolute blood or saliva levels—which has not been demonstrated to be better than CHRT—and does not consider the rate at which individuals will differ in the activity, metabolism and excretion of the hormones. There have been no clinical trials directly comparing the effectiveness or efficacy of bioidentical versus nonbioidentical compounds.