The Food and Drug Administration (FDA) does not allow pharmaceutical manufacturers to promote their drugs for indications that the FDA has not approved, but a 2012 federal court case (US v. Caronia) held that this so-called "off-label marketing" could in fact be protected by the First Amendment. The court suggested that the FDA should instead just require that manufacturers add disclaimers to promotional messages that discuss off-label uses. But do disclaimers have any real impact on consumer perceptions about health-related promotional claims? The most common disclaimers in the marketplace currently are found on dietary supplements, warning consumers that the FDA has not approved these products.

Aaron S. Kesselheim of Harvard Medical School and Brigham and Women's Hospital and coauthors conducted a systematic review of studies examining consumers' response to disclaimers on dietary supplements. Nearly all studies found "consumers were generally unaware of the disclaimer or attached no weight to it in their perceptions of the product." Thus, Kesselheim and coauthors concluded, "replacing FDA restrictions...with largely ineffective disclaimers risks returning the pharmaceutical market to a previous era in which such inappropriate marketing claims proliferated, to the likely detriment of the public health."

Research: Mandatory Disclaimers On Dietary Supplements Do Not Reliably Communicate The Intended Issues, Aaron S. Kesselheim, John Connolly, James Rogers and Jerry Avorn, Health Affairs, doi: 10.1377/hlthaff.2014.0515, published March 2015.