The pharmaceutical industry in the US recently introduced new self-regulatory guidelines on direct-to-consumer (DTC) advertising, which some suggest are a response to prolonged criticism of its marketing strategies. Current studies conducted by the industry, academics, and regulatory bodies report that consumers find informational value in DTC advertising, yet scant evidence exists as to whether or not consumers actually believe the information presented overall (as opposed to any specific DTC ad.). This paper reports the results of an exploratory investigation into the perceived believability of pharmaceutical performance claims in US DTC advertisements, and whether or not differences exist in the ad.'s perceived believability by source, channel, or message factors, or by consumer demographics. Results are both consistent and, at times, contradictory, to the current level of understanding regarding DTC advertising.