The guidelines say that when ads indicate citation source, scope or validity by
text, images, audio or video, text font, size and color must be clearly legible
to the general public under normal conditions, and audio must match the ad’s
other content in speed, tone and clarity. Where cited advertising includes
product performance, function, use, specifications, shelf life or promotional
terms, advertisers must not use reduced font size, altered typeface or colors
similar to the background—or other means that make these details hard to
discern—to narrow or obscure such information, nor provide explanations or
descriptions that contradict scientific common sense or harm consumers.