Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

In 1978, a new approach for the treatment of warts was described, complete with compelling before-and-after pictures. What was it? The application of adhesive tape. This was put to the test head-to-head in a trial of duct tape versus cryotherapy to resounding success.

Now, though this was a randomized controlled study, it wasn’t a double-blind study. “Patients in the duct tape [group] were instructed to remove all tape prior to making a return clinic visit,” so that the nurses measuring the wart changes wouldn’t be biased one way or the other. But remember, the cryotherapy can cause redness, “skin discoloration, crusting” and blisters; so, the nurses may have had an idea which kid was in which group, and maybe that could have biased them. So, ideally, there’d be a double-blind, randomized controlled trial of duct tape for the treatment of common warts, and here we go.

Check it out: this is how they disguised the duct tape so no one knew who was in each group. They used transparent duct tape applied to the underside of moleskin, which is an opaque adhesive pad, and the control group just got the moleskin without the duct tape underneath. So, on the outside, both treatments looked the same, but half the warts were exposed to duct tape, and the other half were not. So, if there was something special about the duct tape adhesive, the duct tape group would triumph, and the straight moleskin group would fail. If there was nothing special about duct tape, and the remarkable success of that other study was just the act of covering warts with anything sticky, then they would both triumph. But instead, they both failed. They both did like no better than placebo.

The “first double-blind controlled trial investigating” duct tape for warts, and it failed “for treating common warts in adults.” Hmm, well maybe that was the problem? The subjects in the original duct tape study were mostly kids—average age nine—whereas in this study the average age was 54. And yeah, warts in younger populations may be more amenable to treatment. So, is it possible the reason duct tape worked in the first study, but not the second, is that duct tape only works in kids, but not adults? Well, you’d have to repeat the same kind of study, but this time with children.

About 100 schoolchildren were randomized to having duct tape applied to the wart, or a corn pad around the wart as a placebo. So, they both did something, but only one group had duct tape on their warts. They used that same clear duct tape, so they wouldn’t recognize it, and it looks nicer too. Six weeks later and—the duct tape failed.

And that’s where the medical community left it. If you look at recent reviews on whether it’s better to burn them, freeze them, or duct tape them, they dismiss duct tape as totally ineffective, which is totally understandable. No matter how good some original results are, if you put the same thing to the test in a bigger, better study and can’t replicate the results, then you have to assume the first study was just a fluke.

But did they put the same thing to the test? Maybe adults weren’t the operative word here, and instead it was…”.transparent.” “Clear duct tape is not duct tape.” It turns out “[c]lear duct tape and moleskin both contain an acrylic-based adhesive, whereas standard silver duct tape contains a totally different rubber-based adhesive.” “It is likely that the success of traditional duct tape is associated with the…adhesive that comes in direct contact with the wart during treatment.” In fact, even more likely after the two clear tape studies came out, showing that indeed it appears to be something unique in duct tape, and not just merely the act of occlusion—just covering a wart up. And indeed, the latest addition to the body of evidence found that similar 80 percent versus 60 percent duct tape over cryotherapy, using real duct tape (but in this case sticking it on with some superglue, so the duct tape would stick better).

In conclusion: “Odd as it may sound, duct tape is a legitimate and often effective treatment for common warts.”

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