Friday Favorites: Benefits of Tea Tree Oil for Warts and Cold Sores

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.

“It has been reported that essential oils show not only anti-bacterial and anti-fungal activities, but also antiviral activity.” But, it’s also been reported that “Bigfoot Kept Lumberjack as Love Slave.”

What does the science show? How about pitting essential oils against HSV-1, the herpes virus that causes cold sores?

There’s a drug called acyclovir that helps, but now there are drug-resistant strains. And so, they were looking for other alternatives, and they found that a variety of essential oils at a concentration of just one percent could totally suppress the replication of the virus—including tea tree oil, peppermint, and on down the list. But, this was in a petri dish—what about in people?

Recurrent cold sores affect as many as 20–40 percent. Tea tree oil appeared to work in vitro, so they undertook a randomized, placebo-controlled study “to evaluate the efficacy of topically applied [tea tree oil] in the treatment of [recurrent cold sores].” A 6 percent tea tree oil gel versus placebo gel five times a day and…the average healing time seemed to be a few days shorter, and the virus wiped out a little earlier. But, “none of the differences between groups reached statistical significance”—meaning that small a difference could have just been due to chance. They blamed the sample size, but maybe tea tree oil just didn’t work. 

It would be interesting to put lemongrass oil to the test, since it was the only one still effective at wiping out viral activity at even a 10 times lower dose—0.1 percent—but it doesn’t look like that’s ever been done.

What about warts? Warts are caused by viruses, too. Irish researchers reported a case of successful topical treatment of hand warts in a pediatric patient with tea tree oil. A seven-year-old girl with six warts on the tip of one of her fingers, so heavily clustered as to distort the appearance of her finger, interfering with her writing and piano lessons. She had undergone the standard caustic treatment where you paint them with acid, but they just came back with a vengeance. So, her doctors figured, what the heck, and suggested applying straight tea tree oil. And, after five days, all warts had considerably reduced in size, and in another week, they were all gone. And they didn’t come back.

Not bad compared to conventional wart treatments, which can be really painful; whereas, in this case, the tea tree oil appeared to work with no side effects—only affecting the warts, in contrast to the standard acid treatments, which can damage the surrounding tissue. So, they make an urgent call for randomized, controlled trials, but who’s gonna fund that? It’s like pennies per dose.

But the reason we’d particularly like to see randomized trials for wart treatments is that they tend to get better on their own, disappearing without any treatment typically within a year or two. That’s why “since antiquity it has been believed that warts can be removed by various magical processes.” You pay some witch doctor, your warts go away on their own, and they take the credit. 

Surprisingly, such “charming” of warts was actually put to the test, and… had no effect on the warts. It’s interesting how they do these studies, though. Like this study on whether warts can be prayed away. They used like a placebo prayer, so people didn’t know whether they were in the prayed-for group or not, to exclude the possibility that they mind-over-mattered their own wart cure. That’s been put to the test, too; they used a “magic wand” secretly connected to a circuit such that it tingled when the wand touched the wart, to maximize any placebo effect. And the patients were mostly “unsophisticated Negroes,” wrote these Sixties scientists. Yet, despite their purported “deep belief in magic,” more warts actually disappeared spontaneously in the untreated group compared to the magic-wanded ones, with “no hint of [the mere] suggestion of magical cures being effective.”

I was surprised studies like this were not only performed, but published in decent journals. Evidently, publication followed a considerable debate among the journal editors, but they wanted to “keep an open mind,” they said—”but not so open that [their] brains fall out.”

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• Massing AM, Epstein WL. Natural history of warts. A two-year study. Arch Dermatol. 1963;87:306-10.
• Minami M, Kita M, Nakaya T, Yamamoto T, Kuriyama H, Imanishi J. The inhibitory effect of essential oils on herpes simplex virus type-1 replication in vitro. Microbiol Immunol. 2003;47(9):681-4.
• Carson CF, Ashton L, Dry L, Smith DW, Riley TV. Melaleuca alternifolia (tea tree) oil gel (6%) for the treatment of recurrent herpes labialis. J Antimicrob Chemother. 2001;48(3):450-1.
• Millar BC, Moore JE. Successful topical treatment of hand warts in a paediatric patient with tea tree oil (Melaleuca alternifolia). Complement Ther Clin Pract. 2008;14(4):225-7.
• Hoşrik EM, Cüceloğlu AE, Erpolat S. Therapeutic Effects of Islamic Intercessory Prayer on Warts. J Relig Health. 2017;56(6):2053-2060.
• Clarke GH. THE CHARMING OF WARTS. J Invest Dermatol. 1965;45:15-21.
• Harkness EF, Abbot NC, Ernst E. A randomized trial of distant healing for skin warts. Am J Med. 2000;108(6):448-52.
• Browner WS, Goldman L. Distant healing: an unlikely hypothesis. Am J Med. 2000;108(6):507-8.

Image credit: Jojo via wikimedia.org. Image has been modified.

Motion graphics by Avocado Video