Is Using Toothpaste on Cold Sores All it’s Cracked Up to be?

A forum reader wrote:

“has anyone used toothpaste to help prevent and treat cold sores? I’ve gotten cold sores my whole life and i’m always on a constant quest to find what helps to prevent and shorten the duration of cold sores. I use paste instead of gel and i put it on my lip when i start to feel the tingle. it also helps to dry up the cold sore. you want to keep it on your lip for hours like over night. the only draw back is that sometimes it’ll cause my lips to get chapped.”

Now, I’ll come clean right off the bat and say that toothpaste is one of the few cold sore treatments I have never tried.

Why? Guess I had just never heard of it when I would have needed it. I always just assumed toothpaste was only good for keeping my pearly whites pearly white.

Still, it amazes me how people will try just about anything they have lying around their house on their cold sores.

I mean, if you get cold sores on a regular basis, don’t you always have a tube of actual cold sore cream laying around just in case?

I for one ALWAYS had (and have) some kind of cold sore cream on hand, what with the brutal outbreaks that would hit me left and right practically every month way back when. Always ready to fight.

But hey. A good number of people online are saying that covering their cold sore in toothpaste has worked wonders for them. Who knows. Maybe it could have saved me a lot of pain and embarrassment.

Then again, lots of other people say toothpaste has done nothing for them. So maybe toothpaste would NOT have saved me a lot of pain and embarrassment.

So how about we find out what the heck is going on.

What are the ingredients contained in toothpaste that may or may not help fight off cold sores?

The first thing we need to figure out is just what ingredients in that tube of colgate have the potential to fight off cold sores or the herpes virus.

As it turns out, there are quite a few ingredients in toothpaste, a lot of which are slightly difficult to pronounce.

Most “normal” toothpastes contain a combination of sodium lauryl sulfate (SLS), fluoride, triclosan, propylene glycol, diethanolamine (DEA), hydrogen peroxide and/or dioctyl sodium sulfosuccinate. Of course, some of the fancy schmancy ones can contain other stuff, but by and large these are the ingredients that make up toothpaste.

Quite the laundry list, I know…

The good news is most of the cold sore fighting power of toothpaste is attributed to sodium lauryl sulfate (according to the info I could find online anyway).

What the heck is sodium lauryl sulfate and how does it help with cold sores (if at all)?

I’ll admit, I had no idea what the hell SLS was when I first read about it. But that’s what google’s for, right?

Turns out sodium lauryl sulfate (also known as sodium dodecyl sulfate) is a surfactant used in many cleaning and household products. Stuff like laundry detergent, floor cleaners, soap, bubble bath, toothpaste (duh), etc.

What’s a surfactant you ask? It’s a compound that lowers the surface tension between two liquids…

That’s the boring sciencey answer.

In plain ol’ English, It basically means that SLS acts as a detergent/foaming agent.

In the context of soap and/or toothpaste, it means it helps dissolve oils and makes the water all bubbly and foamy and makes you look like you have rabies when you brush your teeth.

But the question here is, what can sodium lauryl sulfate do against cold sores and/or the herpes virus?

Well, it turns out that SLS also has potent protein denaturing properties, i.e. it can “break-down” proteins so that they can’t be used for whatever they are needed for.

In the case of the herpes virus, if you were to treat it with SLS, it would essentially destroy the viral particles by breaking down the proteins holding them together, thus making them unable to infect anything.

And in fact, one study from 2002 in the journal Antimicrobial Agents and Chemotherapy found that cell cultures treated with SLS both inactivated the herpes virus and reduced their ability to infect healthy cells.

However, this study also found that SLS was much more effective at preventing cell infection when the herpes virus was pre-treated with SLS (i.e. the herpes virus was inactivated with SLS before being tossed to the healthy cells).

What this study tells us is that SLS is pretty effective at destroying the herpes virus, especially if you can catch it before cells are infected. But once cells are already infected the effects of SLS drops quite a bit (the bad news: when you get that tingling feeling on your lip, your skin cells are already infected).

But that doesn’t mean SLS is useless.

See, the herpes virus works by high-jacking a healthy cell to make copies of itself that can then go off and infect other healthy cells. That’s how it spreads. And the moment when it jumps from cell to cell is when SLS would be most effective (theoretically).

Of course, the bigger question is just how effective is SLS against the herpes virus compared to a more common cold sore treatment like acyclovir. Unfortunately, that is something science has yet to investigate, as far as I can tell.

All we have to go on regarding the actual efficacy of SLS is anecdotal evidence, which is pretty evenly split between “the-best-thing-since-sliced-bread” and “this-made-my-cold-sore-10-times-worse-overnight”.

Does sodium lauryl sulfate cause side effects?

During my research, I came across some pretty big claims regarding some pretty nasty side effects caused by SLS.

Heck, some people would have you believe sodium lauryl sulfate is the devil incarnate.

In fact, there are entire websites dedicated to “living an SLS free lifestyle” that explore the negative health and environmental consequences of using it in everyday household products like soap, shampoo, toothpaste, etc.

Some even claim super nasty side effects like cancer.

Now I don’t know about you, but the last thing I want when I’m treating a cold sore is to end up even worse off. So if there are nasty side effects, I want to know. Because hey, beyond perhaps using it as a simple cold sore treatment (if the occasion arises), I actually brush my teeth every day with the stuff.

Thankfully, it seems that claims like these are nothing more than fear mongering, since most scary claims regarding SLS have no leg to stand on.

Case in point, a quick search into the scientific literature yields this article (among others), which reviews and debunks many of the doomsday claims made regarding SLS.

In fact, it states that SLS is only toxic if swallowed in massive quantities. In fact, you’d probably have to chug down a full glass of 100 percent pure SLS to be in any real danger (obviously, don’t try it at home, or anywhere else for that matter).

And given that sodium lauryl sulfate is only found in very small concentrations in toothpaste (usually weighing in at around a whopping 2 percent), you’d have to swallow a butt-load of toothpaste if you were to try and end yourself instead of your cold sore.

Plus, there is absolutely no scientific evidence that links SLS to cancer. None.

The worst potential side effect of side effect of SLS I could find is that it can sometimes cause canker sores in some people (which aren’t cold sores).

But for most people? It may cause mild irritation. As in getting shampoo in your eye. Very annoying, yes, but pretty harmless.

So yeah, I’d say that the amounts of SLS found in toothpaste is pretty damn safe and that if you were to try and use it on your cold sore, your biggest problem is gonna be the stinging sensation of minty freshness.

It’s true, some people have reported that using toothpaste on their cold sore has made it a whole lot worse in a matter of hours, but in my opinion that is more of a failure of SLS having any substantial effect on reducing the viral load and not because sodium lauryl sulfate actively makes cold sores worse (because it doesn’t).

What about the other ingredients contained in toothpaste, any cold sore fighting power there?

Of course, SLS doesn’t bunk alone in your toothpaste tube. So what about the other ingredients in toothpaste? Any of them have cold sore fighting superpowers?

Let’s take a gander at some of the most common ingredients.

Fluoride: Toothpaste usually contains fluoride in the form of sodium fluoride. It’s used to prevent tooth decay. Unfortunately, there’s no evidence supporting its effectiveness against viral infections. Worse, it’s sometimes used in scientific studies to induce high levels of oxidative stress (and we all know how bad stress is for cold sores…). Of course, I wouldn’t worry about the small amount of sodium fluoride contained in toothpaste causing any significant elevation of oxidative stress.

Triclosan: An antibacterial/antifungal agent used mainly to clean stuff. However, it has no reported antiviral activity. Heck, it’s even been shown that washing your hands with normal soap and water is more effective at removing viruses than washing your hands with triclosan, so… yeah. It’s probably pretty useless for fighting off the herpes virus.

Propylene glycol: Talk about a compound that’s found in all sorts of food products, from soda to ice cream. It’s used in toothpaste as a surfactant. No known anti-viral activity or anything cold sore related, as far as I can tell.

Diethanolamine: Used as a foaming agent in toothpaste and other things that foam. Again, it has no reported benefits for fighting off viruses, herpes of otherwise.

Hydrogen peroxide: A go-to oxidizer/bleaching agent/antiseptic. Mostly used in toothpaste as a whitening agent. Some idiots drink the stuff because they think it’s gonna “oxygenate the body” and thus “cure all the diseases”, including cold sores. Except it won’t. In fact, one of the few scientific studies linking hydrogen peroxide to cold sores found that the herpes virus contains catalase, which is an enzyme that can neutralize hydrogen peroxide by converting it into water and oxygen. So good luck fighting cold sores with the stuff.

Huh. I guess it doesn’t take a genius to see that there isn’t much cold sore fighting power in toothpaste outside of the sodium lauryl sulfate…

In a pinch and toothpaste is all you have? Here’s how to use toothpaste on cold sores.

I’m personally not convinced that toothpaste will do much to help fight off cold sores. It doesn’t hit one of the three targets you should be concerning yourself with when dealing with an outbreak.

But hey, if you want to try it, be my guest.

And if you’re in a pinch and toothpaste is all you can get your hands on, give it a shot. The worst that can happen is nothing at all.

The steps are pretty self-explanatory (stupidly so):

  1. Open toothpaste tube
  2. Squeeze some out on your finger
  3. Smear that shit all over your cold sore
  4. Wait and see what happens

Of course, there are a few finer points to consider:

  • Use it as soon as you feel symptoms coming on. Because SLS is the only ingredient with any cold sore fighting power in toothpaste and that it acts by essentially destroying the herpes virus, start using ASAP. Hypothetically, if you can catch it at the earliest stage possible, the better the odds it has of “killin’ herpiz” for you.
  • Use as much as you need to cover the cold sore (no shit, right?) and keep reapplying every few hours. I am gonna go out on a limb and claim (without any proof whatsoever) that once the toothpaste has fully dried on your lip it’s not going to do much beyond that point. Oh, and of course you’ll look silly because turquoise or white toothpaste is kind of hard to hide…
  • If you’re a little late to the party and oozing blisters are on full display, you can still give toothpaste a try (again, if you have no better alternative). I haven’t come across any evidence that it’ll help deal with blisters, but there is quite a bit of anecdotal evidence from people claiming that toothpaste has “dried out their blisters”. I dunno, maybe it does. You be the judge.
  • A lot of people say to only use a tooth-PASTE, and not the gel type stuff. Not sure why, since both the paste and the gel-types contain SLS (i.e. the only ingredient with any demonstrated anti-herpetic properties). But hey, the paste is usually cheaper, so you may as well use that anyway.
  • A lot of people talk about combining toothpaste with salt to form a sort of thick, grainy paste. Again, I couldn’t find any legit evidence supporting the idea of adding salt to the toothpaste. If I had to guess, I’d say the salt creates a sort of osmotic gradient that “pulls” out excess fluid from the blisters (like salting eggplant slices before making dat eggplant parmesan). Of course, it’s likely this is only useful if using toothpaste on the actual cold sore blisters and not so much during the early tingling stage of an outbreak. That being said, I’d definitely grind down the salt into a fine powder with a mortar and pestle, because rubbing rock salt on a painful cold sore doesn’t sound like much fun…
  • But the most fun part you’ll have is washing off the toothpaste once it has dried out into a tough, hardened crust (yay!). Soak it up as much as possible with water to soften it as much as possible before gently wiping it off. Because a hard wipe will probably do more harm than good.

So what’s the damn verdict? Toothpaste on cold sores, yay or nay?

So where does this leave us?

Can we answer the question “does toothpaste help kill those damn motherless abominations known as cold sores”?

I think we can definitely say “maybe”.

Lame answer, I know. But it’s da troof.

Sure, there is a bit of evidence that SLS does interfere with the herpes virus, but given the relatively low concentrations found in toothpaste, I’m not sure it does much at all.

I mean sure, if toothpaste is the only thing you can get your hands on, go for it. Just don’t expect a Jesus Christ-ian miracle.

But what about all the people claiming that using toothpaste got rid of their cold sore overnight, you ask?

My guess is, they were dealing with a fairly low viral load in the first place. And since the cold sore was pretty “weak”, the low amount of SLS found in their toothpaste was enough to fight off the herpes virus.

Then again, some of the people claiming it works used toothpaste in combination with a litany of other stuff too. So who knows if the toothpaste actually did anything.

Personally, I’d like to see toothpaste make a cold sore vanish overnight with my own two eyes.

Plus, for every story of toothpaste working, there’s another from someone who said it only made their cold sore worse.

But hey, put it to the test if you want. Who knows, it might work for you. And it’s not like it’ll cost you anything.

But I honestly don’t believe that it’s more effective than something like acyclovir, docosanol, or heck, even tea tree oil.

On the other hand, if you’re sick and tired of trying every damn cold sore remedy under the sun, sign up for the Incarsoreate newsletter below.

Because if you’re gonna go about trying every single treatment and household item on your cold sores, you’re in for years of suffering before figuring out what REALLY works.

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Chris "the Cold Sore Killer" Mueller