Does Abreva work, or does it drag cold sores out?

Abreva. Probably the most marketed cold sore treatment ever. And I wouldn’t be surprised if it was the best selling, too.

But if you feel a cold sore coming on, or are fighting a nasty outbreak right now, you don’t care about how much money GlaxoSmithKline are raking in from Abreva.

All you want to know is, does Abreva work.

Because I’m guessing you don’t want to drop 20 bucks on another useless cold sore treatment. You want something that will stop your cold sore dead in its tracks, or make it vanish as soon as physically possible. You want to know if Abreva really works or if all the hoopla surrounding it is just empty hype.

To help answer that question, I dove deep into the stuff to figure out what the active ingredient in Abreva is, what kind of scientific proof there is behind it, how long it takes to work, and at what stage of cold sores it works best on.

So keep reading to find out if Abreva actually works on cold sores or if you’re better finding a more potent alternative.

Abreva ingredients

Before we can figure out if it works, we have to know what the active ingredient in Abreva is.

A quick look online reveals the following list of ingredients in Abreva:

  • n-docosanol
  • benzyl alcohol
  • light mineral oil
  • propylene glycol
  • purified water
  • sucrose distearate
  • sucrose stearate

Most of those ingredients are inactive and are utterly useless against cold sores and/or the herpes virus. But the main active ingredient in Abreva that grants it it’s cold sore stopping powers is the n-docosanol.


Also known as benehyl alcohol, docosanol is, in sciency terms, an aliphatic alcohol that has been shown to have antiviral activity against multiple lipid enveloped viruses such as the herpes simplex virus (i.e. the cold sore virus).

Question is, is docosanol cream effective for stopping cold sores or making them go away faster than they would otherwise?

To answer that question, let’s first take a look at docosanol’s mechanism of action to learn how Abreva works.

How does Abreva work?

Docosanol doesn’t work like most other antiviral cold sore treatments. Instead, it works by stopping the fusion between the plasma membrane of the skin cells it targets and the envelope of the herpes simplex virus itself. By extension, it prevents viral entry into healthy cells and any subsequent viral activity.

See, the herpes virus isn’t technically alive (neither are other viruses). To be able to replicate itself and cause cold sores, it needs to hijack the cellular machinery of the skin cells in your lips. And to be able to use that cellular machinery, it first needs to get inside a healthy cell. If it can’t get inside, it can’t replicate and it can’t cause cold sore symptoms.

One of the steps taken by enveloped viruses such as the herpes virus to enter cells is fusing its membrane with the membrane of a healthy cell. Kind of like two soap bubbles fusing together to make a bigger, soapy bubble. Whatever is inside each bubble get mixed together.

So, docosanol cream works by blocking the ability of the herpes virus to attach itself to healthy cells. The idea being if it can’t attach itself to a healthy cell, it can’t enter it and therefore can’t do any damage.

Does Abreva really work?

Now that we know how docosanol and Abreva works, let’s take a look to see just how effective it is at preventing or healing cold sores. To get a full picture of its effectiveness, we’ll look at what the scientific evidence being docosanol and what actual cold sore sufferers have to say in user generated Abreva reviews.

Does docosanol work, according to science?

First, let’s look at a study published in 2002 to figure out if docosanol is effective against cold sores and how many days it can take off an outbreak.

In this case, the researchers split the cold sore sufferers into two groups. One group would get 10% docosanol cream, and the other group would get a placebo. Each treatment group would apply their respective cream 5 times per day.

The researchers found that the docosanol cream reduced the time it takes to heal a cold sore by a whopping 18 hours on average. While that’s nothing to scoff at, it’s not exactly groundbreaking.

Plus, it turns out that there were a few issues with this study which were raised by other scientists after it was published.

The biggest issue was that the scientists used a different control vehicle as a placebo than in the docosanol group.

You see, normally, to test whether docosanol is truly effective at stopping and healing cold sores, it would have to be the ONLY thing that changes between the docosanol treated patients and the placebo treated patients.

The inactive ingredients, so to speak, need to be identical. But in this case, they weren’t. So the question is, was the difference in healing time strictly caused by the dcosanol, or did the different inactive ingredients play a role ? There’s no way to know.

But really, that’s just one study.

The full spectrum of evidence on docosanol ranges from it being as effective as aciclovir to it being no more effective than a placebo. Some studies find it reduces healing time by a full day, others claim it does nothing at all.

So where does the truth lie?

According to a comprehensive review published in 2010 of all the scientific literature available on docosanol cream, it was concluded that docosanol is a safe and effective treatment for recurrent cold sores. Let’s leave it at that.

How long do cold sores last with Abreva?

According to the 2002 study we talked about earlier, patients treated with docosanol cream had  a median healing time of a little over 4 days, while those treated with the placebo had a median healing time of a little under 5 days.

Now, I don’t have all the details of the study, but having suffered through more cold sores than I can count, I have to assume that what the researchers call “healing time” is from the start of the cold sore to the end of the blister stage, when a crust forms. Because I’ve never seen an un-treated cold sore go from tingling stage to being fully healed, gone without a trace, in under 5 days.

In my experience, how long a cold sore lasts with Abreva really depends on how bad the outbreak was in the first place. A tiny cold sore may heal in 4 or 5 days. But big nasty cold sores that cover half your lip take a whole lot longer than that, Abreva or no Abreva.

How fast does Abreva work?

Finding concrete scientific data on how long it takes for Abreva to work proved to be difficult. The scientific studies on docosanol mostly report things like cold sore healing time and how big the cold sores get with Abreva on average.

But given that it’s a topical treatment, you can assume that the docosanol in Abreva gets to work as soon as it gets absorbed by the skin. So we’re talking minutes.

Of course, how fast you start seeing results depends on a lot of factors. How many times per day are you applying Abreva, how big of a cold sore you are dealing with, how early in the outbreak did you start using Abreva, etc. It’s going to be different for every cold sore and for every person.

That being said, based on user reviews of Abreva, the general consensus is the earlier you start using it, the better results you get. Based on that info, one can only assume that the docosanol inside Abreva starts working as soon as you apply it.

Does Abreva work after the blister appears?

Based on how Abreva works, once your cold sore blisters are out, proud, and there for everyone to see, Abreva isn’t going to do much.

Docosanol works by preventing the herpes virus from infecting new, healthy skin cells. When the cold sore blisters are already out, the viral infection is at its peak. The virus has basically infected as many cells as it’s ever going to.

So stopping new cells from being infected isn’t going to do much for cold sores already in the blister stage beyond perhaps stopping them from getting even bigger. Just don’t hold your breath for Abreva to have much of an impact on existing cold sores.

Abreva reviews from real life cold sore sufferers

If science has found docosanol to be an effective treatment, what do real life cold sore sufferers have to say?

Just like the scientific literature, user reviews of Abreva are all over the map. Read reviews on Amazon or stories from people on Reddit and it seems Abreva is either the greatest cold sore medicine ever, or it doesn’t do anything. Heck, some people claim that it even made their cold sores worse!

But given that the positive reviews of Abreva generally outweigh the negative ones, it’s safe to say that it’s effective more often than not.

As for those claiming that Abreva made their cold sores worse, well, how do they know?

When you’re treating a cold sore, you don’t know how big it would have gotten had you left it untreated. So even though you get big, nasty blisters with Abreva, how do you know they wouldn’t have been even bigger and nastier without the Abreva?

Plus, I seriously doubt that Abreva can actively make a cold sore worse. My guess is the people who said so in their reviews either didn’t use it early enough in their outbreak, or they would have gotten an outbreak twice the size had they not used it.

Are there any Abreva alternatives?

Ever since it’s been available, Abreva has been basically the only cold sore treatment containing docosanol on the market. I can only assume that’s how they’ve gotten away with selling it for twenty bucks a tube for so long, when all the other over-the-counter cold sore treatments sell for half that.

However, there is now an alternative to Abreva, and it costs significantly less money too. It’s called Docoshield.

Like Abreva, Docoshield contains docosanol as its active ingredient. The big difference between both products, though, is that while Abreva is designed more as a treatment you use when your get a cold sore, Docoshield is a lip balm designed for everyday use.

Is it better than Abreva? Well, given that it contains the same active ingredient, I don’t see how it can be all that much better.

That being said, it’s designed for everyday use. And if you apply docosanol on your lips every single day, even when you don’t have the slightest hint of a cold sore, you’re virtually guaranteed to catch any potential outbreak long before you get that tingling sensation. In that sense, Docoshield is like having armed guards constantly patrolling the perimeter of your house for criminals, while Abreva is like calling the cops after a burglar broke a window and sneaked into your house.

Plus, for roughly the same price as one single tube of Abreva, you get three Docoshield “chapsticks”. So at the very least, it’s easier on the wallet.


When it’s all said and done, the only thing that matters to you is whether or not Abreva will work on your cold sore.

Based on my research and my own painful experience with cold sores, I can say that it does what it’s supposed to do, i.e. prevent the herpes virus from entering healthy cells.

That being said, I do have to question its use as the only tool you should be using against cold sores

See, docosanol may prevent the herpes virus from infecting new cells, but it doesn’t do anything for cells that are already infected. And as soon as you feel that tingling sensation, it means that the herpes virus has already made its way into the skin cells in your lips.

So while Abreva can very much help limit the spread of your cold sore, in most cases it won’t stop a cold sore from forming completely because you only start using it after the infection has taken hold.

But really, the only way to know for sure if Abreva really works is to try it for yourself. So for your next cold sore, start using it early, and use it often. That’s the only test known to man to really find out if Abreva works for you.

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Chris "the Cold Sore Killer" Mueller