cold sores

Q. I have always suffered from terrible cold sores as far back as I can remember. I am especially vulnerable in the summer when I spend a lot of time outdoors. Even with lip balm that has a sunblock I am frequently in pain.
These sores are incredibly ugly and people always stare. That makes me even more self-conscious about them. What can you recommend to prevent cold sores or speed healing once they occur? I have heard that lysine might be good but I know nothing about this stuff. What is it and how well does it work?

A. Cold sores, also called fever blisters, can be painful and look yucky. Some people have outbreaks once or twice a year. Others seem to have recurrent lesions every few weeks. Once our bodies are infected with this herpes virus it remains forever. Why some people are more vulnerable to attacks than others remains mysterious. Clearly our immune systems play an important role in this process. Sun exposure can bring on an outbreak. So can a trip to the dentist (presumably because of mild trauma associated with such procedures).
Although we are enthusiastic about lysine (more about this supplement in a minute) we would be remiss if we did not mention that there are effective anti-viral agents for type 1 (HSV-1) herpes infections that cause cold sores. Zovirax (acyclovir) and Denavir (penciclovir) are available in cream form. Your doctor could alsp prescribe oral anti-virals as Famvir (famciclovir), Valtrex (valacyclovir), and Zovirax.
If you prefer a more natural and affordable approach, you may want to seriously consider lysine. The arginine/lysine theory of cold sore management remains somewhat controversial within the medical community. It goes something like this. The amino acid arginine is essential for herpes viruses to replicate and multiply. Arginine is high in nuts (such as almonds, Brazil nuts, peanuts, walnuts, etc), pumpkin and squash seeds, sesame seeds, red meat and some cereals (oatmeal for example). People are advised to cut back on high arginine-containing foods and add lysine supplements to their regimen (1000 to 1500 mg total daily dose). Lysine is supposed to make it harder for the herpes virus to replicate.
We were somewhat skeptical of this approach as there were been both negative as well as positive studies with lysine. Most of the research was with small numbers of patients and seemed inconclusive to us. Nevertheless, some of the double-blind, placebo-controlled trials lasted from 12 to 52 weeks and reported significant reductions in cold sore outbreaks among the lysine groups.
What has convinced us that something positive was happening with lysine has been the outpouring of letters from dental professionals and our readers. We have received so many anecdotal reports of success that we are convinced something is going on here We share just some of the lysine success stories with you:
One oral surgeon wrote to say his patients do well on a preventive regimen of one 500 mg tablet of l-lysine daily. If they develop a sore, increasing to four tablets a day seems to help it heal faster. A reader said, “I suffered from cold sores since I was a little boy and my doctor prescribed acyclovir, which wasn’t any help. My pharmacist suggested lysine, and I have been taking 500 mg of this amino acid for two years now. I am free of fever blisters and that’s a great relief.”
Q. When you wrote recently about home remedies for cold sores, why in heavens name didn’t you tell peple about l-lysine?
For 50 years I would develop fever blisters every time I went out in the sun. About 4 years ago a pharmacist told me about l-lysine. Since then I have taken it for a week before I know I’ll be exposed to sunshine. I have not had a cold sore since.

A. We were flooded with letters like yours praising the power of l-lysine. One young woman writes, “my boyfriend got these sores constantly, and as a last resort we went to the health food store to see if there was anything that could help. He was told to take lysine and the sores have never returned.”
Another reader reports suffering from nasty fever blisters that lasted 3 or 4 weeks. She was told by a friend to take lysine, and when she was skeptical the friend said, “then live with them if you’re stubborn.”
She now takes l-lysine whenever she feels a cold sore coming on or if she is in the sun more than usual. She says, “it quickly nips them in the bud. Doctors and druggists don’t seem to believe this, but I know it works.”
Judging from our mail bag, l-lysine does help many people. Though it may not work for everyone, this amino acid may be worth a try.
We would love to hear your story (positive or negative). Share your experience with l-lysine below in the comment section.

Join Over 90,000 Subscribers at The People's Pharmacy

Each week we send two free email newsletters with breaking health news, prescription drug information, home remedies and a preview of our award-winning radio show. Join our mailing list and get the information you need to make confident choices about your health.

  1. Amie

    Lysine for me has been a horrible experience – a friend has had a great experience with it but for me it has only made the coldsores worse and I have had constant coldsores all over my face for the last couple of months.

    I have an allergy to nuts and I think the lysine triggers this – avoid at all costs is my advice!

  2. Awix

    I was suffering from reoccurring cold sores pretty badly over the past 2 years or so. And I mean REOCCURRING. As soon as the outbreak would heal, I had one or two days, then I would have another outbreak. Sometimes I would get a two week break or so. But still that’s crazy! L-lysine in my experience does help. And the sooner you take it, the better. It was the end-all-be-all cure for me because I would have to take such high dosages of it, and had weird side effects (serious constipation). So I didn’t want to take it every day as a preemptive measure when the virus was in remission.

    My doctor prescribed me acyclovir cream. Which helps a lot, and is way more effective than abreva. Super cheap too! My insurance didn’t cover the name brand that came in the tiny, tiny abreva size tube. So I got the generic for ten bucks in a HUGE tube. Seriously it will last forever.

    However I am pleased to say I finally figured out what was causing my outbreaks, freaking ALMOND MILK. You know, the stuff I was drinking because I thought it was “better” for me. I always thought my cold sores were a byproduct of what I wasn’t putting into my body, I.e. Vitamins, eating enough fruits and veggies. Or that my immune system was somehow seriously compromised. Why else would this be happening?

    Nope, just the almond milk turning on me. I only drank the Kroger brand almond milk, and have since gone back to drinking regular milk. Not sure if those factors exclusively mean anything, but I’m not going to find out. my cold sores are gone, and that’s brilliant. I’m sort of kicking myself for not realizing it sooner. Though I did learn a few tricks on how to handle out breaks.

    I got the entire thing down to only a three day heal time. the second you think you have a cold sore, PUT ICE ON IT. seriously, I always read this, and ignored it, chalking it up to just being for the pain. But it will take the severity out of your out break if not sending it into remission. I’ve had a pulsing spot dodge becoming a gross blister into a hardly noticeable scab. Completely skipping the stages of the blister forming, weeping, and crusting. The acyclovir ointment helps when you can’t ice (I will sit around my apartment for thirty minutes at a time with ice wrapped in a paper towel on my face to ensure nothing would continue to blister). Taking l-lysine while icing and using the acyclovir ointment is a big help as well. Any way. Sorry for such a long post! Some some things I’ve learned.

  3. Lynn

    I’ve had cold sores all my life. Very bad cold sores. Right now I have one on my bottom lip and two huge ones inside my mouth – only the second time that’s happened. They are horribly painful and my glands are sore and swollen. In the past few years I have had more and more breakouts. I know the sun is the worst offender for me and I don’t leave the house without a hat in summer. The dryness of the city I live in doesn’t help either. It’s interesting that the article said a trip to the dentist could cause an outbreak because I just had a root canal done (more fun) and then I got these lovely sores.
    Something that does work for me is camphor spirits. If I can put that on my lips the minute I feel the tingling, it usually stops a breakout, or at least I break out with fewer and smaller ones. You have to keep putting it on until you are sure you aren’t going to break out. It does smell and it does dry out your lips, so you have to put a lip balm on as well. Occasionally though, the cold sores are just determined to come out and nothing can stop them. The camphor spirits help to dry them out once you have a breakout. It also stings, which for me, actually reduced the pain of the cold sore.
    I am going to try L-lysine though, because I used to get them maybe once a year and now it seems like once a month.

    • Mike

       I have had cold sores since I was a small child when our grandmother kissed me and my four sisters. I’m a PT and golf instructor and I am outside for 8 months a season and used to get several outbreaks per season. I spent hundreds on Abreva and Valtrex. What a waste of money. I take L-Lysine every night and haven’t had a breakout in over two years. Knock on wood. I use a 60 lip balm religiously and 60 sunscreen. L-Lysine is rather cheap compared to all the prescription meds. It works for me.

  4. Nick

    I suffered from 2-3 horrible cold sores a year for 10 years, they were huge and very painful/embarrassing. Nothing would help them and I’d have to wait two weeks for them to clear up. I started putting a bit of abreva on the spots they would occur about once a week or every two weeks and have not had an outbreak in 2 years. Don’t know why it works but I’m sure glad it does.

  5. Kathy

    My young son would get recurrent cold sores. He would heal up and then a new one would come on within a few days. I think for every school picture from 1st grade through 5th he had a cold sore. Finally I decided to see if going with a gluten-free diet would help at all. It was just a shot in the dark and occurred to me only because I myself had gone to a gluten-free diet (for a different reason) and felt so much better. Well, it did the trick — no more gluten, no more cold sores. By now, at age 15, he is well aware of how much gluten he can get away with eating (a few non-gf chicken tenders once a week, for example). I suspect that his system had been sensitive to gluten and therefore was constantly in a state of immunodeficiency and just couldn’t suppress the virus. For someone else, it might be a different food(s) that causes the same. His pediatrician tells me no way did gluten have anything to do with his cold sores… I just give a half smile and remind myself that we see her only for purposes of school physicals and immunizations. (Sorry to say that even though I have been eating gluten free for 10 years now, I ‘ve been suffering for at least a year with recurrent cold sores. Interestingly, I’ve just been diagnosed with fibromyalgia… I know my immune system is just not right.)

  6. Adam
    New Jersey

    Some people say you will have fewer outbreaks when you grow older. It wasn’t the case for me. Maybe the stress from work and poor sleeping schedule, I had frequent outbreaks. It was totally embarrassing. I tried almost all of medications that my doctor could prescribe for me. I read every site I could find, hoping for magical remedies. Some of them seemed helpful, but nothing worked for long. The next one came out sooner and sooner. Side effects of medicine started to show on me: itchy skin and constantly itchy lips. Last May, I made a purchase from homemedlab for something else, and surprisingly got a free sample of cold sore control, which was actually not listed on their website. I was ready to try anything at that time, so I used it right away. It says vegetable and fruit based, and does smell like fruits. This sample stopped the itch on my lips within a few days. In the following months, I just applied a little on my lip, whenever I felt the monster was coming again. Every time, it stopped it, mostly overnight. I am feeling cold-sore-free now. The sample is not listed in their website, but if you have tried everything else and are desperate like I was, it is worthy to ask for a sample from the site.

    • alan

      Hi Adam, please cut a fresh ginger root and use it like lipstick on your kids lips every day if he has the cold sore or not —Every day you will see a miracle …. Good luck and Shalom!

  7. Sara

    For a year and a half, I was getting at least one cold sore every month. I tried EVERYTHING: zovirax, lysine, red marine algae and every “get rid of it fast” remedy I could try. It was starting to depress me. Especially when I got 3 IN ONE MONTH. I thought long and hard about what changed in my diet over the past 1.5 years and the only thing was my caffeine intake. I never used to drink coffee and I started almost every day, plus I was drinking pre-workout drinks that had a lot of it. I cut caffeine out of my diet and I haven’t had one in almost 5 months. Try it!!! It’s so worth it.

    • Adam

      Some people say you will have fewer outbreaks when you grow older. It wasn’t the case for me. Maybe the stress from work and poor sleeping schedule, I had frequent outbreaks. It was totally embarrassing. I tried almost all of medications that my doctor could prescribe for me. I read every site I could find, hoping for magical remedies. Some of them seemed helpful, but nothing worked for long. The next one came out sooner and sooner. Side effects of medicine started to show on me: itchy skin and constantly itchy lips. Last May, I made a purchase from homemedlab for something else, and surprisingly got a free sample of cold sore control, which was actually not listed on their website. I was ready to try anything at that time, so I used it right away. It says vegetable and fruit based, and does smell like fruits. This sample stopped the itch on my lips within a few days. In the following months, I just applied a little on my lip, whenever I felt the monster was coming again. Every time, it stopped it, mostly overnight. I am feeling cold-sore-free now. The sample is not listed in their website, but if you have tried everything else and are desperate like I was, it is worthy to ask for a sample from the site.

  8. debi

    I suffer with coldsores a lot I av just gone and bought l-lysine I really hope they work fingers crossed .

  9. John

    Ive dealt with them my whole life – usually 1-2 a year, but they would be really bad when i got them. Like 2 weeks to heal. Lysine never worked for me personally. Doc gave me a Valtrex prescription about 10 years ago and its made a world of a difference. As long as i take 2 1gm pills twice a day right when i see it, it never gets bad, and is gone in 3 days or so. I make sure to have a few on me at all times.

    However, just recently, im dealing with a bout of back to back breakouts – like 4 straight weeks now. The prescription is still preventing them from becoming bad, but the recurrence is frustrating. Im wondering if my immune system is down or something. My diet and stress has caused problems in the past, but never this many. In the last 4 weeks, I’ve gotten more than i had in the previous 4 years.

    • Kate

      Hi John. I too have never found lysine to be helpful but i was also taking Valtrex which was a godsend! I kept getting frequent outbreaks however so went to a new doctor for help. He prescribed me with aciclovir tablets which I now take daily. I have only had 2 coldsores in the 8 months I’ve been taking this medication. I was getting multiple coldsores every week beforehand. Much cheaper than Valtrex and I’m a new person. Hope this helps you!

  10. Dawn

    I used to get cold sores about twice a year. Then someone told me about L-Lysine-I started taking it and it seemed to work well for a while. I take L-Lysine every day and for the past 8 months I have been getting cold sores about every 6-8 weeks! I am so tired of this…

    • Jim
      BC Canada

      L-Lysine does work great, BUT, you don’t take it everyday or the effects will fade overtime. What you do is take it as soon as you feel the tingling of the sore under the skin. I take 400-600mg in capsules with a glass of water. Then place an ice cube in a paper towel and place the exposed side against the skin at the location of the sore and hold it there until the skin is numb. Wait until after the burning cold feeling goes away. I have been doing this for the past 3 years now and have not had 1 cold sore since! Not one. Stay out of the sun mostly and if you live somewhere with cold winters, cover your lips with a scarf/windbreaker when you go out to reduce stress to the skin that can trigger the sore.

  11. ashley
    Kalamazoo mi

    I used to get cold sores twice a year, one when it got hot outside, and one when I got cold outside. They were often big and ugly, but since starting lysine tablets, I havent had one! I don’t even have to take them every day. Only when I feel “the tingle” or when the area I normally get them starts to look red. I also couple that with an application of abreva, and viola, no cold sores for a year now. I’m a believer!

    • Jim
      BC Canada

      Same here! It works great. I am living proof. Just take when the tingling comes.

  12. Stephanie

    I’ve noticed when I eat/drink oranges, OJ, grapefruit I break out. I don’t know if it’s just coincidence but I love these foods especially in the summer but try to avoid them as much as possible. I’m going to try icing it and I’ve heard garlic works too. Has anyone tried garlic directly on a cold sore?

  13. Chloe

    After reading this chain and seeing all the comments about icing early cold sores gave it a go this morning. Have been getting them for 3 years now and lately they have been continuous, its awful. Zovirax, aciclovir tablets and lysine have not worked. Happy to say that after icing my lip for 2min this morning (followed by zovirax ointment) the 2 new sores have completely disappeared!!! Will repeat this afternoon, fingers crossed they stay away.

  14. Jodie
    United Kingdom

    I regularly get cold sores. I have been using compeed cold sore patches. These are great, but can be noticeable when I am wearing foundation & make up. I always get them when exposed to the sun. I need a quick remedy to get rid asap.

  15. Haley

    In the beginning stages of getting a zit under my nose, I thought it was a cold sore. I started taking an antiviral once to twice a day, and taking lysine twice a day, as well as rubbing abreva on the spot. Even though it just turned out to be a blemish, I was continually doing everything you can do to prevent and treat a cold sore when I woke up with a cold sore on my lip. It made me want to cry. Not that I’m going to give up, but it seriously makes me doubt there is anyway to actually control this. I will say since I discovered antivirals I at least don’t get cold sores as giant and scarring as the ones I got in childhood when no one was looking how to really take care of this for me. But even with the time and money I’ve put into trying EVERYTHING as an adult, I’ve been 100% unsuccessful at actually preventing an outbreak.

  16. ashley

    I first had a cold sore in the middle of my first pregnancy. I have no idea how I go them. I struggled for over two years with constant reoccurring breakouts. I started dealing with it by taking lysine. At first it seemed to help but soon seemed to be little help and I was still having frequent outbreaks, at least once a month. So I asked my doctor for a prescription of Valtrex. Since on valtrex, one year now, I have had three minor outbreaks, I think mainly due to missing a dose. It has been very effective for me. I take just 500mg a day. I hope to go back to something more natural but this is all that works for me currently. Lysine wasn’t effective enough for me

  17. Corey

    For me, lysine definitely worked. I started taking lysine and didn’t have a breakout for a year and a half. When I did sense a breakout, I pumped up the dosage and the cold sore wouldnt be that noticeable. But, now the problem is, I just moved to Colorado and I’ve been getting chronic cold sores. I’m not sure if it’s just my body acclimating to the dry environment or if my body has become immune to the lysine. Hopefully, it is just me adjusting.

    • Lisa

      I was doing well in Florida. I was going to the beach and the sun for a change wasn’t bothering me at all. Now that I have moved to Colorado, been here a month, I am already on my second outbreak! I am starting to think it has something to do with Colorado also.

      • Jess

        I also came to Colorado from Florida last year, and was in Malaysia before that. Almost a year with no outbreaks. Since coming to Colorado I’ve had an outbreak every month like clockwork, & no idea why. I eat well, and get more exercise than I have in a while. Totally stumped, too! Could it be the altitude??

        • Peg

          I’ve had recurrent cold sores since I was a young girl (the past 30 years). This is what I’ve found most helpful …

          Treatments for fever blisters / cold sores

          Daily preventive regimen:
          RX Valtrex 500mg suppressive therapy
          L-Lysine 1000mg tablet
          L-Lysine lip ointment
          Meditation & relaxation exercises
          Clean eating & whole food diet
          Super Lysine Plus Lip Clear Coldstick With SPF 21 when outside & exposed to sunshine

          Treatment for an acute breakout:
          Valtrex 1000mg twice daily x 1 day
          L-Lysine 1000mg tablet 3 times daily x 3 days
          Lysine lip ointment
          Zinc oxide ointment
          RX Xerese cream (acyclovir & hydrocortisone) 5x daily x 5 days … this is an expensive prescription, so ask your physician to prescribe Zovirax cream if your insurance won’t cover Xerese.
          Compound RX cream from local pharmacist: clobetasol & tetracaine (corticosteroid & anesthetic) 3x daily … this is extremely helpful for pain & my local pharmacy charges $20 for a 5 gram syringe … ask your physician to prescribe a compound like this with a *caine medication mixed in to numb the pain of the cold sore.

          Someone told me to try this if I have another outbreak:
          Extra Zinc tablets (15-30mg) daily x 1 week

          If I have an outbreak, it’s usually related to increased stress or excessive sun exposure. Know your triggers (internal & external).

          Hope this list is helpful & gives you other things to try as preventive measures & treatment. ~ peg

  18. sherley
    rochester ny

    I use l-lysine- tea tree oil – garlic fresh- vanilla extract- alcohol- coconut oil-honey to no avail as soon as the first one started to heal up under my nose I got 3 more pumps on my lip I never eat nuts or bread put I just started eating fresh pineapple and the next day they started and I have been eating it everyday for the vitamin c I wonder if that’s what causing it?

  19. Alex

    So this may sound extremely out there, but I’m almost certain the Gummy prenatal gummy vitamins from Target keep my cold sores dormant. It could just be taking any multivitamin will do the trick of a lack of nutrients is causing your cold sores. The prenatal ones are just the ones I’ve always taken (for the extra benefits they provide for your skin and hair). But before I figured this out, I was suffering from persistent, reoccurring cold sores in the year and a half I stopped taking the vitamins. I would get one, it would heal, two days later a new one would sprout up on the other side.

    That being said, I figured out a pretty solid regiment for getting a cold sore gone fast. It’s even kept them from blistering. The second I feel a tingle I take a lysine. After I know for sure its a cold sore, I take two more. And then continue taking two every 4-6 hours. I also take extra vitamin c and zinc to boost my immune system. (Always take with a meal, or you may get sick, and drink LOTS of water.) I also ice the spot as much as possible, especially after a nice warm shower. I used to never do this, but gave it a shot and found it to truly be a game changer. I also put on abreva just for peace of mind when I’m out and about.
    Hope this helps!

    • Haley

      I religiously take multivitamins (very specifically the prenatal a from target as well) and can tell you they don’t work, unfortunately. Though boosting your immune system can only be helpful.

      Pineapples, especially fresh, tends to really (tear up) your mouth. The acid causes tiny abrasions in your mouth, and then cold sores take advantage of your immune system being diverted taking care of that to set up shop else where around your mouth.

What Do You Think?

We invite you to share your thoughts with others, but remember that our comment section is a public forum. Please do not use your full first and last name if you want to keep details of your medical history anonymous. A first name and last initial or a pseudonym is acceptable. Advice from other commenters on this website is not a substitute for medical attention. Do not stop any medicine without checking with the prescriber. Stopping medication suddenly could result in serious harm. We expect comments to be civil in tone and language. By commenting, you agree to abide by our commenting policy and website terms & conditions. Comments that do not follow these policies will not be posted.