Q. More than 20 years ago I came across an article promoting l-lysine as a preventive measure against cold sore outbreaks. Having suffered with this virus since adolescence, I was motivated to try the supplement.

In my experience, l-lysine is a miracle drug. I used to have at least one outbreak a month, but I now only feel the initial “tingle” of a cold sore if I have overindulged in caffeine, been under an abnormal amount of stress or spent too much time in the sun. I take 1000 mg a day, every day. If I feel an outbreak coming, I triple the dose for a couple of days and the outbreak is prevented.

A. Many people report, like you, that l-lysine seems helpful in preventing or healing cold sores. Double-blind studies on l-lysine for cold sores have produced mixed results. There has been surprisingly little research in recent years, however. This amino acid appears relatively safe although some people report digestive upset.

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  1. J
    uk
    Reply

    I wanted to add my thoughts to this discussion as I had really good results using l-lysine. I have had coldsores for many years. I have used the usual creams to reduce healing time and whilst I am sure they have I haven’t ever been able to stop a coldsore from developing.

    On Thursday I got a little bump on my lip. I never get the tingling or anything so it was difficult to know either way. I put the usual cream on but by Friday morning it was obviously a coldsore. I had got the swelling and all that comes with it. I continued using the cream and took 1000mg l-lysine.

    To be honest didn’t expect to any results. I got a few digestive side effects but nothing too bad. The swelling reduced and the blisters didn’t seem to form. I just had a mark above my top lip that looked like a very mild coldsore. I still experienced the itching etc but not a lot else.

    Woke Saturday morning to find the coldsore didn’t look like a coldsore anymore. On close inspection I had I could see a pink area with a fraction of it covered in what looked white a little like dry skin. From a further distance it looked like a blemish or something. Nothing further developed. Sunday morning – I again have a pink patch with little white parts. I looks a little like mild patch of eczema or a little chapped.

    I only took the one dose of lysine as I had to go out on Saturday and didn’t want the digestive upset. L-lysine has worked so well for me. My coldsores are normally so bad and follow the usual pattern; at this stage it would be angry, red and oozing. I have none of that. I won’t take the lysine on a permanent basis as I worry about the side effects of doing so but will use at the first sign of a coldsore. I am very impressed with the results. I also wanted to say from what I have read there are some people who shouldn’t take lysine so I would advise reading and getting good advice.

  2. wpsmithjr1041
    Reply

    I get cold sores from time to time. One right below my lower lip. From all the reading I have done, you probably shouldn’t supplement with lysine everyday, unless you don’t get enough in your diet. Avoid nuts, peanut butter, tomatoes, and acidic foods.
    Some people say they haven’t been getting results but they’re only taking 500 milligrams or 1000 milligrams. When I feel a sore coming on, that little tingly feeling and the little bump starting to form, I immediately take 4000 to 5000 milligrams of lysine.
    I accidentally took twice that much one time when I thought I was consuming 500 milligram tablets and they were 1000 milligram tablets. I puked my guts up and had diarrhea the rest of the day. I don’t recommend that. But 4-5 thousand milligrams never has bothered me, but it has prevented every single cold sore from forming when I catch it quickly.
    I keep the lysine in my car and in my bathroom at home. I always have it with me, and if I feel that tingling feeling, I immediately pop 4 1000 milligram tablets. After a few hours I take about 2000 milligrams. Then later 1000. And then I make sure I take at least 1000 milligrams for the next 2 or 3 days. The sores never form if I do this.

  3. CC
    Reply

    I stumbled across Lysine for cold sores a couple of years ago. I started using whey protein shakes that had it in it and I would hardly ever get a cold sore and if it I did, it was def less intense and only would last 2-3 days. No eruptions and it wouldn’t get all nasty looking. Surprise, surprise, I stopped taking drinking the shakes and I’m back to having them every single time I get too tired, sick, or stressed.
    The lip balm works great too and I just picked up another bottle of pills today!

  4. LS
    Reply

    Hello—–I am considering taking L-lysine daily, and I keep seeing it is recommended for up to one year. What do I do after a year? Never take it again…..or take a short break and then go back to it? Would greatly appreciate info on that!

  5. Ema96
    Reply

    @DMC
    I also just bought my bottle of Lsine today. I have have read so many, many comments (in different forums that taking 1000mg every day to prevent an outbreak is much more effective than taking 500mg.) on how people take 1000mg every day, 500mg in the morning and 500mg in the evening. So I plan on doing that.
    It doesn’t work when you having an outbreak but it works pretty well when you are taking it everyday to prevent outbreaks. I would start taking my tomorrow.

  6. DMC
    Reply

    I recently purchased my first bottle of lysine pills and am deciding how to take them.
    Some people here are saying they take lysine the moment they feel a cold sore coming on. My cold sores erupt way too quickly for this to be practical. From the initial tingle/soreness I only have about 2-3 minutes until the first blister appears. 10-15 minutes later and it’s a full blown cluster of blisters.
    So the second I feel the tingle/soreness I immediately have to drop everything I’m doing to have any chance of “catching” it (I apply acetone to the affected area). Taking lysine pills at this point feels like it would be far too late. Even if I took some the second I felt the tingle/soreness, I can’t see how it would work in time.
    What I’ve decided is to take 500mg per day as a preventative measure. Any thoughts on this?

  7. cft
    Reply

    I am 46 yrs old / been getting these damn things for forever (my parents also suffered from them when I was little (70s). We used to drink after my parents) my brother & sister never got them. A friend told me about l/lysine (500mg) about 10 yrs ago & it does work pretty good. Maybe it doesn’t completely take it away but it does reduce it.
    About 3 yrs ago a dr. prescribed 500 mg valtrex & that works a lot better. Stress & sun is what does it to me (occasionally heat. Sometimes I have to weld or burn for work) or if I get sick & have a fever, that will kick me off too.
    W/ the valtrex if I’m able to start it as soon as I realize it will keep it at bay (nose). My problem today is I didn’t realize what it was until it was too late (thought it was a pimple). I’ve been married 16 yrs now ( wife does not get them / were both careful) & I got a big cluster right before my wedding (pool & stress) so I have to look at every pic of my wedding remembering not to mention it put a damper on the honeymoon.
    So bottom line is I feel for anyone who is fellow sufferer. My wife mentioned to me last night that she heard that eating a yogurt or taking a acidophilus wafers could keep them away, this will be the next thing I try, goodluck // cft

  8. JL
    Reply

    Why it works: I’ve read that herpes can only be triggered into an outbreak if arginine builds up in nerve endings. Lysine can also build-up in nerve endings, displacing arginine from accumulating there. So if you ingest more lysine than arginine then outbreaks are prevented. Keeping diet in a lysine+ balance or using lysine supplements does the trick. For people taking lysine daily and still having occasional outbreaks,avoid the foods at bottom of list linked below.
    Recently also had success stopping an outbreak in progress. Had tingling and then could see and feel a bump on lip 1/4 inch in diameter. It hadn’t blistered yet. Took 3,000 mg of lysine and the bump disappeared in 2 hours. Did have a negative side affect though – moderate abdominal cramps later. Afterwards read that high doses of lysine can interfere with certain antibiotics (streptomycin & a few others) so beware of this and other possible medicine interactions.
    Here’s a list of foods with lysine/arginine ratios: http://www.herpes.com/Nutrition.shtml

  9. Helpful Tip
    Reply

    I just healed what I believe would have been a large coldsore in ONE day. I started getting it on Thursday night – and by Saturday there was NO SIGN of it.
    Here is what I did.
    As soon as I felt the tingle and saw the blister starting to form I took a sandwich size ziplock bag and filled it with ice. I twisted the bag so that the ice was pressed into the bottom and used a towel to hold the bag. I placed the bag on my lip for 20 minutes. At first it was very cold, but then my lip numbed up and I could not even tell it was cold. I repeated this about 2 hours later. I woke in the middle of the night and did it again – 20 minutes, and went back to bed.
    Very first thing when I woke up, I did it again. Then about 2 hours later did it again and went to work. When I got home, I did it again, but only for about 15 minutes.
    Sure enough, I froze it out – and it never even scabbed and today (Sunday) you can not even tell I ever had a cold sore.
    I read on this forum about someone using ICE – and I tried it. After 20 years of suffering – it is the only treatment that healed me that quickly.
    (I also took 2,500 mg of Lysine in the AM and PM the first day, and 2,000 mg in the AM and PM the next day.)
    Try the ice – it gives you a bit of headache – so you may want to do 10 minutes, wait 10 minutes and finish with the remaining 10 minutes. Do it 4 times a day for two days and let us know how it works!

  10. K.M.
    Reply

    My particular nightmare is an outbreak at the base of my nostril. I’ve only recently discovered the promise of L lysine, so have not used it aggressively yet. I’ve had about 7 outbreaks over the last few years, and always there at the opening of my nose (?). It’s absolutely traumatic as it’s going through its cycle, because the scabbing over part looks so much like a big bugger! I’m sure people see it and wonder if I know it’s there or not, should they tell me or not (like the emperor with no clothes!), how disgusting and mortifying for both parties! So, I too, just TRY to hide out, which is not always possible. Or wearing a surgical mask and feeling another kind of conspicuous. !! Now, I’m gonna try this most-hopeful new treatment of L Lysine, and also some of the other ideas on this site. I’m also gonna keep a written record of future results and plan to post them here eventually….
    My sympathy and best wishes to all of you, my fellow sufferers. You’re not alone.

  11. Barrington
    Reply

    I have taken 4 1000mg to 5 daily once one appears it stops it in its track and doesn’t get worst it starts the healing. The min you feel it tingling take 4x1000mg and it won’t break the skin those small doses aren’t enough to percent out from breaking skin. I am a semi expert now have taken everything.

  12. Ashley
    Reply

    If you’re trying to prevent getting cold sores, you need to understand that lysine prevents cold sores and ARGININE exacerbates getting them. Food items high in arginine are chocolate, nuts and oranges. So if you’re breakfast is OJ and cocao, you’re actually hindering yourself and making it worse. Look up lysine and arginine foods. It’s best to stay away or eat less of it to prevent cold sores.

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