L-Lysine Benefits and Side Effects - Vitamin & Herbal Supplements

L-Lysine Benefits and Side Effects

lysine for cold sores

Lysine may help with cold sores.

L-Lysine Benefits and Side Effects

Lysine is one of eight essential amino acids – building blocks of protein – that the body cannot manufacture on its own. L-lysine is a specific configuration of the lysine molecule often used in dietary supplements.

As a building block of protein, l-lysine benefits the body by contributing to growth.

L-lysine benefits also include production of carnitine, a substance that converts fatty acids into energy and lowers levels of LDL (“bad cholesterol”) in the bloodstream.

In addition, l-lysine benefits the skeletal system by contributing to the production of collagen, the protein used to make bone, tendons, cartilage and connective tissue. Calcium absorption and use is also facilitated by this supplement, which also benefits the skin by helping to maintain its health and elasticity.

Lysine Deficiency

Without enough lysine in the diet, a range of health conditions may result. Though most people can easily obtain sufficient amounts of this critical amino acid through diet, those who eat large amounts of sugary cereals and baked good may minimize l-lysine benefits.

This is because lysine is involved in the browning of sugar, which occurs when the two substances bind together. As a result, it is difficult for the body to absorb the lysine in sugary foods. So, in cases where a person’s diet is high in foods that contain a lot of simple sugars, supplements may be of use.

There may be other l-lysine benefits from supplements for people with specific health concerns.

Specific Health Concerns; Cold Sores and More!

For example…

… when taken with vitamin C, l-lysine appears to help symptoms of the heart condition angina pectoris. It has also been used to treat sores caused by the herpes simplex and herpes zoster viruses.

Most of the feedback we’ve received (see comments below) pertain to lysine’s ability to treat cold sores; many people are very happy with the supplement in this regard.

Additionally, it is believed that l-lysine benefits people with osteoporosis by helping to prevent bone loss.


As mentioned before, calcium absorption appears to be enhanced by this amino acid.

Also, since low levels have been associated with depression, chronic viral infections, asthma, and low levels of thyroid hormones, there are possible l-lysine benefits for people with those conditions as well.

Further, l-lysine appears to work with equal amounts of the amino acid arginine to build muscle.

Lysine seems to be very helpful for the treatment of cold sores.

Dosage Recommendations

The dosage recommended for maximum l-lysine benefits is usually 500 mg twice a day. People who want to maximize the benefits can safely take up to twice that amount without adverse effects.

L-lysine is a safe, nontoxic, natural substance when used within recommended amounts.

People with osteoporosis should take l-lysine supplements with calcium for best results in treating this condition.

Those with heart disease or high cholesterol levels should talk to a healthcare provider before taking l-lysine supplements.

Where to Buy Lysine

While lysine is readily available from both offline and online merchants, we recommend iHerb.com, who offers stellar service and super-fast shipping. And, in all the years we’ve been ordering from them, they’ve never screwed anything up, and that’s saying a lot!

As far as brands go, it’s always best to stick with well-known, reputable brands; Now, Jarrow, Doctor’s Best and Solgar are a few examples. We have always been happy with the Now brand products.

Here is where you can learn more about the Now brand 500 mg caps of Lysine (take twice a day for regular dose)

And here is where you can learn more about Now brand 1000 mg caps of Lysine (take twice for double dose and maximum benefit).

Final Comments on L-Lysine Benefits

Hopefully you have found this article helpful – if you did, we would really appreciate it if you shared it on your favorite social media platform (there should be a share button floating around here somewhere).

And of course, if you have any comments or you would like to share about your experiences with the supplement you can do so a little further below, where you can also read about what other people have to say about lysine.

Thanks for reading and all the best!

Author: Paul

Paul Crane is the founder of UltimateFatBurner.com. His passions include supplements, working out, motorcycles, guitars... and of course, his German Shepherd dogs.


  1. Very helpful information. This product was recommended by my 88 year old friend who used when having cold sores on his lip.

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  2. Can the cream lysine also be used on a 7yr old child (lips)

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    • I don’t see why not. I’m not aware of any issues with topical lysine for either adults or children.

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      • Can it be used for losing weight.

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        • Haley, I have not seen any credible to data to suggest it helps with weight loss.

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  3. I’ve been battling cold sore since I was a kid. I tried everything to minimize the length of my outbreaks including valtrex. Nothing works better than l-lysine. I take 1000mg. EVERY DAY! I rarely get outbreaks now and if I do, my cold sores never fully develop. They are gone in two days. When I have an outbreak, I take up to 6gr– 6 x 1000mg. I also have a l-lysine lip balm, you can find in any health food store, but I honestly don’t need it. BEST remedy for cold sores.

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    • Thanks for the feedback!

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  4. I have no insurance. I use to take valtrex 500mg. I’ve had fever blister ever since I was young. Found out comes from having chicken pix. I also had measles at a young age. I’ve had multiple outbreaks, especially when stressed and sick, which is quite often. I’ve even had shingles twice. I’m doamed for life I feel and that stresses me out too! So, If I take 6mg’s of L-Lysine 1000 pet day, I’ll be free of this awful virtus? I realize it will only suppress it! Why can’t there be a cute? Extract the damn viruses from the nerves! I bet there is a cute for everything but CDC, pharmaceuticals and government do not want the public to know! Money maker of illnesses, diseases and virurs, I get it! I hate being plagued! Sucks! And the scarring is such a lovely added bonus! NOT! Help me please! I’m tired!


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    • There may not be a lot of studies done on it helping shingals, but from personal experience it is very effective against it. You need to take massive doses though. Any where from 6000 mg to 10,000mgs. Also this stuff called Monolaurin from cocoanut oil is very effective too. Best to use in combination. God Bless.

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    • Dear Maria : thanks for the information. The tiredness is a side effect of the lysine in the muscles so I am told.Rehydration and stretching exercises are recommended to me by my Chyropractor of all the medical experts.Well from a G.P a gynocologists a natural pathic Dr. and the list goes on. The chyropractor

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  5. Virus. Cure. Apparently I can’t spell on a tiny keyboard through my litte phone. Should have proof read. Where are my glasses. Lol

    But seriously, ignore any typo-misspellings and figure out what I meant to say.

    So frustrating!


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  6. I have been taking L-Lysine for about ten years regularly, 1000mg, 2 x a day. I cant remember the last time I was sick. My immune system is strong because of this product….in my opinion. If I do feel like I am coming down with something, then I take 1000 mg 6 x a day. I didn’t know of all the other benefits of the drug.

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  7. Does l-lysine prevent outbreaks of HSV2?

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  8. I have had shingles and, rarely but, sometimes have a fever blister. IF I feel a little tingle on my lip, I will grab a couple L-Lysine….on an empty stomach. BUT NOW….. I ate some cantaloupe and my lips are VERY STINGY, ITCHY and ROUGH and inside my mouth is raw ! I’m wondering if it’s ok to dissolve a caplet and swish in my mouth. Not sure if it would HELP but, I need something. Does anyone have any ideas ?

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