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Cold sores… painful and painfully embarrassing. Lysine TAKES THEM OUT!

No one, not one living human being enjoys having or looking at a cold sore. If that one person does exist, may God have mercy on their soul. Cold sores are brutal at times, but for a healthy adult Lysine can knock them back pretty quickly especially if they are detected early. If you get cold sores, you will agree they are detectable before the “bloom”.  With a good healthy diet and exercise the virus that causes a cold sore is repressed. In times of great stress, mental or physical, those nasty buggers can surface. Knock them back with 3 to 5 grams of lysine per day in several doses. I was talking to Neil and Ricardo, some friends at work, about cold sores and the use of lysine to beat em back and that inspired me to throw together the following post.  More on this wonderful topic below…

Some main points…

  • Although there’s no cure for cold sores, lysine supplements DO shorten an outbreak in most people. Lysine may also help prevent cold sore outbreaks from coming back.
  • Cold sores are caused by the herpes simplex virus, which lives in the body. Scientists think that lysine prevents the virus from reproducing and causing an outbreak.
  • Certain people, you know who you are — like those who are pregnant or breastfeeding — should avoid taking lysine supplements until research can determine if it’s safe for them. If you are on meds, check with your pharmacist before hitting high doses of lysine. Check with doc if you are looking at this for teen or preteen. Heck, run it past your doctor next visit or a quick call to the office to get their input.

Lysine is an essential amino acid. Amino acids make up proteins in the body. Lysine is known as an “essential” amino acid because the body doesn’t make it naturally. Instead, you get lysine from the foods you eat. Lysine is important for many  bodily functions, like wound healing and the absorption of minerals like calcium.

It is thought that it combats cold sores by blocking the production of another amino acid called arginine. The virus that causes cold sores — herpes simplex virus (HSV) — needs arginine to reproduce.

Lysine may also prevent the absorption of arginine in the intestine. This prevents a person’s body from absorbing it, which slows or prevents the replication and growth of HSV.

Lysine comes as a cream that you can apply directly to a cold sore. It’s also available as an oral supplement and in chewable and powder forms. Most of the existing studies — and all the ones mentioned in this article — have looked at the oral supplement.

Do lysine supplements actually help with cold sores?

Lysine does help prevent and treat cold sores! Some studies show that regularly taking lysine can help prevent outbreaks of cold sores. Others show that it can both prevent cold sores and help them go away sooner.

One study shows that lysine lessens symptoms, reduces healing time, and prevents cold sores from returning. Another small study found that people who took 1,000 mg of oral lysine a day had smaller cold sores than usual during an outbreak. My recommendation for healthy people is 1,000 mg’s every 5 or 6 hours per day til that sucker is GONE!

There’s no cure for HSV, so taking lysine doesn’t get rid of the virus completely. This means that if you get a cold sore, you might still get outbreaks even if you take lysine.

Don’t take extra lysine everyday in perpetuity… as mentioned it blocks arginine from doing its job. Just use it when an outbreak is active.

How fast does lysine work on cold sores?

Fast for most people… More research is needed to know how fast lysine works on cold sores. But a couple studies have tried to answer this question.

One study compared adults who took lysine for an outbreak to those who didn’t use it. Cold sores completely resolved in 3 days for almost half of the people in the lysine group. And nearly all of them saw complete resolution by day 6. But healing time took up to 21 days for people who didn’t use lysine.

A larger study surveyed over 1,500 people with cold sores. Of those who did not take lysine, 90% reported that healing took 6 to 15 days. Among people who did take lysine, 83% said their lesions healed within 5 days.

How much lysine should you take for cold sores?

There is no standardized dosage of lysine. Some studies have used 300 mg of lysine a day, while others have looked at the effects of 3,000 mg of lysine a day. 300 is a total JOKE, don’t waste your time amigo or amiga.

In general, dosages range from 500 mg to 1,000 mg daily by mouth to prevent outbreaks. For active outbreaks, higher doses, like 3,000 to 5,000 mg, may be appropriate for a short period of time.

Some experts suggest that lysine is safe at dosages up to 6,000 mg (6 g) daily. 3 to 5 grams daily for a short period of time for active outbreaks will be fine for healthy adults.

Instructions for over-the-counter lysine cream say that a person can apply it as often as every 2 hours. They keep the area moist which is nice if the outbreak is in the corner of your mouth and keeps splitting open. I hate that! Creams don’t shorten duration.

While lysine is generally safe at the above doses, a few people may experience some not so good side effects.

Common side effects of a lysine supplement may include:

  • Nausea
  • Abdominal pain
  • Cramps
  • Diarrhea
  • Kidney problems
  • Gallstones

Some people may want to avoid it completely because of side effects or safety concerns.

Who should not take lysine?

You should not take lysine if you:

  • Are pregnant or breastfeeding: There isn’t enough research to know if lysine is safe for women who are pregnant or breastfeeding.
  • Take calcium supplements: Lysine increases how much calcium your body absorbs. Too much calcium can lead to muscle pain, weakness, bone pain, and other symptoms.
  • Have gallstones: High doses of lysine can cause gallstones to form. If you have a history of gallstones, say “hell No” to lysine.

People should also avoid lysine if they have a condition that leads to lower levels of arginine, or if they currently have a wound that is healing. This includes people who have:

  • Kidney disease
  • Sickle cell disease
  • Recent surgery
  • Recent trauma or injury

If you are basically healthy try using lysine next outbreak… if you are prone to worry or just want to be safe check with your doctor.


Strictly opinion and not medical advice. Consult your doctor, pharmacist and/or nutritionist before starting/stopping any supplement or exercise program.

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