L-Lysine: Overview

Lysine is one of numerous amino acids that the body needs for growth and tissue repair.  It is classified as one of the nine "essential" amino acids because you need to get it from outside sources such as foods or supplements – your body can't make it on its own.

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As an amino acid, it is found in a host of foods and is not normally deficient in the diet.  Many foods supply lysine, but the richest sources by far include red meats, fish, and dairy products (milk, eggs, cheese).  Vegetables, on the other hand, are generally a poor source of lysine, with the exception of legumes (beans, peas, lentils).

Of all the amino acids, lysine is the most sensitive to the effects of food processing, such as dry heat.  The amount of protein available in legumes and other sources of lysine can be significantly reduced if they have been toasted or roasted.

While many people satisfy their need for lysine through dietary sources, supplements are now popular for treating and preventing specific ailments as well.

Supplements come in various forms: tablet, powder, liquid, and capsule.

Function; Why it is Recommended

Like all amino acids, lysine functions as a building block for proteins.  It is also a key player in the production of various enzymes, hormones, and disease-fighting antibodies.  It is necessary for proper growth and helps form collagen which comprises bone cartilage and connective tissues.

Researchers are exploring the value of lysine supplementation and the consumption of lysine-rich foods for lowering cholesterol, improving athletic performance, and enhancing recovery after surgery.  Because Lysine helps repair tissue, it is a good supplement for anyone recovering from surgery and injuries.

Lysine is helpful in lowering triglycerides and as an anti-aging factor.  It is involved in the structural repair of damaged blood vessels.

Recently it has been shown that L-Lysine can inhibit the growth of the herpes virus.  Herpes virus requires many proteins with the amino acid arginine, and lysine competes directly with arginine in many of these processes.  This competition is thought to slow down the growth of the herpes virus.  While high doses (500-1500 mg/day) are beneficial during the suppression of viral growth, lesser amounts should be taken, if taking on an on going basis to prevent an amino acid imbalance problem.


At the time of writing there is no official RDA for lysine.  It is estimated, however, that the daily requirement for an adult is approximately 12mg per kilogram (2.2lb) of body weight.

Side-Effects; Counter-Indicators and Warnings

Side-effects are rare with lysine supplements, although a few cases of abdominal cramps and diarrhea have been reported with very high doses (more than 10gm per day).

In very large doses (10 to 30gm per day), lysine increases the toxicity of aminoglycoside antibiotics, such as gentamicin, neomycin, and streptomycin.

References & Further Information

A comprehensive list of foods and their lysine/arginine content can be found here.

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L-Lysine can help with the following:


Hypertension (High Blood Pressure)

Lysine has a beneficial effect on high blood pressure.

Environment / Toxicity

Heavy Metal Toxicity

Lysine has a beneficial effect on lead toxicity.


Herpes Simplex Type I

The amino acid lysine often controls herpes.  Supplementation with free-form lysine has shown to be beneficial in controlling herpes along with a diet high in lysine and low in arginine.  It has been found that foods high in I-Arginine may cause herpes outbreaks.  Increased levels of lysine over arginine suppress viral replication and inhibit cytopathogenicity of herpes simplex virus.  L-Lysine appears to be an effective agent for reduction of the occurrence, severity and healing time for recurrent HSV infection.  Several doctors have reported that if lysine use reduces herpes outbreaks, an immunological imbalance is present.  Treatments aimed at immune system improvement have been effective in eliminating or reducing recurrence.

Foods high in lysine and low in arginine include most fruits and vegetables, fish, chicken, beef, lamb, milk, cheese, beans, brewer's yeast and mung bean sprouts.  Gelatin, chocolate, carob, coconut, oats, whole-wheat and white flour, peanuts, soybeans, and wheat germ have more arginine than lysine and should thus be avoided.  To quote one study, "The amount of lysine required to control herpes varied from case to case but a typical dose to maintain remission was 500mg daily and active herpes required 1 to 6gm between meals to induce healing."

Drs. Kagan, Griffith and Norins at the UCLA School of Medicine found of 45 patients receiving L-Lysine for herpes, only two failed to respond (a 96% success rate).  The patients were receiving about 1500mg L-Lysine daily.

Lysine supplements (as opposed to foods high in this nutrient) can play an important role in staving off and reducing the severity of herpes-related cold sores.  Results of a six-month trial involving more than 50 people indicate that lysine is far more effective than a placebo in preventing cold sores.  Participants given a placebo had more than twice as many such infections as those taking lysine.  Moreover, the herpes sores that did develop in the lysine group tended to be milder, and to heal faster, than the outbreaks in the placebo group.  Lysine supplements may even prevent HSV outbreaks in chronic sufferers.  General advice is to take 1,000mg L-lysine three times a day with meals for flare-ups.  If you are subject to recurrent outbreaks of cold sores, continue on a maintenance dosage of 1,000mg per day.

Shingles (Herpes Zoster)

Lysine can speed the healing of shingles lesions.  Painful shingles blisters are caused by a reactivation of varicella-zoster virus, an infection that started out as an attack of chickenpox.  Herpes zoster is closely related to herpes simplex, however, and lysine appears to have a similar role to play in treating an eruption of shingles.  Most physicians who recommend lysine will combine this therapy with conventional antiviral medications such as acyclovir or valacyclovir.  Recommendation: Take 1,000mg L-lysine three times a day with meals during flare-ups.  Reduce the dose to 500mg three times a day for one week after healing.

Canker Sores (Aphthous Ulcers)

Some nutritionally-oriented physicians and dentists recommend taking lysine during an outbreak of canker sores to speed healing.  However, there have been almost no clinical trials using lysine as a remedy for canker sores.  Take 1,000mg L-lysine three times a day with meals while a canker sore is present.  Reduce the dose to 500mg three times a day for one week following healing.  Take 1,000mg L-lysine three times a day with meals while a canker sore is present.  Reduce the dose to 500mg three times a day for one week following healing.

Sexually-Transmitted Diseases

Herpes Simplex Type II

Researchers recently discovered that, in order to replicate, the herpes virus needs arginine, another common amino acidLysine competes with arginine for absorption and entry into tissue cells.  And when lysine is present, it inhibits the growth of HSV by knocking out arginine.

This makes a diet high in lysine and low in arginine a useful tool in managing HSV infections.  In one study, participants consumed large amounts of lysine (about 1gm three times daily) while restricting food sources of arginine.  A significant number of participants (74%) noticed an improvement in their HSV infections and a decrease in the number of outbreaks.

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