What is lysine

Lysine or L-lysine is one of nine essential amino acids (building block of protein) in humans required for growth and tissue repair. The human body cannot synthesize lysine, so it is essential in humans and must be obtained from the diet. For all amino acids, including L-lysine, only the L isomer is used in protein synthesis ¹⁾ and can pass across the blood-brain barrier ²⁾. Lysine is supplied by many foods, especially red meats, fish, and dairy products (see Table 1 below). Normal requirements for lysine have been found to be about 8 g per day or 12 mg/kg body weight in adults. Children and infants need more, 44 mg/kg per day for an eleven to-twelve-year old, and 97 mg/kg per day for three-to six-month old ³⁾. Lysine is highly concentrated in muscle compared to most other amino acids. Lysine is high in foods such as wheat germ, cottage cheese and chicken. Of meat products, wild game and pork have the highest concentration of lysine. Fruits and vegetables contain little lysine, except avocados. Normal lysine metabolism is dependent upon many nutrients including niacin, vitamin B6, riboflavin, vitamin C, glutamic acid and iron. Excess arginine antagonizes lysine. Several inborn errors of lysine metabolism are known, such as cystinuria, hyperdibasic aminoaciduria I, lysinuric protein intolerance, propionic acidemia, and tyrosinemia I. Most are marked by mental retardation with occasional diverse symptoms such as absence of secondary sex characteristics, undescended testes, abnormal facial structure, anemia, obesity, enlarged liver and spleen, and eye muscle imbalance.

Lysine deficiency is seen in non-western societies and manifests as protein-energy malnutrition, which has profound and systemic effects on the health of the individual ⁴⁾. This double-blind randomized study in poor peri-urban communities of Accra, Ghana, showed significant benefits of 16 weeks of lysine supplementation on diarrhea morbidity and weight gain in children ⁵⁾. A positive effect of lysine on respiratory disease outcomes was found in men. The results suggest that lysine could be a useful nutritional intervention for decreasing diarrhea morbidity and improving the nutritional status of populations in some developing countries.

Upon digestion from dietary proteins, lysine is transported to the liver from the gut via portal circulation. Its metabolism involves protein synthesis and oxidative catabolism. Lysine catabolism occurs almost exclusively in the liver. It does not undergo transamination ⁶⁾. Lysine is rapidly transported to muscle tissue, and within 5 to 7 hours following ingestion, is highly concentrated in the muscle. Lysine improves calcium assimilation.

Like other amino acids, the metabolism of free lysine follows two principal paths: protein synthesis and oxidative catabolism. Lysine is required for biosynthesis of such substances as carnitine, collagen ⁷⁾ and elastin ⁸⁾. Lysine plays several roles in humans, most importantly proteinogenesis, but also in the crosslinking of collagen polypeptides, uptake of essential mineral nutrients, and in the production of carnitine, which is key in fatty acid metabolism.

A second major role of lysine is in epigenetic regulation by means of histone modification ⁹⁾. There are several types of covalent histone modifications, which commonly involve lysine residues found in the protruding tail of histones. Modifications often include the addition or removal of an acetyl (-CH3CO) forming acetyllysine or reverting to lysine, up to three methyl (‑CH3), ubiquitin or a sumo protein group ¹⁰⁾. The various modifications have downstream effects on gene regulation, in which genes can be activated or repressed.

Lysine has also been implicated to play a key role in other biological processes including; structural proteins of connective tissues, calcium homeostasis, and fatty acid metabolism ¹¹⁾. Lysine has been shown to be involved in the crosslinking between the three helical polypeptides in collagen, resulting in its stability and tensile strength ¹²⁾. This mechanism is akin to the role of lysine in bacterial cell walls, in which lysine (and meso-diaminopimelate) are critical to the formation of crosslinks, and therefore, stability of the cell wall ¹³⁾. Lysine has also been proposed to be involved in calcium intestinal absorption and renal retention, and thus, may play a role in calcium homeostasis ¹⁴⁾. Finally, lysine has been shown to be a precursor for carnitine, which transports fatty acids to the mitochondria, where they can be oxidised for the release of energy ¹⁵⁾. Carnitine is synthesised from trimethyllysine, which is a product of the degradation of certain proteins, as such lysine must first be incorporated into proteins and be methylated prior to being converted to carnitine ¹⁶⁾. It must be noted however, that in mammals the primary source of carnitine is through dietary sources, rather than through lysine conversion ¹⁷⁾.

Due to its importance in several biological processes, a lack of lysine can lead to several disease states including defective connective tissues, impaired fatty acid metabolism, anaemia, and systemic protein-energy deficiency. In contrast, an overabundance of lysine, caused by ineffective catabolism, can cause severe neurological issues.

Lysine is present in many forms of dietary supplements. Lysine is also known as L-2,6-diaminohexanoic acid, Lisina, Lys, Lysine Hydrochloride, Lysine Monohydrochloride, and other names.

L-Lysine is a food additive permitted for direct addition to food for human consumption, as long as 1) the quantity of the substance added to food does not exceed the amount reasonably required to accomplish its intended physical, nutritive, or other technical effect in food, and 2) any substance intended for use in or on food is of appropriate food grade and is prepared and handled as a food ingredient ¹⁸⁾.

Lysine has been used in alternative medicine for the prevention and treatment of herpes infections and cold sores due to herpes simplex viruses (HSV) ¹⁹⁾. Lysine itself does not have antiviral properties, but was believed to act by lowering arginine levels (lysine-arginine antagonism). The mechanism underlying this effect is believed to be based on the virus need for amino acid arginine; lysine competes with arginine for absorption and entry into cells. Lysine inhibits herpes simplex virus (HSV) growth by knocking out arginine. Because herpes simplex virus (HSV) proteins are richer in arginine and poorer in lysine than the cells they infect, lysine supplements have been tried as a treatment. Since the two amino acids are taken up in the intestine, reclaimed in the kidney, and moved into cells by the same amino acid transporters, an abundance of lysine would, in theory, limit the amount of arginine available for viral replication ²⁰⁾. Clinical studies do not provide good evidence for effectiveness as a prophylactic or in the treatment for herpes simplex viruses (HSV) outbreaks ²¹⁾, ²²⁾. In response to product claims that lysine could improve immune responses the HSV, a review by the European Food Safety Authority found no evidence of a cause-effect relationship. The same review, published in 2011, found no evidence to support claims that lysine could lower cholesterol, increase appetite, contribute to protein synthesis in any role other than as an ordinary nutrient, or increase calcium absorption or retention ²³⁾.

Lysine also increases the intestinal absorption of calcium and eliminates its renal excretion, suggesting lysine also may be a useful adjunct in the treatment of osteoporosis. Lysine has been investigated for its effects on increasing muscle mass, lowering glucose, and improving anxiety. Case reports suggest lysine may ameliorate angina pectoris. Lysine acetylsalicylate has been used to treat pain and to detoxify the body after heroin use. Lysine clonixinate has been used for its analgesic properties for the treatment of migraine headaches and other painful conditions. However, limited clinical trials exist for these conditions.

Other uses not proven with research have included canker sores, diabetes, stress, and for athletic performance improvement.

It is not certain whether lysine is effective in treating any medical condition including cold sores due to herpes simplex viruses. Medicinal use of this product has not been approved by the FDA. Lysine should not be used in place of medication prescribed for you by your doctor.

Lysine is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.

Studies of lysine tolerance of human infants have not found adverse effects ²⁴⁾. In one study, six infants (4 to 11 months of age) were given 60 to 1,080 mg of lysine monohydrochloride per 8 ounces of milk in a series of seven incremental doses for 3 to 4 days at each dose. No behavioral effects were observed, nor was there anorexia, diarrhea, or other signs of gastrointestinal upset, and no evidence of cystinuria. Similarly, no adverse effects were reported when 1- to 5-month-old infants were given up to 220 mg/kg body weight of lysine for 15 days ²⁵⁾.

Estimated Average Requirement (EAR) and Recommended Dietary Allowance (RDA) for Lysine for Children Ages 7 Months Through 18 Years

Age and Gender/Amino Acid	Maintenance (mg/kg/day)	Amino Acid Deposition (mg/kg/day)	Total = EAR (mg/kg/day)	RDA (mg/kg/day)
7-12 months, Boys, Girls	31	18	62	89
1-3 years, Boys, Girls	31	8	45	58
4-8 years, Boys, Girls	31	3	37	46
9-13 years, Boys	31	4	37	46
9-13 years, Girls	31	2	35	43
14-18 years, Boys	31	2	35	43
14-18 years, Girls	31	1	32	40

Footnotes:

There are essentially no data with regard to amino acid requirements during pregnancy, so it is generally assumed that indispensable amino acid needs increase in proportion to the increased protein needs during pregnancy. Estimated Average Requirement (EAR) for Pregnancy For all ages: 41 mg/kg/day of lysine.

There are essentially no data with regard to amino acid requirements during lactation, so it is generally assumed that indispensable amino acid needs will increase over the nonlactating needs by the amount of amino acids found in human milk. Estimated Average Requirement (EAR) for Lactation, For all ages: 42 mg/kg/day of lysine

• Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
• Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
• Estimated Average Requirement (EAR): Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
• Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.

[Source ²⁶⁾]

Lysine benefits

Unproven uses and benefits: The most common use of supplemental lysine is for preventing and treating episodes of herpes simplex virus. Lysine has been used in conjunction with calcium to prevent and treat osteoporosis. It has also been used for treating pain, aphthous ulcers, migraine attacks, rheumatoid arthritis, and opiate withdrawal. Many “body-building” formulations contain lysine to aid in muscle repair.

There has been a long discussion that lysine, when administered intravenously or orally, can significantly increase the release of growth hormones ²⁷⁾. This has led to athletes using lysine as a means of promoting muscle growth while training, however, no significant evidence to support this application of lysine has been found to date ²⁸⁾.

Experimental Therapy: A major contributing factor to the loss of mobility in elderly people is the gradual and continuous loss of lean body mass. Elderly (76 +/-1.6 years) women (n = 39) and men (n = 38) were recruited for a double-blinded controlled study. Study participants were randomly assigned to either an isonitrogenous control-supplement (n = 37) or a treatment-supplement consisting of beta-hydroxy-beta-methylbutyrate, L-arginine, and L-lysine (n = 40) for the 1-year study ²⁹⁾. In subjects taking the beta-hydroxy-beta-methylbutyrate, L-arginine, and L-lysine supplement, lean tissue increased over the year of study while in the control group, lean tissue did not change. Consumption of a simple amino acid-related cocktail increased protein turnover and lean tissue in elderly individuals in a year-long study ³⁰⁾.

Although high protein diets result in loss of large amounts of calcium in urine, so does lysine deficiency. Lysine may be an adjunct therapy because it reduces calcium losses in urine. Lysine deficiency also may result in immunodeficiency. Requirements for this amino acid are probably increased by stress. Lysine toxicity has not occurred with oral doses in humans. Lysine dosages are presently too small and may fail to reach the concentrations necessary to prove potential therapeutic applications. Lysine metabolites, amino caproic acid and carnitine have already shown their therapeutic potential. Thirty grams daily of amino caproic acid has been used as an initial daily dose in treating blood clotting disorders, indicating that the proper doses of lysine, its precursor, have yet to be used in medicine. Low lysine levels have been found in patients with Parkinson’s, hypothyroidism, kidney disease, asthma and depression. The exact significance of these levels is unclear, yet lysine therapy can normalize the level and has been associated with improvement of some patients with these conditions. Abnormally elevated hydroxylysines have been found in virtually all chronic degenerative diseases and coumadin therapy. The levels of this stress marker may be improved by high doses of vitamin C. Lysine is particularly useful in therapy for marasmus (wasting) and herpes simplex. Dosing has not been adequately studied, but beneficial clinical effects occur in doses ranging from 100 mg to 4 g a day. Higher doses may also be useful, and toxicity has not been reported in doses as high as 8 g per day.

Lysine for cold sores

Human herpesvirus 1 (HSV type 1) and feline herpesvirus 1 (FHSV type 1) are members of different genera (Simplexvirus and Varicellovirus, respectively), but both belong to the alphaherpesvirinae, a subfamily of the herpesviruses ³¹⁾. Publications claiming a positive effect of lysine supplementation on the treatment or prevention of herpes labialis or genitalis outbreaks in humans were at the basis of research on the efficacy of lysine supplementation in cats infected with FHV-1, both in test tubes ³²⁾ and in cats ³³⁾, ³⁴⁾. In this section we will therefore critically evaluate all clinical studies investigating the efficacy of lysine supplementation in humans infected with human herpes simplex virus 1 (HSV type 1), in a chronological order.

The first publication suggesting a possible role for lysine in the treatment of herpetic lesions was a letter written by Dr. Kagan ³⁵⁾ in 1974. Four years later a first study appeared, under the leadership of Dr. Kagan, in which the authors claimed a beneficial effect of lysine supplementation on the treatment and prevention of herpes simplex outbreaks ³⁶⁾. However, this study by Griffith et al. ³⁷⁾ was not blind (patients knew which medication they received and what the goal of the study was) and there was no control group receiving a placebo. These types of studies are of no scientific value. Indeed, shortly after this study by Griffith et al. ³⁸⁾ was published, a group in Denmark reported that they were unable to replicate these findings. Milman et al. ³⁹⁾ investigated if lysine supplementation was effective to treat herpetic lesions. The results of this randomized, double-blind, placebo-controlled case–control study in which 119 patients were followed for almost a full year showed there was no difference in the recurrence of herpes outbreaks between the group receiving 1000 mg lysine per day (500 mg twice a day) and the group receiving a placebo ⁴⁰⁾. Patients were instructed to start taking their pills (for the duration of about a week) when they first started noticing symptoms. The authors argued that they may have missed an effect of lysine in their study because virus replication may have started before the first symptoms were noticed. But also after 65 patients were given 1000 mg lysine (500 mg twice daily) or a placebo every day for a period of almost half a year in a randomized, double-blind, cross-over study (2 × 12 weeks), no prophylactic effect of lysine on the recurrence of herpes simplex labialis (cold sores on lips) was observed ⁴¹⁾.

Walsh et al. ⁴²⁾ claimed that lysine reduced the number of attacks and shortened healing time. Walsh et al. ⁴³⁾ article, however, describes the results of a questionnaire given to people who bought lysine in a nutrition store. It was uncontrolled and therefore, like other, similar reports ⁴⁴⁾, results are not reliable. These papers cannot be used to help determine the efficacy of lysine on the prevention or treatment of herpetic lesions. Despite the poor quality of these articles, some authors, unfortunately, still cite these publications, sometimes selectively, using their untrustworthy results to support their claims.

A small (n = 20), but well controlled (randomized, double-blind, placebo-controlled case–control) study ⁴⁵⁾ in which the effect of 1200 mg lysine per day on recurrence, duration and severity of herpetic lesions was investigated for 4–5 months, confirmed the negative findings of Milman et al. ⁴⁶⁾. A study performed by McCune et al. ⁴⁷⁾ had a size (n = 20) and design somewhat similar (double-blind, placebo-controlled cross-over) to the study performed by DiGiovanna et al. ⁴⁸⁾. The authors did not find a positive effect of lysine on healing rate, but did describe that oral ingestion of 1250 mg lysine daily for a period of 24 weeks lowered the number of recurrences when lysine was taken as compared to when the patients took a placebo ⁴⁹⁾.

Thein and colleagues ⁵⁰⁾ were the first to study if there was a correlation between both plasma lysine and arginine levels, and the number of herpetic lesions. In this double-blind, placebo-controlled cross-over study (n = 26) that lasted for 1 year, it was attempted to control for dietary factors to determine efficacy of lysine supplementation, as was also suggested by Algert et al. ⁵¹⁾. In all studies, dietary changes were suggested or recommended, but diet has never been well controlled for. Thein et al. ⁵²⁾ found a reduction in the number of lesions, but it was independent of the treatment type (1 g lysine/day or placebo). It was hypothesized that lysine may be effective only when a certain minimum level of lysine in the plasma is reached. Algert’s paper ⁵³⁾ described that there is no difference in dietary intake for lysine and arginine between a group of patients with initial or recurrent herpes genitalis infections and a control group, although it is not clear how many persons in the control group were latently infected. In addition, the authors mention that the American diet is rich in lysine (6–10 g per day), which makes deficiencies rare since the recommended intake is about 2 g per day ⁵⁴⁾.

In two randomized, double-blind, placebo-controlled case–control studies, Simon et al. ⁵⁵⁾ (1 g/day for 3 months, n = 31) and Griffith et al. ⁵⁶⁾ (3 g/day for 6 months, n = 52) claimed positive results of lysine supplementation. However, both studies compared the number of herpetic outbreaks with self-reported predicted recurrence rates based on the patient’s history, thereby introducing unnecessary bias ⁵⁷⁾. When the number of outbreaks was compared between the group that received 3000 mg lysine daily and the group receiving a placebo, no difference was seen ⁵⁸⁾. No new study results on this subject were published after this publication in 1987 ⁵⁹⁾.

In addition to the small sample sizes, poor study designs and improper analyses, scientists have other concerns that need to be addressed. Several of the researchers who published about lysine and herpes simplex virus-1 held a position at a pharmaceutical company manufacturing lysine supplements (Lilly and GNC), and therefore there was a conflict of interest. All their publications described a positive effect of lysine supplementation. Furthermore, there may be a publication bias, since journals are less willing to reports negative findings (e.g. a study describing the absence of an effect) than studies with statistically significant results ⁶⁰⁾. There may have been other research groups that were unable to demonstrate the efficacy of lysine, whose results were not published.

Lysine supplementation is not effective for the treatment or prevention of herpetic lesions in humans infected with human herpesvirus 1 ⁶¹⁾. Futhermore, 2015 Cochrane Review ⁶²⁾ found based on available evidence no preventative effects of lysine, LongoVital® supplementation, gamma globulin, herpes virus vaccine, and yellow fever vaccine for cold sores.

Lysine supplement side effects

Gastrointestinal side effects, such as diarrhea, nausea, and abdominal pain, have been reported with lysine ingestion. A case report described the development of Fanconi syndrome and tubulointerstitial nephritis associated with lysine supplementation taken over a 5-year period.

Acute intake of high levels of lysine interferes with dietary protein metabolism and competes with the transport of arginine, suggesting that adverse effects from high levels of lysine are more likely to occur if protein intake or dietary arginine intake is low ⁶³⁾.

Patients with hypercholesterolemia should be aware that supplemental lysine has been linked to increased cholesterol levels in animal studies. However, other studies have shown lysine can also decrease cholesterol levels ⁶⁴⁾. Increased liver total lipids, triacylglycerol, and cholesterol concentrations were seen in rats fed 5% L-lysine and 15% casein for 2 weeks, an effect that can be reversed by feeding arginine ⁶⁵⁾.

Lysine supplementation is contraindicated in patients with hyperlysinemia/hyperlysinuria. Patients with liver and kidney disease should avoid supplementation with lysine ⁶⁶⁾. If use is warranted, patients should consult a health care provider ⁶⁷⁾.

Drug interactions

Concomitant use of calcium supplements with lysine may be associated with increased absorption and reduced elimination of calcium. Aminoglycoside toxicity may be enhanced in patients taking lysine supplementation.

Lysine rich foods

Table 1. Foods high in lysine (ordered from high to low)

Description	Lysine (g) Value Per 100 gram
Whale, beluga, meat, dried (Alaska Native)	6.31
Egg, white, dried, stabilized, glucose reduced	5.9
Fish, cod, Atlantic, dried and salted	5.77
Egg, white, dried	5.51
Soy protein isolate	5.33
Soy protein isolate, potassium type	5.33
Egg, white, dried, powder, stabilized, glucose reduced	5.08
Egg, white, dried, flakes, stabilized, glucose reduced	4.74
Soy protein concentrate, produced by alcohol extraction	3.93
Soy protein concentrate, produced by acid wash	3.93
Cheese, parmesan, shredded	3.84
Beef, round, top round roast, boneless, separable lean only, trimmed to 0″ fat, select, cooked, roasted	3.61
Beef, round, eye of round roast, boneless, separable lean only, trimmed to 0″ fat, select, cooked, roasted	3.58
Beverages, Protein powder soy based	3.55
Beef, loin, top sirloin filet, boneless, separable lean only, trimmed to 0″ fat, select, cooked, grilled	3.55
Beef, plate steak, boneless, inside skirt, separable lean only, trimmed to 0″ fat, select, cooked, grilled	3.54
Pork, cured, bacon, cooked, microwaved	3.47
Gelatins, dry powder, unsweetened	3.46
Beef, round, top round steak, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, grilled	3.44
Beef, top loin filet, boneless, separable lean only, trimmed to 1/8″ fat, select, cooked, grilled	3.44
Beef, loin, top loin steak, boneless, lip-on, separable lean only, trimmed to 1/8″ fat, select, cooked, grilled	3.42
Beef, loin, top loin steak, boneless, lip off, separable lean only, trimmed to 0″ fat, select, cooked, grilled	3.41
Beef, round, eye of round steak, boneless, separable lean only, trimmed to 0″ fat, select, cooked, grilled	3.4
Beef, loin, top sirloin petite roast, boneless, separable lean only, trimmed to 0″ fat, select, cooked, roasted	3.39
Beef, rib, back ribs, bone-in, separable lean only, trimmed to 0″ fat, select, cooked, braised	3.38
Beef, rib eye steak, boneless, lip-on, separable lean only, trimmed to 1/8″ fat, select, cooked, grilled	3.34
Beef, rib eye steak, boneless, lip off, separable lean only, trimmed to 0″ fat, select, cooked, grilled	3.34
Egg, whole, dried	3.34
Beef, round, top round steak, boneless, separable lean only, trimmed to 0″ fat, choice, cooked, grilled	3.32
Beef, rib eye roast, boneless, lip-on, separable lean only, trimmed to 1/8″ fat, select, cooked, roasted	3.31
Cheese, parmesan, hard	3.31
Beef, plate steak, boneless, outside skirt, separable lean only, trimmed to 0″ fat, select, cooked, grilled	3.31
Beef, top loin petite roast, boneless, separable lean only, trimmed to 1/8″ fat, select, cooked, roasted	3.29
Leavening agents, yeast, baker’s, active dry	3.28
Beef, ribeye petite roast, boneless, separable lean only, trimmed to 0″ fat, select, cooked, roasted	3.27
Beef, loin, top sirloin cap steak, boneless, separable lean only, trimmed to 1/8″ fat, select, cooked, grilled	3.27
Beef, round, top round roast, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, roasted	3.26
Egg, whole, dried, stabilized, glucose reduced	3.25
Game meat, beaver, cooked, roasted	3.24
Beef, loin, tenderloin steak, boneless, separable lean only, trimmed to 0″ fat, select, cooked, grilled	3.24
Beef, round, eye of round roast, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, roasted	3.23
Beef, rib eye steak, bone-in, lip-on, separable lean only, trimmed to 1/8″ fat, select, cooked, grilled	3.23
Beef, loin, top sirloin filet, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, grilled	3.21
Beef, round, top round steak, boneless, separable lean and fat, trimmed to 0″ fat, select, cooked, grilled	3.21
Beef, ribeye filet, boneless, separable lean only, trimmed to 0″ fat, select, cooked, grilled	3.19
Beef, loin, tenderloin roast, separable lean only, boneless, trimmed to 0″ fat, select, cooked, roasted	3.18
Tofu, dried-frozen (koyadofu)	3.16
Tofu, dried-frozen (koyadofu), prepared with calcium sulfate	3.16
Beef, short loin, t-bone steak, bone-in, separable lean only, trimmed to 1/8″ fat, select, cooked, grilled	3.15
Beef, plate steak, boneless, inside skirt, separable lean only, trimmed to 0″ fat, all grades, cooked, grilled	3.15
Beef, short loin, porterhouse steak, separable lean only, trimmed to 1/8″ fat, select, cooked, grilled	3.14
Lamb, shoulder, arm, separable lean only, trimmed to 1/4″ fat, choice, cooked, braised	3.14
Beef, round, eye of round steak, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, grilled	3.14
Game meat, bison, chuck, shoulder clod, separable lean only, cooked, braised	3.13
Beef, round, top round steak, boneless, separable lean only, trimmed to 0″ fat, select, cooked, grilled	3.13
Soy flour, defatted	3.13
Beef, round, top round steak, boneless, separable lean and fat, trimmed to 0″ fat, all grades, cooked, grilled	3.13
Beef, rib eye roast, bone-in, lip-on, separable lean only, trimmed to 1/8″ fat, select, cooked, roasted	3.12
Parsley, freeze-dried	3.12
Turkey, retail parts, wing, meat only, cooked, roasted	3.11
Beef, round, top round steak, boneless, separable lean and fat, trimmed to 0″ fat, choice, cooked, grilled	3.11
Beef, loin, top loin steak, boneless, lip off, separable lean only, trimmed to 0″ fat, all grades, cooked, grilled	3.1
CRACKER BARREL, grilled sirloin steak	3.1
Chicken, broiler or fryers, breast, skinless, boneless, meat only, cooked, braised	3.08
Beef, top loin filet, boneless, separable lean only, trimmed to 1/8″ fat, all grades, cooked, grilled	3.08
Pork, cured, bacon, cooked, broiled, pan-fried or roasted, reduced sodium	3.07
Beef, round, top round roast, boneless, separable lean only, trimmed to 0″ fat, choice, cooked, roasted	3.07
Beef, round, top round roast, boneless, separable lean and fat, trimmed to 0″ fat, select, cooked, roasted	3.06
Beef, loin, top sirloin petite roast, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, roasted	3.06
Beef, loin, top loin steak, boneless, lip-on, separable lean only, trimmed to 1/8″ fat, all grades, cooked, grilled	3.06
Turkey, retail parts, breast, meat only, cooked, roasted	3.04
Pork, cured, bacon, pre-sliced, cooked, pan-fried	3.04
Beef, round, eye of round roast, boneless, separable lean and fat, trimmed to 0″ fat, select, cooked, roasted	3.04
Beef, round, eye of round roast, boneless, separable lean only, trimmed to 0″ fat, choice, cooked, roasted	3.04
Beef, loin, top sirloin filet, boneless, separable lean only, trimmed to 0″ fat, choice, cooked, grilled	3.04
Seaweed, spirulina, dried	3.02
Veal, leg (top round), separable lean only, cooked, braised	3.02
Beef, ribeye filet, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, grilled	3.02
Lamb, Australian, imported, fresh, shoulder, arm, separable lean only, trimmed to 1/8″ fat, cooked, braised	3.02
Beef, chuck, mock tender steak, boneless, separable lean only, trimmed to 0″ fat, choice, cooked, braised	3.02
Beef, round, top round, separable lean and fat, trimmed to 0″ fat, all grades, cooked, braised	3.01
Lamb, New Zealand, imported, frozen, shoulder, whole (arm and blade), separable lean only, cooked, braised	3.01
Beef, round, top round, separable lean only, trimmed to 0″ fat, choice, cooked, braised	3.01
Beef, round, top round, separable lean only, trimmed to 0″ fat, select, cooked, braised	3.01
Mutton, cooked, roasted (Navajo)	3
Beef, loin, tenderloin steak, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, grilled	3
Beef, chuck, mock tender steak, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, braised	3
Soy meal, defatted, raw	2.99
Beef, round, eye of round steak, boneless, separable lean only, trimmed to 0″ fat, choice, cooked, grilled	2.98
Beef, rib, back ribs, bone-in, separable lean only, trimmed to 0″ fat, all grades, cooked, braised	2.98
Veal, leg (top round), separable lean and fat, cooked, braised	2.98
Beef, composite of trimmed retail cuts, separable lean only, trimmed to 0″ fat, select, cooked	2.98
Beef, top loin petite roast, boneless, separable lean only, trimmed to 1/8″ fat, all grades, cooked, roasted	2.98
Lamb, cubed for stew or kabob (leg and shoulder), separable lean only, trimmed to 1/4″ fat, cooked, braised	2.98
Beef, plate steak, boneless, inside skirt, separable lean and fat, trimmed to 0″ fat, select, cooked, grilled	2.97
Beef, loin, top sirloin cap steak, boneless, separable lean only, trimmed to 1/8″ fat, all grades, cooked, grilled	2.97
Beef, chuck, mock tender steak, boneless, separable lean only, trimmed to 0″ fat, select, cooked, braised	2.96
Beef, rib eye roast, boneless, lip-on, separable lean only, trimmed to 1/8″ fat, all grades, cooked, roasted	2.96
Pork, cured, bacon, cooked, baked	2.96
Chicken, broilers or fryers, rotisserie, original seasoning, breast, meat and skin, cooked	2.96
Beef, round, top round, separable lean and fat, trimmed to 0″ fat, choice, cooked, braised	2.96
Beef, round, top round, separable lean and fat, trimmed to 0″ fat, select, cooked, braised	2.96
Beef, short loin, porterhouse steak, separable lean only, trimmed to 1/8″ fat, all grades, cooked, grilled	2.96
Beef, ribeye petite roast, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, roasted	2.96
Beef, round, top round roast, boneless, separable lean and fat, trimmed to 0″ fat, all grades, cooked, roasted	2.96
Beef, rib eye steak, boneless, lip off, separable lean only, trimmed to 0″ fat, all grades, cooked, grilled	2.96
Beef, round, bottom round, steak, separable lean only, trimmed to 0″ fat, select, cooked, braised	2.95
Turkey, retail parts, drumstick, meat only, cooked, roasted	2.95
Beef, plate steak, boneless, inside skirt, separable lean only, trimmed to 0″ fat, choice, cooked, grilled	2.95
Veal, shoulder, arm, separable lean only, cooked, braised	2.94
Cheese, romano	2.94
Beef, rib eye steak, boneless, lip-on, separable lean only, trimmed to 1/8″ fat, all grades, cooked, grilled	2.94
Chicken, broiler or fryers, breast, skinless, boneless, meat only, cooked, grilled	2.94
Beef, chuck, arm pot roast, separable lean only, trimmed to 1/8″ fat, choice, cooked, braised	2.93
Mollusks, whelk, unspecified, cooked, moist heat	2.93
Beef, chuck, arm pot roast, separable lean only, trimmed to 1/8″ fat, all grades, cooked, braised	2.93
Beef, chuck, arm pot roast, separable lean only, trimmed to 1/8″ fat, select, cooked, braised	2.92
Beef, chuck for stew, separable lean and fat, choice, cooked, braised	2.92
Beef, chuck for stew, separable lean and fat, all grades, cooked, braised	2.92
Beef, ribeye cap steak, boneless, separable lean only, trimmed to 0″ fat, select, cooked, grilled	2.92
Game meat, deer, shoulder clod, separable lean only, cooked, braised	2.91
Beef, round, top round roast, boneless, separable lean and fat, trimmed to 0″ fat, choice, cooked, roasted	2.91
Beef, round, eye of round steak, boneless, separable lean and fat, trimmed to 0″ fat, select, cooked, grilled	2.91
Beef, round, bottom round, steak, separable lean only, trimmed to 1/8″ fat, select, cooked, braised	2.91
Beef, composite of trimmed retail cuts, separable lean only, trimmed to 0″ fat, all grades, cooked	2.91
Lamb, New Zealand, imported, fore-shank, separable lean only, cooked, braised	2.91
Beef, plate steak, boneless, outside skirt, separable lean only, trimmed to 0″ fat, all grades, cooked, grilled	2.91
Chicken, broilers or fryers, rotisserie, original seasoning, breast, meat only, cooked	2.91
Beef, round, bottom round, steak, separable lean and fat, trimmed to 0″ fat, select, cooked, braised	2.91
Beef, round, eye of round roast, boneless, separable lean and fat, trimmed to 0″ fat, all grades, cooked, roasted	2.91
Beef, chuck for stew, separable lean and fat, select, cooked, braised	2.9
Beef, round, bottom round, steak, separable lean only, trimmed to 1/8″ fat, all grades, cooked, braised	2.9
Beef, loin, top loin steak, boneless, lip off, separable lean and fat, trimmed to 0″ fat, select, cooked, grilled	2.9
Lamb, shoulder, whole (arm and blade), separable lean only, trimmed to 1/4″ fat, choice, cooked, braised	2.9
Beef, round, bottom round, steak, separable lean only, trimmed to 1/8″ fat, choice, cooked, braised	2.89
Game meat, rabbit, wild, cooked, stewed	2.89
Beef, top loin filet, boneless, separable lean only, trimmed to 1/8″ fat, choice, cooked, grilled	2.89
Beef, loin, tenderloin roast, boneless, separable lean only, trimmed to 0″ fat, all grades, cooked, roasted	2.89
Beef, round, eye of round roast, boneless, separable lean and fat, trimmed to 0″ fat, choice, cooked, roasted	2.89
Beef, loin, top sirloin petite roast, boneless, separable lean only, trimmed to 0″ fat, choice, cooked, roasted	2.89
Beef, chuck eye Country-Style ribs, boneless, separable lean only, trimmed to 0″ fat, select, cooked, braised	2.89
Beef, loin, tenderloin steak, boneless, separable lean only, trimmed to 0″ fat, choice, cooked, grilled	2.89
Beef, loin, top loin steak, boneless, lip off, separable lean only, trimmed to 0″ fat, choice, cooked, grilled	2.88
Turkey, retail parts, breast, meat and skin, cooked, roasted	2.88
Beef, chuck, under blade steak, boneless, separable lean only, trimmed to 0″ fat, select, cooked, braised	2.88
Beef, rib eye steak, bone-in, lip-on, separable lean only, trimmed to 1/8″ fat, all grades, cooked, grilled	2.88
Veal, cubed for stew (leg and shoulder), separable lean only, cooked, braised	2.88
Beef, round, top round, separable lean and fat, trimmed to 1/8″ fat, select, cooked, braised	2.88
Beef, round, bottom round, steak, separable lean only, trimmed to 0″ fat, all grades, cooked, braised	2.87
Milk, dry, nonfat, regular, without added vitamin A and vitamin D	2.87

[Source ⁶⁸⁾]

Table 2. Plants with the highest amount of Lysine

Genus species	Common name(s)	Concentration	Area of plant
Cucurbita foetidissima HBK.	Buffalo Gourd	10,130 – 33,000 ppm	Seed
Nasturtium officinale R. BR.	Berro, Watercress	1,340 – 26,800 ppm	Herb
Glycine max (L.) MERR.	Soybean	24,290 – 26,560 ppm	Seed
Ceratonia siliqua L.	Carob, Locust Bean, St.John’s-Bread	26,320 ppm	Seed
Phaseolus vulgaris subsp. var. vulgaris	Black Bean, Dwarf Bean, Field Bean, Flageolet Bean, French Bean, Garden Bean, Green Bean, Haricot, Haricot Bean, Haricot Vert, Kidney Bean, Navy Bean, Pop Bean, Popping Bean, Snap Bean, String Bean, Wax Bean	2,390 – 25,700 ppm	Sprout Seedling
Moringa oleifera LAM.	Ben Nut, Benzolive Tree, Drumstick Tree, Horseradish Tree, Jacinto (Sp.), Moringa, West Indian Ben	5,370 – 25,165 ppm	Shoot
Lens culinaris MEDIK.	Lentil	7,120 – 23,735 ppm	Sprout Seedling
Psophocarpus tetragonolobus (L.) DC.	Asparagus Pea, Goa Bean, Winged Bean	21,360 – 23,304 ppm	Seed
Chenopodium album L.	Lambsquarter	3,540 – 22,550 ppm	Seed
Lens culinaris MEDIK.	Lentil	19,570 – 22,035 ppm	Seed
Lupinus albus L.	White Lupine	19,330 – 21,585 ppm	Seed
Nigella sativa L.	Black Caraway, Black Cumin, Fennel-Flower, Nutmeg-Flower, Roman Coriander	16,200 – 20,700 ppm	Seed
Spinacia oleracea L.	Spinach	1,740 – 20,664 ppm	Plant
Mucuna pruriens (L.) DC.	Cowage, Velvetbean	9,700 – 20,564 ppm	Seed
Acacia farnesiana (L.) WILLD.	Cassie, Huisache, Opopanax, Popinac, Sweet Acacia	3,760 – 20,170 ppm	Leaf
Pisum sativum L.	Pea	2,020 – 19,980 ppm	Fruit
Cucurbita pepo L.	Pumpkin	18,330 – 19,693 ppm	Seed
Vicia faba L.	Broadbean, Faba Bean, Habas	3,660 – 19,265 ppm	Seed
Brassica chinensis L.	Bok-Choy, Celery Cabbage, Celery Mustard, Chinese Cabbage, Chinese Mustard, Chinese White Cabbage, Pak-Choi	890 – 19,019 ppm	Leaf
Phaseolus lunatus L.	Butter Bean, Lima Bean	4,520 – 19,010 ppm	Seed
Petroselinum crispum (MILLER) NYMAN EX A. W. HILLL	Parsley	2,190 – 18,724 ppm	Plant
Asparagus officinalis L.	Asparagus	1,450 – 18,710 ppm	Shoot
Trigonella foenum-graecum L.	Alholva (Sp.), Bockshornklee (Ger.), Fenugreek, Greek Clover, Greek Hay	15,310 – 18,525 ppm	Seed
Vigna radiata (L.) WILCZEK	Green Gram, Mungbean	16,640 – 18,296 ppm	Seed
Lablab purpureus (L.) SWEET	Bonavist Bean, Hyacinth Bean, Lablab Bean	190 – 18,000 ppm	Seed
Triticum aestivum L.	Wheat	15,000 – 18,000 ppm	Plant
Vigna unguiculata subsp. sesquipedalis (L.) VERDC.	Asparagus Bean, Pea Bean, Yardlong Bean	16,460 – 17,975 ppm	Seed
Corchorus olitorius L.	Jew’s Mallow, Mulukiya, Nalta Jute	1,540 – 17,825 ppm	Leaf
Vigna radiata (L.) WILCZEK	Green Gram, Mungbean	1,666 – 17,437 ppm	Sprout Seedling
Vigna angularis (WILLD.) OHWI & H. OHASHI	Adzuki Bean	14,970 – 17,294 ppm	Seed

[Source ⁶⁹⁾]