The AtlasAmino acidsPositively charged
LysineLys · K
The limiting amino acid in the world’s grain, the anchor point for collagen’s cross-links and histone marks, and the supplement most often sold for cold sores.
Molecule · Lys · 10 heavy atoms
Lysine
C6H14N2O2146.19 g/mol
The limiting amino acid in the world’s grain, the anchor point for collagen’s cross-links and histone marks, and the supplement most often sold for cold sores.
Built fromthe charted ones open their own entry
- Codes
- Lys · K
- Formula
- C6H14N2O2
- Molar mass
- 146.19 g/mol
- Systematic name
- (2S)-2,6-diaminohexanoic acid
- Side chain
- 4-Aminobutyl: four CH₂ groups ending in an amine; positively charged at the pH of blood.
- Class
- Positively charged
- In the diet
- Essential
- Carbon skeleton
- Ketogenic
- pKa
- α-COOH 2.18 · α-NH3+ 8.95 · side chain 10.53
- Isoelectric point
- pH 9.74
- Hydropathy
- -3.9 (Kyte–Doolittle)
- Codons
AAAAAG- Main transporters
- SLC7A7 (y⁺LAT1, with CD98), SLC3A1, SLC7A9 (rBAT, b⁰,⁺AT)
pKa and isoelectric point: Nelson and Cox, Lehninger Principles of Biochemistry, table of amino acid properties (free amino acid, 25 °C). Hydropathy: Kyte and Doolittle, J Mol Biol 1982. Essentiality: Reeds, J Nutr 2000. Formula and mass computed from the structure.
In brief
What it is
An essential amino acid with a long, flexible four-carbon side chain that ends in a positively charged amino group. It cannot be made in the body 1.
Why it matters
It is the amino acid cereal proteins run out of first, which is why grains and legumes together feed people better than either alone 2,3. In the body its side-chain amine is the place where collagen is cross-linked, histones are marked, and proteins are tagged for destruction 4,5,6.
Where it runs short
In diets built on a single cereal, lysine is what runs short; requirement studies in Indian men put the need at about 30 mg/kg a day, more than double the 1985 estimate, and higher still in undernourished men 7,8.
Where it turns
Lysine is well tolerated as a supplement: a review of 71 studies set a provisional no-observed-adverse-effect level of 6 g a day, with stomach upset the usual complaint above it 9. The serious problems are inherited blocks in its breakdown 10.
In the diet it is the shortfall that matters; in medicine it is the breakdown.
The molecule
Lysine’s side chain is a straight run of four carbons ending in an amino group. That amine has a pKa of about 10.5, so at the pH of blood it is almost always protonated and positive; the long, flexible chain lets it reach out of a protein’s surface into water.
Because that amine is reactive and exposed, it is where much of the cell’s chemistry happens to a protein after it is made. Histone tails are acetylated and methylated on lysines to switch genes on and off 5; ubiquitin is joined to target proteins through an isopeptide bond to a lysine, marking them for destruction or redirecting them 6; and in 2009 mass spectrometry found acetylation on 3,600 lysines in 1,750 proteins, spread across almost every cellular process 11.
That list is still growing, and the newest entries are written by metabolism rather than by signaling. Lysine pyruvylation — pyruvate attached to a lysine side chain — has now been characterized systematically: 88 sites across mammalian cells, added by the acetyltransferases HAT1 and p300, removed by SIRT3, and rising and falling with glycolytic flux and pyruvate concentration 12. It joins lactylation on the same principle. A cell's metabolic state is physically written onto its lysines, which means the modifications on this list are not only instructions but also a record.
Move across the chart to read the charge at any pH.
Computed from its pKa values (α-carboxyl 2.18, α-amino 8.95, side chain 10.53) by the Henderson–Hasselbalch equation, for the free amino acid in water at 25 °C. Inside a folded protein the same groups can shift by a unit or more. The faint lines are the other amino acids.
Kyte–Doolittle hydropathy index: positive values avoid water and tend to be buried inside a folded protein, negative values sit on its surface. Each letter is an amino acid; choose one to open it.
| 1st ↓ 2nd → | U | C | A | G | 3rd |
|---|---|---|---|---|---|
| U | UUUPhe | UCUSer | UAUTyr | UGUCys | U |
| UUCPhe | UCCSer | UACTyr | UGCCys | C | |
| UUALeu | UCASer | UAAStop | UGAStop | A | |
| UUGLeu | UCGSer | UAGStop | UGGTrp | G | |
| C | CUULeu | CCUPro | CAUHis | CGUArg | U |
| CUCLeu | CCCPro | CACHis | CGCArg | C | |
| CUALeu | CCAPro | CAAGln | CGAArg | A | |
| CUGLeu | CCGPro | CAGGln | CGGArg | G | |
| A | AUUIle | ACUThr | AAUAsn | AGUSer | U |
| AUCIle | ACCThr | AACAsn | AGCSer | C | |
| AUAIle | ACAThr | AAALys | AGAArg | A | |
| AUGMet | ACGThr | AAGLys | AGGArg | G | |
| G | GUUVal | GCUAla | GAUAsp | GGUGly | U |
| GUCVal | GCCAla | GACAsp | GGCGly | C | |
| GUAVal | GCAAla | GAAGlu | GGAGly | A | |
| GUGVal | GCGAla | GAGGlu | GGGGly | G |
Where it comes from
Lysine is essential. The adult requirement is 30 mg per kilogram a day 1, set after tracer studies showed the 1985 figure of 12 mg/kg was far too low: well-nourished Indian men needed about 31 mg/kg, and chronically undernourished men about 44 7,8. That figure is now under pressure from both ends. The evidence base behind every reference value of this kind was audited in 2025: of 11,408 studies screened from 2000 to 2024, 68 articles reporting 66 studies were eligible and only 45 were rated low or moderate risk of bias, with the literature thin in pregnancy, lactation, infancy and childhood, and the adult requirement studies for protein, leucine, methionine, phenylalanine, threonine and valine done in males only — lysine being one of the few amino acids studied across most life stages 13. And in the oldest adults the figure appears simply too low: by indicator amino acid oxidation, women over 70 need close to 50% more lysine than the current recommendation 14.
Plant protein supplies about 65% of the world’s protein, and cereals are low in lysine 2. Mixtures of plant proteins can still meet every requirement 2: moist-cooked sorghum had lysine that was 94% available, and adding lentils improved the meal’s protein value further 3. In practice, in a real population, that holds only on paper. Four-day food diaries from 193 New Zealand vegans scored for indispensable amino acids gave 35.7 mg of lysine per gram of protein against a reference pattern of 45, and lysine intake of 31.0 mg/kg/day against the 30 mg/kg/day requirement — just meeting it. Once true ileal digestibility was applied, only about half the cohort met the lysine requirement, and lysine and leucine were the two most limiting amino acids 15. The arithmetic of complementary proteins is correct; the margin it leaves, after digestibility, is thinner than the arithmetic suggests.
EssentialMust come from food; the adult requirement is 30 mg per kilogram a day 1. Indian men on long-term controlled diets needed 31 mg/kg, against the 12 mg/kg set in 1985 7.
In the bottle · fermentedLysine is one of the largest-volume products of industrial fermentation, about 2.2 million tonnes a year, made almost entirely by mutant strains of Corynebacterium glutamicum, most of it for animal feed 16,17. It is the same molecule as in food.
What the body does with it
Collagen and elastin owe their strength to cross-links made from lysine. The five lysyl oxidases, copper-dependent enzymes, oxidize lysine side chains in the assembled fibers, and the resulting aldehydes link neighboring strands 4. A separate enzyme, lysyl hydroxylase 1, adds a hydroxyl first; its loss causes the kyphoscoliotic form of Ehlers–Danlos syndrome 18,19.
Lysine is also the backbone of carnitine, which carries fatty acids into mitochondria. The body builds carnitine from lysines that have been trimethylated while still part of proteins, and then released when those proteins are broken down 20.
Infused in large amounts, lysine competes with radiolabeled peptides for uptake by the kidney. Given with arginine during radionuclide therapy of neuroendocrine tumors, it cut renal uptake by about a third, with fewer side effects than lysine alone, which raised potassium dangerously in some patients 21.
Lysine's effect on insulin was known; the reason for it was wrong. Lysine is insulinotropic in people, and the textbook explanation was that it depolarizes the beta-cell membrane, as arginine does, because it is positively charged. In fact the effect runs through catabolism inside the cell: the lysine degradation genes AASS, ALDH7A1, DHTKD1 and HADH are expressed in human pancreatic islets and in a beta-cell line, and are downregulated in islets from donors with type 2 diabetes. Silencing AASS in human islets and in the cell line reduced glucose-stimulated insulin secretion, with altered GABA metabolism, less GABA, glutamate piling up, impaired Krebs-cycle and oxidative-phosphorylation function, a fallen ATP/ADP ratio and a risen lactate/pyruvate ratio 22. The saccharopine pathway this page calls a liver-and-brain route turns out to be load-bearing in the beta cell.
Lysine is also something tumors compete for, and this is the one context where supplementing it has a mechanism rather than a slogan. Hepatocellular carcinoma cells express high levels of the lysine transporter SLC3A2 and outcompete T cells for the amino acid; deprived of lysine, T cells lose STAT3, stop proliferating and lose effector function. High SLC3A2 tracked poor survival and disordered T-cell gene signatures in patients, lenvatinib induced a c-Myc–SLC3A2 axis that limited its own effect, and supplementing lysine made tumors more sensitive to lenvatinib with anti-PD-1 23. All of that is preclinical, and it is the opposite of a reason to take lysine tablets for anything — it is a reason to study dose and timing alongside a specific drug.
In three sentences each
The limiting amino acid in cereals
Cereal proteins are low in lysine and legumes are rich in it, so mixtures of plant proteins can meet every requirement; adding lentils to sorghum lowered the indicator of unmet need by 19% in one tracer study 2,3.
A handle for cross-links
Lysyl oxidases, copper enzymes, turn lysine side chains in collagen and elastin into reactive aldehydes, the first step of the cross-links that give these proteins their strength 4.
How it is made, moved and broken down
Lysine is broken down mainly through saccharopine, a pathway confined to mitochondria; a second route through pipecolic acid matters more in the brain, though how much is still debated 10,24. Five inherited disorders affect the pathway. Two are severe, pyridoxine-dependent epilepsy and glutaric aciduria type 1; three, including hyperlysinemia, appear to have no clinical consequences 10,25.
The pathway's intermediates are not only waypoints. Glutaconic acid, a lysine catabolite whose production depends on medium-chain acyl-CoA dehydrogenase, turns out to be immunostimulatory for antitumor CD8 T cells, and it works by modifying lysines in turn: glutaconylation of pyruvate kinase M2 at K336 and K337 reinforces PKM2 dimers and reprogrammes the cell's metabolism. Tumors exploit this by running an amino acid trade-off — upregulating SLC7A1 to use more arginine for growth while downregulating SLC7A2 to suppress lysine catabolism, which lowers glutaconic acid and helps them evade immunity 26. A breakdown product of lysine that modifies lysines is as close to a closed loop as this page gets.
Carbon skeleton · ketogenicBroken down in mitochondria, mostly through saccharopine, to glutaryl-CoA and on to acetyl-CoA, so none of its carbon can make glucose 10,27.
- Lysine + 2-oxoglutarate
- α-Aminoadipic semialdehyde synthaseAASS · NADPH
- Saccharopine
- AASS (second domain)AASS · NAD⁺
- α-Aminoadipic semialdehyde
- AntiquitinALDH7A1 · NAD⁺
- α-Aminoadipate
- Glutaryl-CoA dehydrogenaseGCDH · FAD
- Crotonyl-CoA → acetyl-CoA
- Lysine in collagen
- Lysyl oxidaseLOX, LOXL1–4 · copper
- Allysine (an aldehyde)
- Trimethyllysine (from protein)
- Four enzymesTMLHE, BBOX1 · iron, vitamin C
- Carnitine
How it crosses membranes
- SLC7A7 · y⁺LAT1, with CD98the blood side of gut and kidney cells — exports lysine, arginine and ornithine; its loss causes lysinuric protein intolerance 29
- SLC3A1, SLC7A9 · rBAT, b⁰,⁺ATthe gut and kidney lumen — reclaims lysine with cystine and the other basic amino acids; mutations cause cystinuria 30
Where it matters most
When it goes wrong
Inherited
Pyridoxine-dependent epilepsy
ALDH7A1 · autosomal recessive
Seizures, often from birth, that stop with pyridoxine because the accumulating lysine product inactivates vitamin B6 28. Guidelines add a lysine-restricted diet and arginine, but most patients have developmental delay or intellectual disability despite seizure control 31. The first real attempt on that residual damage is to block the pathway one step further upstream than diet can. Crossing a mouse lacking AASS — the first enzyme of lysine breakdown, and the hyperlysinemia model — with a new CRISPR-made model of the disease significantly reduced the putatively neurotoxic metabolites Δ¹-piperideine-6-carboxylate, pipecolic acid, 6-oxo-pipecolic acid and 2-OPP in brain and liver, and in plasma too, which would also give a way to monitor it 32. In patient-derived stem cells differentiated into astrocytes — the brain's main site of lysine handling — the disease markers came with oxidative stress, DNA oxidation, lipid peroxidation and mitochondrial dysfunction, and knocking AASS down, by CRISPR editing or by an antisense oligonucleotide, relieved all of it 33. A mouse and a dish; but they name both the target and the drug class.
How it is foundUrine α-aminoadipic semialdehyde and ALDH7A1 sequencing; blood-spot screening is being tested 31,34.
Inherited
Glutaric aciduria type 1
GCDH · autosomal recessive
Without treatment, an illness or fast in the first years of life can destroy the striatum and leave a severe movement disorder. Newborn screening, a low-lysine diet, carnitine and emergency treatment during illness prevent most of it; the diet can be relaxed after age six 27. What 'most of it' means is visible where screening does not happen. In 50 patients diagnosed at two Turkish centers, in a country where the disease is not on the national newborn panel, the median age at diagnosis was 10 months, two-thirds presented acutely, 66% had encephalopathic crises — usually set off by gastroenteritis or a respiratory infection — 61.5% ended at the most severe level of the gross motor classification, 86.1% had basal ganglia involvement on imaging, and 12 of the 50 died during follow-up at a median age of 6.2 years 35. The low-lysine diet is one of the few amino-acid interventions whose value is not in doubt, and this is why.
How it is foundGlutarylcarnitine on newborn screening, urine glutaric and 3-hydroxyglutaric acid, GCDH sequencing 27.
Inherited
Lysinuric protein intolerance
SLC7A7 · autosomal recessive
The gut and kidney cannot export lysine, arginine and ornithine, so they are lost and the urea cycle runs short, with hyperammonemia after protein 29. In a Paris cohort of 16 followed for a mean of 11 years, ten presented with hyperammonemia, all had kidney disease, and six died, at a mean age of four, of pulmonary alveolar proteinosis 36. There is a third organ system the older descriptions leave out. In ten patients against 18 age-matched controls, the condition came with a combined immune and metabolic phenotype: reduced B cells and class-switched memory B cells with IgG deficiency, impaired lymphocyte proliferation despite normal T-cell numbers, and lower IL-17 and IL-4 responses with interferon-γ relatively preserved. Mitogenic stimulation produced a coordinated amino acid response in controls and an altered one in patients, citrulline included 37. On this reading the immune failure is a core feature rather than a complication.
How it is foundPlasma and urine dibasic amino acids, SLC7A7 sequencing 29,36.
Inherited
Hyperlysinemia
AASS · autosomal recessive
High plasma lysine from loss of the first enzyme of breakdown; generally a benign metabolic variant 25.
How it is foundPlasma lysine and AASS sequencing 25.
Inherited
Kyphoscoliotic Ehlers–Danlos syndrome
PLOD1, FKBP14 · autosomal recessive
Lysyl hydroxylase 1 deficiency disrupts collagen cross-linking, causing low muscle tone at birth, progressive spinal curvature and fragile tissues 18,19.
How it is foundMolecular confirmation, required for every Ehlers–Danlos type except the hypermobile one; an altered urine ratio of lysyl to hydroxylysyl pyridinoline supports the diagnosis 19,38.
How it is measured
Plasma lysine is part of the routine amino acid panel, and like the others it shifts with how the sample is stored and which tube it was drawn into 39. The disease markers are downstream: glutarylcarnitine for glutaric aciduria type 1, and α-aminoadipic semialdehyde and its partners for pyridoxine-dependent epilepsy 27,28,34.
For pyridoxine-dependent epilepsy the classical markers are the obstacle to screening, not the answer: α-aminoadipic semialdehyde and piperideine-6-carboxylate are unstable at room temperature, and pipecolate on its own is not specific enough. A 2025 study ran two newer stable markers as a single multiplex assay on 9,402 dried blood spots — 9 confirmed patients and 9,393 anonymized controls — inside the butanol-derivatized workflow screening laboratories already use. 2-OPP alone found all nine (100% sensitivity) at a positive predictive value of 18.4%; adding pipecolate or 6-oxo-pipecolate as a second marker raised that to 60% and 45%; and raising the 2-OPP threshold with either second marker gave 100% sensitivity at 100% predictive value 40. That is what it would take to put the disorder on a newborn panel.
- Plasma amino acidsLysine is measured in the standard plasma amino acid panel, high in hyperlysinemia and low in lysinuric protein intolerance 25,36.Reliable with prompt handling; heparin plasma was the most stable sample type in one comparison 39.Levels drift with storage time and tube type before analysis 39.
- Urine and blood markers of lysine breakdownGlutarylcarnitine in newborn screening for glutaric aciduria type 1, and α-aminoadipic semialdehyde in urine for pyridoxine-dependent epilepsy 27,28.Newborn screening for glutaric aciduria type 1 is established; for pyridoxine-dependent epilepsy, new blood-spot markers were raised in 7 or 8 of 8 cases in a feasibility study 27,34.Some people with glutaric aciduria type 1 excrete little of the marker and can be missed 27.
Food, supplements and the evidence
Establishedreplicated in people, for a named outcome
Uncertainsmall, short, mixed, surrogate or preclinical
- Lysine for cold sores: one 1987 trial and smaller studies suggest benefit only above about 3 g a day, while a 2015 Cochrane review found no reliable evidence for prevention 41,42,43.
- Lysine-fortified flour lowered anxiety and stress hormones in a three-month trial in Syrian families; the first author worked for a lysine manufacturer 44. A 2025 mouse study points the other way: restricting lysine reduced anxiety-like behavior from a high-fat diet while also lowering weight and improving glucose metabolism, through a remodeled gut microbiota, enrichment of Oscillibacter, and restoration of its metabolite tryptophol 45. A mouse cannot overturn a human trial. It does mean the direction of the mechanism is now contested, and the one human trial was written by an author working for a lysine manufacturer.
- Whether 30 mg/kg/day is right for an older adult. Indicator amino acid oxidation — the same method that produced the figure in use — gives higher requirements across the board in older people, and for lysine the effect depends on age AND sex: women over 70 need close to 50% more lysine than the current recommendation 14. The number on this page is a young adult's number.
Sold asthe claim on the label, against the evidence
- “Lysine stops cold sores.” The best summary of prevention trials, 32 trials of 19 treatments, found no evidence that lysine works 43.
What is strange about it
Pyridoxine-dependent epilepsy is a lysine disorder that looks like a vitamin deficiency. A lysine breakdown product that builds up when antiquitin fails reacts with the active form of vitamin B6 and inactivates it, so the seizures stop with large doses of pyridoxine 28.
Arginine is used as a drug against a lysine disorder: it competes with lysine for transport, so in pyridoxine-dependent epilepsy it is given with a lysine-restricted diet 31,46.
The trial that launched lysine for cold sores, in 1987, found 2.4 fewer outbreaks over six months on 3 g a day; a 2015 Cochrane review of 32 trials of prevention found no good evidence that lysine works 41,43.
Lysine's best-known consumer claim is that it fights herpes. Herpesviruses use modified lysines to escape the immune system. Human cytomegalovirus drives aerobic glycolysis and uses the resulting lactate to lactylate lysines across the proteome, enriched in intrinsically disordered regions where the modification governs viral protein condensates and immune signaling; lactylation of the DNA sensor IFI16 at K90 blocks recruitment of DNA-PK, which prevents IFI16 from repressing viral genes and inducing cytokines. The same trick is shared with herpes simplex virus 1 47. The amino acid sold to stop cold sores is, in its modified form, part of how the virus hides.
Two recent papers on this page's subject matter have been withdrawn, and both are worth naming. The most ambitious extension of industrial lysine fermentation — a self-regulating platform making lysine-derived alkaloids from glucose, with reported titres of 6.11 g/L of pelletierine, 8.60 g/L of piperidine and 3.71 g/L of sedridine — is indexed by PubMed as a retracted publication 48. So is a 2025 Nature paper reporting that inhibiting the histone-lysine methyltransferase NSD2 reverses plasticity and drug resistance in prostate cancer 49. Lysine-modifying enzymes are now a drug class, which is exactly why a retraction among them belongs on the page next to the mechanism.
Where it connects
In the Atlas
Topics on the map
On the map
A star in The essential amino acids, one of 14. The limiting amino acid in cereal protein, and the reason a grain and a legume together do what neither does alone.
Sources
49 sources, numbered as they are cited. Every one was checked against PubMed or its publisher before it was cited here; the note under each says what it shows and what it does not.
- 1Joint WHO/FAO/UNU Expert Consultation. Protein and amino acid requirements in human nutrition.PMID 18330140
Lysine, 30 mg/kg/day.
- 2Young VR, Pellett PL. Plant proteins in relation to human protein and amino acid nutrition.doi:10.1093/ajcn/59.5.1203S · PMID 8172124
Plant protein is 65% of world supply; mixtures are complete.
- 3Paoletti A, Fakiha A, Tul-Noor Z, et al. Bioavailable lysine assessed using the indicator amino acid oxidation method in healthy young males is high when sorghum is cooked by a moist cooking method.doi:10.1093/jn/nxab410 · PMID 34871427
Five men; lysine 94% available; lentils lowered indicator oxidation 19%.
- 4Vallet SD, Ricard-Blum S. Lysyl oxidases: from enzyme activity to extracellular matrix cross-links.doi:10.1042/EBC20180050 · PMID 31488698
Five copper enzymes start collagen and elastin cross-linking.
- 5Strahl BD, Allis CD. The language of covalent histone modifications.doi:10.1038/47412 · PMID 10638745
The histone code hypothesis.
- 6Komander D, Rape M. The ubiquitin code.doi:10.1146/annurev-biochem-060310-170328 · PMID 22524316
Ubiquitin joined to lysines by isopeptide bonds.
- 7Kurpad AV, Regan MM, Raj T, et al. Lysine requirements of healthy adult Indian subjects receiving long-term feeding, measured with a 24-h indicator amino acid oxidation and balance technique.doi:10.1093/ajcn/76.2.404 · PMID 12145014
18 men; requirement about 31 mg/kg/day against 12 in 1985.
- 8Kurpad AV, Regan MM, Raj T, et al. Lysine requirements of chronically undernourished adult Indian men, measured by a 24-h indicator amino acid oxidation and balance technique.doi:10.1093/ajcn/77.1.101 · PMID 12499329
27 undernourished men; 44 mg/kg/day.
- 9Hayamizu K, Oshima I, Fukuda Z, et al. Safety assessment of L-lysine oral intake: a systematic review.doi:10.1007/s00726-019-02697-3 · PMID 30661148
71 studies; provisional NOAEL 6 g/day.
- 10Leandro J, Houten SM. The lysine degradation pathway: subcellular compartmentalization and enzyme deficiencies.doi:10.1016/j.ymgme.2020.07.010 · PMID 32768327
Saccharopine and pipecolic pathways; two severe and three benign disorders.
- 11Choudhary C, Kumar C, Gnad F, et al. Lysine acetylation targets protein complexes and co-regulates major cellular functions.doi:10.1126/science.1175371 · PMID 19608861
3,600 acetylation sites on 1,750 proteins.
- 12Song X, Peng P, Zheng H, et al. Lysine pyruvylation couples glycolytic flux to epigenetic regulation.doi:10.1038/s42255-026-01556-2 · PMID 42399660
88 sites, with a writer, an eraser, and a rate set by how fast the cell is burning sugar.
- 13Burstad KM, Lamina T, Erickson A, et al. Evaluation of dietary protein and amino acid requirements: a systematic review.doi:10.1016/j.ajcnut.2025.04.017 · PMID 40610129
An audit of the evidence behind the reference values, commissioned because they have not been revised since 2005.
- 14Courtney-Martin G. Amino acid requirements of older adults: time to consider separate recommendations from young adults.doi:10.1097/MCO.0000000000001188 · PMID 41259227
The same method that produced the figure in use, applied to the people it was never measured in.
- 15Soh BXP, Vignes M, Smith NW, von Hurst PR, McNabb WC. Evaluation of protein intake and protein quality in New Zealand vegans.doi:10.1371/journal.pone.0314889 · PMID 40238722
193 four-day food diaries, scored for amino acids and then corrected for true ileal digestibility. The correction is what changes the answer.
- 16Eggeling L, Bott M. A giant market and a powerful metabolism: L-lysine provided by Corynebacterium glutamicum.doi:10.1007/s00253-015-6508-2 · PMID 25761623
About 2.2 million tonnes a year.
- 17Liu J, Xu JZ, Rao ZM, Zhang WG. Industrial production of L-lysine in Corynebacterium glutamicum: progress and prospects.doi:10.1016/j.micres.2022.127101 · PMID 35803058
Uses in food, medicine and animal feed.
- 18Colman M, Vroman R, Dhooge T, et al. Kyphoscoliotic Ehlers-Danlos syndrome caused by pathogenic variants in FKBP14: further insights into the phenotypic spectrum and pathogenic mechanisms.doi:10.1002/humu.24456 · PMID 36054293
PLOD1 and FKBP14 forms of kEDS.
- 19Malfait F, Francomano C, Byers P, et al. The 2017 international classification of the Ehlers-Danlos syndromes.doi:10.1002/ajmg.c.31552 · PMID 28306229
Thirteen types; all but hypermobile need molecular confirmation.
- 20Vaz FM, Wanders RJ. Carnitine biosynthesis in mammals.doi:10.1042/0264-6021:3610417 · PMID 11802770
Carnitine from protein-bound trimethyllysine.
- 21Rolleman EJ, Valkema R, de Jong M, et al. Safe and effective inhibition of renal uptake of radiolabelled octreotide by a combination of lysine and arginine.doi:10.1007/s00259-002-0982-3 · PMID 12483404
Lysine alone cut renal uptake 44% but raised potassium; with arginine 33%.
- 22Muñoz F, Gao Q, Mattanovich M, et al. Lysine potentiates insulin secretion via AASS-dependent catabolism and regulation of GABA content and signaling.doi:10.1016/j.metabol.2025.156423 · PMID 41167553
Human islets and a beta-cell line, with the assumed mechanism tested and replaced.
- 23Chang Y, Wang N, Li S, et al. SLC3A2-mediated lysine uptake by cancer cells restricts T-cell activity in hepatocellular carcinoma.doi:10.1158/0008-5472.CAN-24-3180 · PMID 40126539
Preclinical, and the rare case where supplemental lysine has a mechanism behind it rather than a slogan.
- 24Guo Y, Wu J, Guo W. The neuropathological mechanisms underlying the inborn errors of lysine metabolism.doi:10.1016/j.nbd.2026.107315 · PMID 41666987
Which pathway dominates in the brain remains contested.
- 25Houten SM, te Brinke H, Denis S, et al. Genetic basis of hyperlysinemia.doi:10.1186/1750-1172-8-57 · PMID 23570448
AASS variants; a generally benign metabolic variant.
- 26Yu W, Sun R, Lu X, et al. Dynamic regulation of lysine and arginine metabolism promotes immune evasion by limiting T cell function in cancer.doi:10.1126/sciimmunol.aeb7315 · PMID 42497246
A lysine catabolite that modifies lysines. The loop this page's structure section exists for.
- 27Boy N, Mühlhausen C, Maier EM, et al. Recommendations for diagnosing and managing individuals with glutaric aciduria type 1: third revision.doi:10.1002/jimd.12566 · PMID 36221165
Screening, diet, carnitine and emergency treatment.
- 28Mills PB, Struys E, Jakobs C, et al. Mutations in antiquitin in individuals with pyridoxine-dependent seizures.doi:10.1038/nm1366 · PMID 16491085
The lysine product inactivates pyridoxal phosphate.
- 29Torrents D, Mykkänen J, Pineda M, et al. Identification of SLC7A7, encoding y+LAT-1, as the lysinuric protein intolerance gene.doi:10.1038/6809 · PMID 10080182
The basolateral dibasic amino acid transporter.
- 30Servais A, Thomas K, Dello Strologo L, et al. Cystinuria: clinical practice recommendation.doi:10.1016/j.kint.2020.06.035 · PMID 32918941
rBAT and b⁰,⁺AT reclaim cystine and the basic amino acids.
- 31Coughlin CR, Tseng LA, Abdenur JE, et al. Consensus guidelines for the diagnosis and management of pyridoxine-dependent epilepsy due to α-aminoadipic semialdehyde dehydrogenase deficiency.doi:10.1002/jimd.12332 · PMID 33200442
Pyridoxine, lysine restriction and arginine.
- 32van Karnebeek CDM, Gailus-Durner V, Engelke UF, et al. New treatment for pyridoxine-dependent epilepsy due to ALDH7A1 deficiency: first proof-of-principle of upstream enzyme inhibition in the mouse.doi:10.1093/braincomms/fcaf397 · PMID 41221123
Two knockouts crossed, and the neurotoxic metabolites measured in brain, liver and plasma. Mice.
- 33Schuurmans IME, Engelke U, Abedrabbo M, et al. Targeting AASS alleviates neurotoxicity and improves mitochondrial function in astrocyte models for pyridoxine-dependent epilepsy.doi:10.1016/j.omtn.2025.102728 · PMID 41158987
Patient cells, and the modality that would carry the mouse result into a clinic: an antisense oligonucleotide.
- 34Pauly K, Woontner M, Abdenur JE, et al. Feasibility of newborn screening for pyridoxine-dependent epilepsy.doi:10.1016/j.ymgme.2024.109002 · PMID 39729892
Two blood-spot markers raised in 7 and 8 of 8 cases; small study.
- 35Selamioğlu A, İdrisoğlu M, Kılıç Ş, et al. Glutaric acidemia type 1 in a non-newborn-screened cohort: clinical, biochemical, and molecular features and neurologic outcomes.doi:10.1186/s13052-026-02284-9 · PMID 42210298
50 patients in a country where the disease is not screened for. The counterfactual, with numbers.
- 36Mauhin W, Habarou F, Gobin S, et al. Update on lysinuric protein intolerance, a multi-faceted disease: retrospective cohort analysis from birth to adulthood.doi:10.1186/s13023-016-0550-8 · PMID 28057010
16 patients followed from birth.
- 37Karaaslan BG, Zeybek ACA, Burtecene N, et al. Metabolic alterations associated with immune dysfunction in lysinuric protein intolerance.doi:10.1016/j.ymgme.2026.110253 · PMID 42667713
Ten patients, 18 controls, flow cytometry and amino acid profiling together.
- 38Conti R, Zanchi C, Barbi E. A floppy infant without lingual frenulum and kyphoscoliosis: Ehlers Danlos syndrome case report.doi:10.1186/s13052-021-00984-y · PMID 33579342
Case report; the urine pyridinoline ratio.
- 39Xia T, Gao S, Shu C, et al. Analysis of amino acids in human blood using UHPLC-MS/MS: potential interferences of storage time and vacutainer tube in pre-analytical procedure.doi:10.1016/j.clinbiochem.2016.09.018 · PMID 27693603
25 people; heparin plasma most stable.
- 40Donge M, Marie S, Pochet A, et al. Advancing neonatal screening for pyridoxine-dependent epilepsy-ALDH7A1 through combined analysis of 2-OPP, 6-oxo-pipecolate and pipecolate in a butylated FIA-MS/MS workflow.doi:10.3390/ijns11030059 · PMID 40843901
9,402 dried blood spots, inside the workflow screening laboratories already run.
- 41Griffith RS, Walsh DE, Myrmel KH, et al. Success of L-lysine therapy in frequently recurrent herpes simplex infection: treatment and prophylaxis.PMID 3115841
1 g three times a day for six months; 27 against 25 completers.
- 42Mailoo VJ, Rampes S. Lysine for herpes simplex prophylaxis: a review of the evidence.PMID 30881246
Below 1 g/day ineffective; above 3 g/day possibly helpful; longer trials needed.
- 43Chi CC, Wang SH, Delamere FM, et al. Interventions for prevention of herpes simplex labialis (cold sores on the lips).doi:10.1002/14651858.CD010095.pub2 · PMID 26252373
32 trials, 2,640 people; no evidence for lysine.
- 44Smriga M, Ghosh S, Mouneimne Y, et al. Lysine fortification reduces anxiety and lessens stress in family members in economically weak communities in Northwest Syria.doi:10.1073/pnas.0402550101 · PMID 15159538
Three-month randomized trial; first author affiliated with a lysine manufacturer.
- 45Zhao F, Wang J, Liang W, et al. Lysine restriction attenuates obesity-related anxiety-like behaviors via increasing Oscillibacter ruminantium-mediated tryptophol regulation.doi:10.1186/s40168-025-02217-4 · PMID 41316428
Mice, and the opposite direction to the human fortification trial this page already carries.
- 46Jafari A, Abbasi MM, Abbasi H, et al. Combination therapy with pyridoxine and arginine supplementations along with a lysine-restricted diet in individuals with pyridoxine-dependent epilepsy: a comprehensive systematic review.doi:10.1016/j.cdnut.2025.107504 · PMID 40800672
38 observational studies; early triple therapy looked best.
- 47Tyl MD, Merengwa VU, Cristea IM. Infection-induced lysine lactylation enables herpesvirus immune evasion.doi:10.1126/sciadv.ads6215 · PMID 39772686
Two herpesviruses using modified lysines to switch off the immune response. One residue, IFI16 K90, carries much of it.
- 48Lin P, Lee SY. A dual self-regulatory platform for programmable biosynthesis of L-lysine-derived alkaloids.doi:10.1073/pnas.2612082123 · PMID 42475578
Indexed by PubMed as a Retracted Publication. The titres below are quoted from a paper that has been withdrawn.
- 49Li JJ, Vasciaveo A, Karagiannis D, et al. NSD2 targeting reverses plasticity and drug resistance in prostate cancer.doi:10.1038/s41586-025-09727-z · PMID 41299174
Indexed by PubMed as a Retracted Publication. Named here because lysine-modifying enzymes are now a drug class.
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