{"ATC Code":"V - Various","Abbreviation":["Met"],"Absorption, Distribution and Excretion":"Absorbed from the lumen of the small intestine into the enterocytes by an active transport process.","Boiling Point":"sublimes at 367 °F (NTP, 1992)","CAS":"63-68-3","Chemical Classes":"Biological Agents -\u003e Amino Acids and Derivatives","ChemicalClasses":["amino acid"],"Chirality":"absolute","ChiralityAminoAcid":true,"Color/Form":"Minute hexagonal plates from dilute alcohol","Decomposition":"When heated to decomposition it emits very toxic fumes of /nitric oxide/ and /sulfur oxide/.","Density":"1.178 at 68 °F (NTP, 1992) - Denser than water; will sink g/cm\u003csup\u003e3\u003c/sup\u003e","Drug Indication":"Used for protein synthesis including the formation of SAMe, L-homocysteine, L-cysteine, taurine, and sulfate.","Drug Warnings":"Methionine may cause nausea, vomiting, drowsiness, and irritability. It should not be used in patients with acidosis. Methionine may aggravate hepatic encephalopathy in patients with established liver damage; it should be used with caution in patients with severe liver disease.","Ecotoxicity Values":"LC50; Species: Eisenia fetida (earthworm, mature, weight 370-450 mg) direct application using filter paper \u003e1000 AI ug/sq cm for 48 hr","Esters":[],"European Community (EC) Number":"200-562-9","Formating":[],"HMDB ID":"HMDB0000696","Health Effects":"Chronically high levels of methionine are associated with at least 7 inborn errors of metabolism including: Cystathionine Beta-Synthase Deficiency, Glycine N-methyltransferase Deficiency, Homocystinuria-megaloblastic anemia due to defect in cobalamin metabolism, Methionine Adenosyltransferase Deficiency, Methylenetetrahydrofolate reductase deficiency and S-Adenosylhomocysteine (SAH) Hydrolase Deficiency.","HeavyAtomCount":9,"IUPACName":"(2S)-2-amino-4-methylsulfanylbutanoic acid","InChI":"InChI=1S/C5H11NO2S/c1-9-3-2-4(6)5(7)8/h4H,2-3,6H2,1H3,(H,7,8)/t4-/m0/s1","InChIKey":"FFEARJCKVFRZRR-BYPYZUCNSA-N","Interactions":"The adverse effects of methionine are alleviated by supplements of glycine or serine ... Vit B6 deficiency reduces the tolerance of the rat for methionine.","KEGG Entries":[{"Id":"D00019","Interactions":[],"Synonyms":["Methionine","L-Methionine"]},{"Id":"D00177","Interactions":[],"Synonyms":["Methylmethionine sulfonium chloride","L-Methylmethionine sulfonium chloride","Cabagin U"]},{"Id":"D04983","Interactions":[],"Synonyms":["Racemethionine","DL-Methionine","Padameth"]},{"Id":"D04984","Interactions":[],"Synonyms":["Methionine C 11","Carbon-11 methionine"]},{"Id":"D04993","Interactions":[],"Synonyms":["Monoammonium glycyrrhizinate, glycine and DL-methionine","Glycyron"]},{"Id":"D05816","Interactions":[],"Synonyms":["Selenomethionine Se 75","Sethotope"]},{"Id":"D07592","Interactions":[],"Synonyms":["Ademetionine tosilate disulfate","S-Adenosylmethionine disulfate ditosylate","Gumbaral"]},{"Id":"D08704","Interactions":[],"Synonyms":["Magnesium aluminometasilicate, methylmethionine sulfonium chloride, magnesium carbonate and precipitated calcium carbonate","Cabagin-U"]},{"Id":"D08747","Interactions":[],"Synonyms":["DL-Methionine and glycyrrhizic acid","Licothion"]}],"Mechanism of Action":"The mechanism of the possible anti-hepatotoxic activity of L-methionine is not entirely clear. It is thought that metabolism of high doses of acetaminophen in the liver lead to decreased levels of hepatic glutathione and increased oxidative stress. L-methionine is a precursor to L-cysteine. L-cysteine itself may have antioxidant activity. L-cysteine is also a precursor to the antioxidant glutathione. Antioxidant activity of L-methionine and metabolites of L-methionine appear to account for its possible anti-hepatotoxic activity. Recent research suggests that methionine itself has free-radical scavenging activity by virtue of its sulfur, as well as its chelating ability.","Melting Point":"536 to 540 °F decomposes 541.4-543.2 °F (NTP, 1992)","Metabolism/Metabolites":"Hepatic","MolecularFormula":"C\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e11\u003c/sub\u003eNO\u003csub\u003e2\u003c/sub\u003eS","MolecularWeight":"149.21 g/mol","Non-Human Toxicity Values":"LD50 Rat oral 36,000 mg/kg","Odor":"Faint","Opticalactivity":"UNSPECIFIED","Pharmacodynamics":"L-Methionine is a principle supplier of sulfur which prevents disorders of the hair, skin and nails; helps lower cholesterol levels by increasing the liver's production of lecithin; reduces liver fat and protects the kidneys; a natural chelating agent for heavy metals; regulates the formation of ammonia and creates ammonia-free urine which reduces bladder irritation; influences hair follicles and promotes hair growth. L-methionine may protect against the toxic effects of hepatotoxins, such as acetaminophen. Methionine may have antioxidant activity.","Physical Description":"Minute hexagonal plates from dilute alcohol. (NTP, 1992)","PubChemId":6137,"Records":{"UNII":{"Impurities":["methionine sulfone","ammonium cation","iron","(2s)-2-(((2rs)-2-(acetylamino)-4-(methylsulfanyl)butanoyl)amino)-4-(methylsulfanyl)butanoic acid","(2r)-2-(((2rs)-2-(acetylamino)-4-(methylsulfanyl)butanoyl)amino)-4-(methylsulfanyl)butanoic acid","n-acetylmethionine, dl-","chloride ion","methionine sulfoxide","sulfate ion"]}},"RefCount":3,"RefCur":"","References":[{"Name":"Wikipedia","Urls":[{"Link":"https://en.wikipedia.org/wiki/Methionine","Name":"Methionine","Sub":false}]},{"Name":"Wikidata","Urls":[{"Link":"https://www.wikidata.org/wiki/Q22124685","Name":"Methionine","Sub":false}]},{"Name":"DrugBank","Urls":[{"Link":"https://go.drugbank.com/drugs/DB00134","Name":"Methionine","Sub":false}]},{"Name":"PubChem","Urls":[{"Link":"https://pubchem.ncbi.nlm.nih.gov/compound/6137","Name":"Methionine","Sub":false}]},{"Name":"Common Chemistry","Urls":[{"Link":"https://commonchemistry.cas.org/detail?cas_rn=63-68-3","Name":"Methionine","Sub":false}]},{"Name":"HMDB","Urls":[{"Link":"https://hmdb.ca/metabolites/HMDB0000696","Name":"Methionine","Sub":false}]},{"Name":"KEGG","Urls":[{"Link":"https://www.kegg.jp/entry/C00073","Name":"Methionine","Sub":false}]},{"Name":"UNII","Urls":[{"Link":"https://gsrs.ncats.nih.gov/ginas/app/ui/substances/AE28F7PNPL","Name":"Methionine","Sub":false}]},{"Name":"EPA DSSTox","Urls":[{"Link":"https://comptox.epa.gov/dashboard/chemical/details/DTXSID5040548","Name":"Methionine","Sub":false}]}],"Refs":["National Center for Biotechnology Information. PubChem Compound Summary for CID 6137, L-Methionine. Accessed December 19, 2025. \u003ca href=https://pubchem.ncbi.nlm.nih.gov/compound/6137\u003ehttps://pubchem.ncbi.nlm.nih.gov/compound/6137\u003c/a\u003e","U.S. Food and Drug Administration; National Center for Advancing Translational Sciences. Methionine. UNII: AE28F7PNPL. Global Substance Registration System. Accessed December 19, 2025. \u003ca href=https://gsrs.ncats.nih.gov/ginas/app/beta/substances/AE28F7PNPL\u003ehttps://gsrs.ncats.nih.gov/ginas/app/beta/substances/AE28F7PNPL\u003c/a\u003e"],"SMILES":"CSCC[C@@H](C(=O)O)N","SaltData":[],"Salts":[],"Solubility":"Soluble (NTP, 1992)","StereoisomerData":[],"Stereoisomers":[],"Structure":"\u003csvg xmlns=\"http://www.w3.org/2000/svg\" preserveAspectRatio=\"none\" style=\"display:block\" viewBox=\"0 0 87.353 45.68\"\u003e\u003crect width=\"100%\" height=\"100%\" fill=\"#fff\"/\u003e\u003cdesc\u003eGenerated by the Chemistry Development Kit (http://github.com/cdk)\u003c/desc\u003e\u003cg fill=\"#ff0d0d\" stroke=\"#000\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\".7\"\u003e\u003cpath fill=\"#fff\" stroke=\"none\" d=\"M0 0h88v46H0z\"/\u003e\u003cg class=\"mol\"\u003e\u003cpath d=\"m1.038 25.941 10.455-6.036M16.994 19.913l10.441 6.028M27.435 25.941l13.198-7.62M40.633 18.321l13.198 7.62M53.831 25.941l13.198-7.62\" class=\"bond\"/\u003e\u003cg class=\"bond\"\u003e\u003cpath d=\"M65.81 19.025V7.002M68.249 19.025V7.002\"/\u003e\u003cpath stroke=\"#ff0d0d\" d=\"M65.81 7.002v6.011M68.249 7.002v6.011\" class=\"hi\"/\u003e\u003c/g\u003e\u003cpath d=\"m67.029 18.321 9.915 5.724\" class=\"bond\"/\u003e\u003cpath fill=\"#000\" stroke=\"none\" d=\"M54.181 25.941h-.7l-1.308 11.39h3.316z\" class=\"bond\"/\u003e\u003cpath fill=\"#c6c62c\" stroke=\"none\" d=\"M15.781 19.458q0 .649-.476 1.018-.47.363-1.268.363-.417 0-.768-.065-.345-.06-.577-.173v-.589q.244.113.607.202.369.09.762.09.547 0 .827-.215.28-.214.28-.577 0-.238-.107-.399-.101-.167-.351-.31t-.697-.297q-.625-.227-.946-.554-.316-.333-.316-.899 0-.393.197-.667.202-.279.553-.428.357-.155.816-.155.405 0 .738.077.339.072.613.197l-.196.53q-.25-.113-.548-.185-.298-.077-.625-.077-.458 0-.691.196-.232.197-.232.518 0 .244.101.411.108.167.34.298.232.125.631.279.428.155.726.34.298.178.452.434.155.25.155.637\" class=\"atom\"/\u003e\u003cpath stroke=\"none\" d=\"M69.289 3.078q0 .756-.256 1.328-.256.565-.757.881-.5.315-1.244.315-.756 0-1.262-.315-.506-.316-.756-.887-.244-.572-.244-1.334 0-.75.244-1.309.25-.566.756-.881T67.044.56q.732 0 1.232.316.501.309.757.875.256.565.256 1.327m-3.864 0q0 .923.387 1.459.393.53 1.22.53.84 0 1.221-.53.387-.536.387-1.459 0-.929-.387-1.452-.381-.524-1.209-.524-.833 0-1.226.524-.393.523-.393 1.452\" class=\"atom\"/\u003e\u003cg stroke=\"none\" class=\"atom\"\u003e\u003cpath d=\"M82.487 25.938q0 .756-.256 1.328-.256.565-.756.881-.5.315-1.244.315-.757 0-1.263-.315-.506-.316-.756-.887-.244-.572-.244-1.334 0-.75.244-1.309.25-.566.756-.881t1.274-.316q.733 0 1.233.316.5.309.756.875.256.565.256 1.327m-3.864 0q0 .923.387 1.459.393.53 1.221.53.839 0 1.22-.53.387-.536.387-1.459 0-.929-.387-1.452-.381-.524-1.209-.524-.833 0-1.226.524-.393.523-.393 1.452M86.793 28.391h-.619v-2.286h-2.512v2.286h-.614v-4.9h.614v2.072h2.512v-2.072h.619z\"/\u003e\u003c/g\u003e\u003cg fill=\"#3050f8\" stroke=\"none\" class=\"atom\"\u003e\u003cpath d=\"M55.772 43.631h-.721l-2.619-4.066h-.03l.03.595q.024.357.024.732v2.739h-.566v-4.9h.715l2.607 4.055h.03l-.018-.328-.024-.476q-.006-.262-.006-.482v-2.769h.578zM60.078 43.631h-.619v-2.286h-2.512v2.286h-.614v-4.9h.614v2.072h2.512v-2.072h.619zM62.583 45.12H60.64v-.3l.771-.778q.222-.222.372-.393.153-.175.232-.34.078-.167.078-.364 0-.243-.146-.368-.143-.128-.372-.128-.214 0-.378.075-.161.075-.329.207l-.193-.243q.172-.147.393-.247.225-.1.507-.1.411 0 .651.208.239.207.239.575 0 .228-.097.432-.092.2-.264.396-.168.197-.393.418l-.614.604v.018h1.486z\"/\u003e\u003c/g\u003e\u003cpath stroke=\"#c6c62c\" d=\"m11.493 19.905-5.227 3.018M16.994 19.913l5.221 3.014\" class=\"hi\"/\u003e\u003cpath stroke=\"#ff0d0d\" d=\"m76.944 24.045-4.957-2.862\" class=\"hi\"/\u003e\u003c/g\u003e\u003c/g\u003e\u003c/svg\u003e","Taste":"Sulfurous","Therapeutic Uses":"A sulfur containing essential amino acid that is important in many body functions. It is a chelating agent for heavy metals","Title":"Methionine","UNII":"AE28F7PNPL","Wikidata":"Q22124685","Wikipedia":"Methionine","XLogP":-1.9,"pH":"pH (1% aqueous solution) = 5.6-6.1"}