homocysteine

noun

ho·​mo·​cys·​te·​ine ˌhō-mō-ˈsi-stə-ˌēn  ˌhä- 

: an amino acid C₄H₉NO₂S that is produced in animal metabolism by the demethylation of methionine and that appears to be associated with an increased risk of cardiovascular disease when occurring at high levels in the blood

Examples of homocysteine in a Sentence

Recent Examples on the Web

For the study, researchers in Australia took blood samples from 172 middle-aged adults and checked their levels of magnesium, homocysteine, folate, and vitamin B12. —Nick Blackmer, Verywell Health, 11 Apr. 2025

There isn’t clear evidence, for example, that taking B vitamins to lower homocysteine levels actually reduces risk for heart problems. —IEEE Spectrum, 28 May 2015

Since high levels of homocysteine are linked to heart disease, methylated vitamins support cardiovascular health. —Allison Futterman, Discover Magazine, 7 Jan. 2025

According to the researchers, the toxic combination of low magnesium and high levels of homocysteine can increase the likelihood of contracting gastrointestinal disease, several cancers, diabetes, and Alzheimer's and Parkinson's diseases. —Killian Baarlaer, The Courier-Journal, 19 Dec. 2024

High levels of homocysteine are also linked to Alzheimer’s disease and dementia.11 Beets are also a good source of dietary nitrates, which the body converts into nitric oxide to improve blood flow, according to Mok. —Stephanie Brown, Verywell Health, 12 Oct. 2024

The folate in beets helps lower homocysteine levels, an amino acid that can damage blood vessels and contribute to heart disease. —Stephanie Brown, Verywell Health, 12 Oct. 2024

In addition to nootropics, the blueberry extract provides an antioxidant boost while vitamins B6 and B12 work together to regulate homocysteine metabolism. —Kelsey Kunik, Rd, Verywell Health, 25 Sep. 2024

Low magnesium and high homocysteine were linked to higher DNA damage biomarkers, which the researchers think could mean low magnesium is linked to a higher risk of DNA damage. —Nick Blackmer, Verywell Health, 9 Sep. 2024

Word History

Etymology

International Scientific Vocabulary hom- + cysteine

First Known Use

1932, in the meaning defined above

Medical Definition

homocysteine

noun

ho·​mo·​cys·​te·​ine ˌhō-mō-ˈsis-tə-ˌēn  ˌhäm-ō- 

: an amino acid C₄H₉NO₂S that is produced in animal metabolism by the demethylation of methionine and forms a complex with serine that breaks up to produce cysteine and homoserine and that appears to be associated with an increased risk of cardiovascular disease when occurring at high levels in the blood