Malondialdehyde mainly exists as its enol, hydroxyacrolein:[2] In organic solvents, the cis-isomer is favored, whereas in water the trans-isomer predominates.

[3] It is a prominent product in thromboxane A2 synthesis wherein cyclooxygenase 1 or cycloxygenase 2 metabolizes arachidonic acid to prostaglandin H2 by platelets and a wide array of other cell types and tissues.

[5] This compound is a reactive aldehyde and is one of the many reactive electrophile species that cause toxic stress in cells and form covalent protein adducts referred to as "advanced lipoxidation end-products" (ALE), in analogy to advanced glycation end-products (AGE).

[12] Corneas of patients with keratoconus and bullous keratopathy have increased levels of malondialdehyde, according to one study.

[14] Levels of malondialdehyde can be also considered (as a marker of lipid peroxidation) to assess the membrane damage in spermatozoa; this is crucial because oxidative stress affects sperm function by altering membrane fluidity, permeability and impairing sperm functional competence.