The L-enantiomer of ascorbic acid, a water-soluble nutrient essential for life, synthesized by most animals and plants but not humans, although used in our bodies for many purposes. It is plentiful in citrus fruits and many vegetables, and a deficiency causes scurvy.

(slang, humorous) Ritalin, an amphetamine-like psychopharmaceutical, prescribed for ADHD.

Synonym of retinoic acid

(biochemistry) Any member of the vitamin B complex.

riboflavin

folic acid

Synonym of pyridoxine

pantothenic acid

thiamine

biotin