The initial detection of glycolaldehyde (CH₂OHCHO) was reported by Hollis et al. in 2000 in Sgr B2(N) using the NRAO 12 m telescope. Their title reflects that glycolaldehyde was the first sugar to be identified. It was also found in a colder part of the cloud several years later with the Green Bank telescope. Independent obsrvations by Halfen et al. in 2006 also confirmed its presence in Sgr B2(N).

Glycolaldehyde and two other observed astromolecules, acetic acid and methyl formate, comprise a set of stable isomers. There are two stable rotamers of glycolaldehyde, the more stable one above and a slightly less stable one shown to the right. It is only marginally accurate to call glycolaldehyde a sugar: most sugars include many hydroxyl groups rather than the single one in glycolaldehyde.