O-phosphoethanolamine is the ethanolamine mono-ester of phosphoric acid, and a metabolite of phospholipid metabolism. This phosphomonoester shows strong structural similarity to the inhibitory neurotransmitter GABA, and is decreased in post-mortem Alzheimer's disease brain. It has a role as a human metabolite, an algal metabolite and a mouse metabolite. It is a phosphoethanolamine and a primary amino compound. It is a conjugate acid of an O-phosphonatoethanaminium(1-).