1-Arachidonoyl-d8-rac-glycerol (1-AG-d8) serves as an internal standard for 1-AG quantification via GC or LC-MS. As a weak CB1 receptor agonist, 1-AG exhibits potential pharmacological effects. Notably, 1-AG, an isomer of 2-AG, is more stable, avoiding the rapid in vitro and in vivo isomerization that diminishes 2-AG's cannabinergic efficacy due to conversion to 1-AG (also known as 1(3)-AG), a common impurity in synthetic 2-AG formulations.