N-Acetylserotonin (NAS), also known as normelatonin, is a naturally occurring chemical intermediate in the endogenous production of melatonin from serotonin.

[3] Subchronic and chronic administration of NAS to adult mice induces proliferation of neural progenitor cells (NPC)s, blockage of TrkB abolished this effect suggesting that it is TrkB-dependent.

[3] The SSRI fluoxetine and the MAO-A inhibitor clorgyline upregulate AANAT indirectly through serotonergic mechanisms and thereby increase NAS levels after chronic administration, and this correlates with the onset of their antidepressant effects.

[15][16] It reduces blood pressure in rodents, and pinealectomy (the pineal gland being a major site of NAS and melatonin synthesis) abolishes the hypotensive effects of clorgyline.

[15][16] NAS is produced from serotonin by the enzyme aralkylamine N-acetyltransferase (AANAT) and is converted to melatonin by acetylserotonin O-methyltransferase (ASMT).