ñ-Methylserotonin (ñMS), also known as ñ-methyl-5-hydroxytryptamine (ñ-methyl-5-HT) or as 5-hydroxy-ñ-methyltryptamine (5-HO-ñMT), is a tryptamine derivative closely related to the neurotransmitter serotonin (5-HT). It acts as a non-selective serotonin receptor agonist and has been used extensively in scientific research to study the function of the serotonin system.
According to Alexander Shulgin in his book TiHKAL (Tryptamines I Have Known and Loved), ñMS is well-studied in preclinical research but has not been tested in humans.
ñMS is a non-selective and near-full agonist of the serotonin 5-HT<sub>2</sub> receptors. It has similar affinity for the 5-HT<sub>2A</sub>, 5-HT<sub>2B</sub>, and 5-HT<sub>2C</sub> receptors. The drug is also a ligand of the serotonin 5-HT<sub>1</sub> receptors with high affinity, including of the serotonin 5-HT<sub>1A</sub>, 5-HT<sub>1B</sub>, and 5-HT<sub>1D</sub> receptors (K<sub>i</sub> = 40âÂÂ150nM), but not of the serotonin 5-HT<sub>1E</sub> receptor (K<sub>i</sub> > 10,000nM). In addition to its actions at the serotonin receptors, ñMS has been found to act as a norepinephrine releasing agent similarly to ñ-methylphenylalanine and to other ñ-alkylated tryptamines.
In contrast to DOI, and in spite of its potent serotonin 5-HT<sub>2A</sub> receptor agonism, ñMS did not produce the head-twitch response, a behavioral proxy of psychedelic effects, in rats. However, it was only assessed at a dose of up to 1mg/kg, which is around the maximally effective dose of DOI.
Unlike serotonin, ñMS is not metabolized by monoamine oxidase on account of the ñ-methyl substituent blocking the enzyme's access to the amine. Similarly to serotonin however, ñMS poorly crosses the bloodâÂÂbrain barrier due to its free hydroxyl group and poor lipophilicity, and thus may have weak or no central effects when administered peripherally.
ñMS, also known as ñ-methyl-5-hydroxytryptamine (ñ-methyl-5-HT), is a substituted tryptamine derivative and the ñ-methylated analogue of serotonin (5-hydroxytryptamine or 5-HT).
The predicted log P (XLogP3) of ñMS is 0.6.
ñ-Methyltryptophan (ñMTP) and ñ-methyl-5-hydroxytryptophan (ñ-Me-5-HTP) are prodrugs of ñMS which cross the bloodâÂÂbrain barrier and thus efficiently deliver ñMS into the central nervous system. As a result, these compounds act as orally bioavailable false or substitute neurotransmitters for serotonin, and have been suggested as possible therapeutic agents in the treatment of disorders where serotonin is deficient. The O-methylated analogue of ñMS, 5-MeO-ñMT (ñ,O-dimethylserotonin; ñ,O-DMS), also readily enters the brain, and could be used for such purposes as well.
ñMS is not an explicitly nor implicitly controlled substance in Canada as of 2025.
ñMS is not scheduled at the federal level in the United States, but it could be considered an analogue of ñ-methyltryptamine (AMT), in which case, purchase, sales, or possession could be prosecuted under the Federal Analog Act.
ñMS is a Schedule I controlled substance in the state of Florida making it illegal to buy, sell, or possess in Florida.