SNTX-2643
SNTX-2643, formerly known as SENS-01, is an atypical serotonin reuptake inhibitor derived from Sceletium tortuosum. It is under development for the treatment of social anxiety disorder, as well as other anxiety disorders and depressive disorders. It is described as a novel/first-in-class and fast-acting anxiolytic without sedation. The drug is administered orally.
Pharmacology
SNTX-2643 acts as a selective atypical serotonin reuptake inhibitor. Specifically, it binds to an allosteric site on the serotonin transporter, rather than to the orthosteric site targeted by serotonin and classical selective serotonin reuptake inhibitors.Sceletium tortuosum acts similarly to SNTX-2643 via its primary alkaloid constituent, mesembrine, but SNTX-2643 is a synthetic derivative with improved drug-like properties. Unlike SSRIs, which typically require 4–6 weeks of administration to achieve therapeutic benefits, kanna is reported to have a rapid calming effect within 30–60 minutes of ingestion. The precise mechanism underlying these differences remains unclear but appears to involve distinct downstream kinase-mediated signaling pathways.
Development
SNTX-2643 is being developed by Sensorium Therapeutics. As of August 2025, it is undergoing phase 1 clinical trials.Although listed on Psychedelic Alpha’s drug development tracker, SNTX-2643 is not itself a psychedelic. Its inclusion reflects its action on the serotonin system rather than any psychedelic effects. The chemical structure of SNTX-2643 has not yet been publicly disclosed. However, mesembrine analogues acting on SERT with enhanced drug-like properties were patented by Sensorium Therapeutics in 2025.