5-Fluoro-DET, or 5-F-DET, also known as 5-fluoro-N,N-diethyltryptamine, is a tryptamine derivative related to drugs such as diethyltryptamine (DET) and 5-MeO-DET. It is known to act as an inhibitor of the enzyme myeloperoxidase, and is also thought to be an agonist at the serotonin 5-HT<sub>2A</sub> receptor.