How effective are the supplements marketed for premature ejaculation?

Manufacturers claim that supplements commonly marketed for premature ejaculation (PE) work by increasing serotonin, much like selective serotonin reuptake inhibitor medications. Some research suggests that a natural compound called 5-HTP (5-hydroxy-L-tryptophan) may help raise serotonin. However, there’s little clinical evidence that supplements of 5-HTP -- typically made from the seeds of the African Griffonia plant -- can ease depression, let alone effectively treat PE. Better to pass on such supplements and focus your attention on the other treatment options.