Proof-of-concept Study to Evaluate the Safety and Efficacy of Tryptophan in Patients with BPH.

Inclusion Criteria: * Written informed consent; * Male patients with BPH for which tamsulosin is the therapeutic option per SoC; * Aged ≥50 and less than 75 years old; * With prostate volume ≥30 cm3 by TRUS; * Diagnosed with LUTS defined by a stable IPSS total score ≥13 points. Exclusion Criteria: * Patients with post-void bladder residual volume ≥250 ml; * Patients with intravesical obstruction from any cause other than BPH; * History of any procedure considered an intervention for BPH; * Patients with active urinary tract infection; * History of recurrent urinary tract infections; * Current prostatitis or diagnosis of chronic prostatitis; * History of prostate or invasive bladder cancer; * Use of 5 α-reductase inhibitors within 6 months; * Phytotherapy within 2 weeks before entry; * Use of serotonin reuptake inhibitors or monoamine oxidase inhibitors; * Patients with acute or chronic kidney failure; * Patients with diagnosed or suspicion of intolerance to lactose; * Patients submitted to general anesthesia in the past 4 weeks; * Known intellectual disability that may hampers giving informed consent and would make the patient inappropriate for entry into this study, in the judgment of the investigator.