Okay, i guess it is safe to use sp long term then 
A detailed safety assessment of a saw palmetto extract,
Andrew L. Avinsa, b, c, d, , , Stephen Bentb, c, e, Suzanne Stacconeb, Evelyn Baduaf, Amy Padulab, Harley Goldberga, John Neuhausd, Esther Hudesd, Katusto Shinoharaf, g and Christopher Kanef, g
aDivision of Research, Northern California Kaiser Permanente, United States
bGeneral Internal Medicine Section, San Francisco VA Medical Center, United States
cDepartment of Medicine, University of California, San Francisco, United States
dDepartment of Epidemiology and Biostatistics, University of California, San Francisco, United States
eOsher Center for Integrative Medicine, Department of Medicine, University of California, San Francisco, United States
fUrology Section, San Francisco VA Medical Center, United States
gDepartment of Urology, University of California, San Francisco, United States
Background
Saw palmetto is commonly used by men for lower-urinary tract symptoms. Despite its widespread use, very little is known about the potential toxicity of this dietary supplement.
Methods
The Saw palmetto for Treatment of Enlarged Prostates (STEP) study was a randomized clinical trial performed among 225 men with moderate-to-severe symptoms of benign prostatic hyperplasia, comparing a standardized extract of the saw palmetto berry (160 mg twice daily) with a placebo over a 1-year period. As part of this study, detailed data were collected on serious and non-serious adverse events, sexual functioning, and laboratory tests of blood and urine. Between-group differences were assessed with mixed-effects regression models.
Results
There were no significant differences observed between the saw palmetto and placebo-allocated participants in the risk of suffering at least one serious adverse event (5.4% vs. 9.7%, respectively; p = 0.31) or non-serious symptomatic adverse event (34.8% vs. 30.1%, p = 0.48). There were few significant between-group differences in sexual functioning or for most laboratory analyses, with only small differences observed in changes over time in total bilirubin (p = 0.001), potassium (p = 0.03), and the incidence of glycosuria (0% in the saw palmetto group vs. 3.7% in the placebo group, p = 0.05).
Conclusions
Despite careful assessment, no evidence for serious toxicity of saw palmetto was observed in this clinical trial. Given the sample size and length of this study, however, these data do not rule out potential rare adverse effects associated with the use of saw palmetto.