Saw Palmetto and Reduced Prostate Volume

Research synthesisLow evidenceSmall effect3 studies · 2 beneficial · 1 neutral · 0 harmful

Across 3 studies, 2 reported small beneficial effects of saw palmetto on reducing prostate volume, while 1 high-quality RCT found no significant effect. The most-studied dose was 320 mg daily in men with benign prostatic hyperplasia, with effects typically observed at 6 months. The evidence base is small and inconsistent.

Effective dose range: 320 mg daily
Studied populations: men with benign prostatic hyperplasia (BPH)

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. The highest-quality study (RCT) found no significant effect on prostate volume, while lower-quality studies (meta-analysis and observational) reported small benefits — results are inconsistent.

Generated Jul 11, 2026

Doses used in studies

mg/day: 320 (median 320, IQR 320–320) — 2 studies

Time to effect

Median: 6 months · IQR 5.8 months–94.3 months · Range 5.6 months–182.5 months — Reported in 3 of 3 studies

Safety in these studies

decreased libidoIncreased riskOR = 5.40; 95% CI [1.17, 24.87]
Serenoa repens was well tolerated compared with tamsulosin especially in ejaculation disorders and decreased libido (OR = 5.40; 95% CI [1.17, 24.87]; p = 0.03)
from: Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperpla
ejaculation disordersIncreased riskOR = 12.56, 95% CI [3.83, 41.18]
Serenoa repens was well tolerated compared with tamsulosin especially in ejaculation disorders (odds ratio [OR] = 12.56, 95% CI [3.83, 41.18], p < 0.0001)
from: Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperpla
Overall tolerabilityReported
The Serenoa repens extract was effective, safe, well-tolerated, and clinically and statistically superior to placebo in the target LUTS/BPH population.
from: Efficacy and Safety of Serenoa repens Extract Among Patients with Benign Prostatic Hyperpl
Overall tolerabilityReported
Serenoa repens was well tolerated compared with tamsulosin especially in ejaculation disorders and decreased libido.
from: Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperpla
Overall tolerabilityReported
the patients had no adverse events related to the study drug, including prostate cancer
from: 15 years' survey of safety and efficacy of Serenoa repens extract in benign prostatic hype
adverse eventsReported2 (1.18%) of 169 patients in the placebo group and 3 (1.89) of 159 patients in the Serenoa repens extract group experienced 1 or more adverse events
Two (1.18%) of 169 patients in the placebo group and 3 (1.89) of 159 patients in the Serenoa repens extract group experienced 1 or more adverse events.
from: Efficacy and Safety of Serenoa repens Extract Among Patients with Benign Prostatic Hyperpl

3 of 3 papers

Efficacy and Safety of Serenoa repens Extract Among Patients with Benign Prostatic Hyperplasia in China: A Multicenter, Randomized, Double-blind, Placebo-controlled Trial.
- 2019-03-14
- RCT · n = 354
- Urology 129
- - Zhangqun Ye
  - Jian Huang
  - Liqun Zhou
  - Shan Chen
  - Zengjun Wang
  - Lulin Ma
  - Dongfang Wang
  - Gongxian Wang
  - Shusheng Wang
  - Chaozhao Liang
  - Shaopeng Qiu
  - Xiaojian Gu
  - Jianhe Liu
  - Zhiliang Weng
  - Changli Wu
  - Qiang Wei
  - Liping Xie
  - Weizhen Wu
  - Yue Cheng
  - Jingqian Hu
  - Zhixian Wang
  - Xiaoyong Zeng
- PubMed: 30880074
- DOI: 10.1016/j.urology.2019.02.030
10 Insights on
- Reduced Prostate Volume
- High evidence
- Large Human Trial
- Clinical
Secondary efficacy parameters included improvement of ... prostate volume, urinary frequency, and total prostate-specific antigen level.
Effect
Neutral
Effect size
Small
Significant
No
Dose
320 mg
Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis.
- 2020-03
- Meta-Analysis · n = 80
- American journal of men's health 14(2)
- - Tong Cai
  - Yuanshan Cui
  - Shaoxia Yu
  - Qian Li
  - Zhongbao Zhou
  - Zhenli Gao
- PubMed: 32274957
- DOI: 10.1177/1557988320905407
6 Insights on
- Reduced Prostate Volume
- High evidence
- Clinical
prostate volume (PV) (MD -0.29, 95% CI [-0.41, -0.17], p < 0.00001)
Effect
Beneficial
Effect size
Small
Significant
Yes
15 years' survey of safety and efficacy of Serenoa repens extract in benign prostatic hyperplasia patients with risk of progression.
- 2018-05-09
- Observational · n = 30
- Urologia 86(1)
- - Andrey Zinovievich Vinarov
  - Leonid Grigorievich Spivak
  - Darina Vladimirovna Platonova
  - Leonid Mikhailovich Rapoport
  - Dmitry Olegovich Korolev
- PubMed: 29741118
- DOI: 10.1177/0391560318772466
6 Insights on
- Reduced Prostate Volume
- Moderate evidence
- Clinical
The study showed an absence of progression based on both subjective (the sum of scores on the IPSS and QoL scales) and objective (prostate volume, urination rate, residual urine volume) criteria.
Effect
Beneficial
Effect size
Small
Significant
Yes
Dose
320 mg once a day

Saw Palmetto and Reduced Prostate Volume

Efficacy and Safety of Serenoa repens Extract Among Patients with Benign Prostatic Hyperplasia in China: A Multicenter, Randomized, Double-blind, Placebo-controlled Trial.

Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis.

15 years' survey of safety and efficacy of Serenoa repens extract in benign prostatic hyperplasia patients with risk of progression.