Saw Palmetto for Benign Prostatic Hyperplasia
Saw palmetto should not be recommended for treating lower urinary tract symptoms in men with BPH, as the highest quality evidence demonstrates no benefit over placebo for symptom improvement, urinary flow rates, or prostate size reduction. 1
Evidence Against Saw Palmetto Efficacy
The most rigorous placebo-controlled trial published in the New England Journal of Medicine found that saw palmetto (160 mg twice daily for one year) showed no significant difference from placebo in:
- American Urological Association Symptom Index scores (mean difference 0.04 points) 1
- Maximal urinary flow rates (mean difference 0.43 ml/minute) 1
- Prostate size, residual urinary volume, or quality of life measures 1
- Serum PSA levels 1
The side effect profile was identical between saw palmetto and placebo groups, confirming safety but also highlighting the lack of therapeutic benefit. 1
Why Earlier Studies Appeared Positive
Earlier meta-analyses and smaller trials suggested potential benefits, but these studies were significantly compromised by:
- Methodological flaws and inadequate blinding 2
- Small patient numbers limiting statistical power 2
- Brief treatment intervals insufficient to assess true efficacy 2
- Lack of standardized extract formulations across studies 3
The profound placebo effect in BPH treatment trials (well-documented in this population) explains why uncontrolled or poorly controlled studies showed apparent improvement. 4
Guideline-Recommended Treatments Instead
The American Urological Association and European Association of Urology guidelines emphasize that treatments with a strong evidence base for clinical effectiveness should be used 5, which explicitly excludes saw palmetto based on current evidence.
For men over 50 with bothersome LUTS, evidence-based options include:
- Alpha-blockers (alfuzosin, tamsulosin) as first-line therapy for symptom relief 5
- 5-alpha reductase inhibitors (finasteride, dutasteride) for men with enlarged prostates to reduce prostate volume and prevent progression 5, 6
- Combination therapy (alpha-blocker plus 5-ARI) for patients with moderate-to-severe symptoms and prostate enlargement, which addresses both dynamic and static components of obstruction 6
Clinical Pitfall to Avoid
Do not delay evidence-based medical therapy while patients trial saw palmetto, as this allows disease progression and potential complications including acute urinary retention, which increases with age. 7 Men with moderate-to-severe BPH symptoms require medical therapy with alpha-blockers as first-line treatment, not dietary supplements. 8
The lack of PSA interference with saw palmetto 1 is irrelevant when the agent provides no therapeutic benefit for the underlying condition.