herb · for prostate symptoms
Saw Palmetto
Meant to block the hormone that enlarges the prostate. That has not translated into results.
Say that in clinical terms
Proposed to inhibit 5-alpha-reductase and reduce inflammatory/growth signaling in prostate tissue, lowering intraprostatic DHT; this has not translated into a measurable symptom benefit in rigorous trials.
How strong is the research?
One year of saw palmetto extract (160 mg twice daily) produced no significant improvement in symptoms or objective measures (flow rate, prostate size, PSA, QoL, residual volume) vs placebo. This is the STEP trial.
4 papers read, 3 against.
Tested as: Saw palmetto (Serenoa repens) berry extract. STEP trial used 160 mg twice daily (320 mg/day); CAMUS trial dose-escalated the same 320 mg/day extract to 640 mg/day then 960 mg/day (3x usual dose) over 72 weeks. Neither trial used the hexane-extracted lipidosterolic preparation (Permixon) specifically, and the Cochrane review pooled 27 trials of varying extracts/solvents.
Who was studied: Men over 45 with moderate to severe urinary symptoms from an enlarged prostate.
How much to take
320–960 mg
Before you take it
- No Tolerable Upper Intake Level (UL) has been established by NIH ODS for saw palmetto (Serenoa repens) — it is a botanical extract, not a nutrient with a defined UL.
- Contraindicated in pregnancy and lactation: 5-alpha reductase (5-AR) inhibition may disrupt androgen-dependent fetal development; saw palmetto is effectively Category X in pregnancy.
- Case reports document increased bleeding risk in patients co-administering anticoagulants (warfarin) or antiplatelet agents; the proposed mechanism is antiplatelet activity from fatty acid constituents. Clinical significance is debated but co-administration warrants caution.
- May reduce efficacy of exogenous hormonal therapies — including oral contraceptives, testosterone replacement, HRT, and co-prescribed anti-androgens (spironolactone, cyproterone) — by competing for the same androgenic pathway.
- 5-AR inhibition suppresses PSA values; men taking saw palmetto may show false-low PSA results, potentially obscuring early prostate cancer detection.
- Rare case reports of cholestatic hepatitis have been associated with saw palmetto; the causal relationship is unconfirmed but hepatotoxicity is a recognized rare adverse event.
- Most common adverse effects are GI-related (nausea, diarrhea, constipation, abdominal discomfort); generally mild and transient at standard doses.
- In vitro inhibition of CYP2C9, CYP2C19, and CYP3A4 has been observed at supratherapeutic concentrations; no clinically confirmed pharmacokinetic drug-drug interactions have been demonstrated at standard doses (160–320 mg/day).
When to take it
Best taken: with food