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Swp8.0
Saw Palmetto Research
Likely helpsHigh safety
41 peer-reviewed studies
What the evidence says
Likely helps
Saw Palmetto appears to help in 5 of 7 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2005–2026 with a typical study size of 320 participants.
Based on 41 studies · 6 meta-analyses · 26 RCTs · 40,774 total participants
Confidence
High
What the studies found
5helped2unclear· 34 more without graded effect data
This systematic-review examined the effects of Saw Palmetto.
Allam AT et al. · Naunyn-Schmiedeberg's archives of pharmacology (2025)
However, study design limitations and outcome variability necessitate further rigorous, standardized research.
This review aims to offer an integrative, evidence-informed perspective on the therapeutic potential of herbal medicine for hair loss in clinical evidence.
6Concurrent prescription drugs and herbal medicine use prevalenceSystematic ReviewCited 69×2017
The prevalence of concurrent prescription drugs and HMP use among older adults is substantial and potential interactions have been reported.
Agbabiaka TB et al. · Drugs & aging (2017)
No clear effect
← WorseNo effectBetter →
Prevalence of concurrent use by older adults varied widely between 5.3 and 88.3%.
The prevalence of concurrent prescription drugs and HMP use among older adults is substantial and potential interactions have been reported.
Knowledge of the extent and manner in which older adults combine prescription drugs will aid healthcare professionals in appropriately identifying and managing patients at risk.
Serenoa repens alone provides little to no benefits for men with lower urinary tract symptoms due to benign prostatic enlargement.
Franco JV et al. · The Cochrane database of systematic reviews (2023)
Serenoa repens results in little to no difference in the quality of life at short-term follow-up (3 to 6 months; IPSS quality of life domain range 0 to 6, higher scores indicate worse quality of life; MD -0.20, 95% CI -0.40 to -0.00; I2 = 39%; 5 studies, 1001 participants; high-certainty evidence).
Serenoa repens probably results in little to no difference in adverse events (1 to 17 months; risk ratio (RR) 1.01, 95% CI 0.77 to 1.31; I2 = 18%; 12 studies, 2399 participants; moderate-certainty evidence).
Serenoa repens results in little to no difference in urologic symptoms at long-term follow-up (12 to 17 months, IPSS score, MD 0.07, 95% CI -0.75 to 0.88; I2 = 34%; 3 studies, 898 participants; high-certainty evidence).
While the significance of many interactions is uncertain, several interactions, particularly those with St John's wort, may have serious clinical consequences.
Izzo AA et al. · Drugs (2009)
Echinacea might affect the clearance of caffeine (a CYP1A2 probe) and midazolam (a CYP3A4 probe).
No interactions have been reported for saw palmetto (Serenoa repens).
Numerous interactions between herbal medicines and conventional drugs have been documented.
12Adverse events assessmentSystematic ReviewCited 53×n=26 · very small study2009
However, higher quality reporting of adverse events is essential if safety assessments are to be improved in future.
Agbabiaka TB et al. · Drug safety (2009)
Currently available data suggest that S. repens is well tolerated by most users and is not associated with serious adverse events.
The majority of adverse events are mild, infrequent and reversible, and include abdominal pain, diarrhoea, nausea and fatigue, headache, decreased libido and rhinitis.
We found no evidence for drug interactions with S. repens.
13Systematic review of saw palmetto evidenceSystematic ReviewCited 9×2006
Here presented is an evidence-based systematic review including written and statistical analysis of scientific literature, expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.
Ulbricht C et al. · Journal of the Society for Integrative Oncology (2006)
Here presented is an evidence-based systematic review including written and statistical analysis of scientific literature, expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.
14Lower urinary tract symptoms (LUTS)RCTCited 3×n=76 · small study2022
In conclusion, the present study is the first to demonstrate the potential of SPE to mitigate LUTS in adult women.
Yamada S et al. · Nutrients (2022)
The daytime frequency of urination in overactive bladder symptom score (OABSS) Q1 was also significantly improved by the SPE treatment.
A subgroup analysis revealed that SPE alleviated the symptoms of daytime frequency (CLSS Q1) and nocturia (CLSS Q2) in a subset of subjects with a CLSS Q5 score of 1 or higher.
In conclusion, the present study is the first to demonstrate the potential of SPE to mitigate LUTS in adult women.
16Urinary frequency-related quality of lifeRCTCited 2×n=34 · small study2025
The consumption of SPE improved urinary frequency-related quality of life such as bother of urinary symptoms in healthy Japanese adults (UMIN000045334).
Kimura M et al. · Nutrition and health (2025)
After SPE intervention for 12 weeks, the score of symptom bother by frequent urination during the daytime hours was significantly improved and the daytime frequency of urination assessed using the urinary log was significantly decreased.
The other outcomes were subjective urinary symptoms and urinary frequencies.
The final efficacy analysis dataset was per protocol set, and 33 participants in each group were analyzed.
17Treatment assignment blinding successRCTCited 5×n=151 · medium study2014
Blinding of treatment assignment was successful in this study.
Lee JY et al. · Journal of alternative and complementary medicine (New York, N.Y.) (2014)
Could be chance
For participants assigned to saw palmetto, 22.5%, 24.7%, and 29.8% correctly thought they were taking saw palmetto, and 37.3%, 40.0%, and 44.4% incorrectly thought they were on placebo at 24, 48, and 72 weeks, respectively.
For placebo participants, 21.8%, 27.4%, and 25.2% incorrectly thought they were on saw palmetto, and 41.6%, 39.9%, and 42.6% correctly thought they were on placebo at 24, 48, and 72 weeks, respectively.
The treatment arms did not vary with respect to the distributions of participants who guessed they were on saw palmetto (p=0.823) or placebo (p=0.893).
18Nocturnal voiding frequencyRCTCited 9×n=922 · large study2014
PRO 160/120 significantly improved nocturnal voiding frequency compared to placebo and similar to tamsulosin or finasteride.
Oelke M et al. · World journal of urology (2014)
Noticeable benefit
← WorseNo effectBetter →
Likely real
In the pooled analysis of placebo-controlled trials, nocturnal voids improved by 0.8 (29 %) with PRO 160/120 compared to 0.6 (18 %) with placebo (p = 0.015, Wilcoxon test, one-tailed).
The 69 % responder rate to PRO 160/120 was significantly superior to the placebo response (52 %; p = 0.003, χ (2)-test, two-tailed).
PRO 160/120 significantly improved nocturnal voiding frequency compared to placebo and similar to tamsulosin or finasteride.
The daily use of a proprietary saw palmetto (Serenoa repens) extract safely and effectively promotes hair growth in men and women with self-perceived thinning hair.
Ablon G · Journal of cosmetic dermatology (2026)
Noticeable benefit
← WorseNo effectBetter →
Likely real
Mean (SD) change in baseline total terminal hair count was +18.6 (29.6) with active vs. -10.1 (30.5) with placebo (p < 0.001; 283% greater improvement).
Total vellus hair count increased +6.6 (15.6) vs. -2.1 (15.7) (p < 0.05; 414% greater improvement).
Total hair density rose +25.1 (27.7) vs. -12.2 (38.8) (p < 0.001; 306% greater improvement).
20Lower urinary tract symptoms in BPHRCTn=46 · small study2024
Our findings support the efficacy of USP-verified Saw Palmetto extract in alleviating LUTS in men with BPH.
Winograd J et al. · The Canadian journal of urology (2024)
Results from 46 patients using 320 mg daily of USP-verified Saw Palmetto extract revealed significant improvements in IPSS and QoL scores at 12 weeks compared to baseline, particularly in patients with moderate symptoms.
Our findings support the efficacy of USP-verified Saw Palmetto extract in alleviating LUTS in men with BPH.
Further studies are warranted in larger, diverse cohorts over longer follow up periods.