Prostate Health
Saw Palmetto vs Tamsulosin and Finasteride: What the Trials Show
Saw palmetto has tied two prescription prostate drugs in head-to-head trials and failed to beat a dummy pill in others, and both results are real. That sounds like a contradiction. It mostly is not, once you see how the drug comparisons were built, and that design detail decides what the trials can tell you about any supplement, Prostadine included.
Quick answer
- Is saw palmetto as effective as tamsulosin?
- In one 12-month trial of 704 men (Debruyne, European Urology, 2002), the saw palmetto extract Permixon matched tamsulosin on symptom scores. The trial had no placebo group, so it cannot show either one beat doing nothing.
- Does saw palmetto shrink the prostate like finasteride?
- No. In a 1,098-man trial (Carraro, The Prostate, 1996), finasteride reduced prostate volume by 18 percent, saw palmetto by 6 percent.
- Can I swap my prescription for saw palmetto?
- Not on your own. Stopping a BPH drug is a decision to make with your urologist.
Two head-to-head trials made saw palmetto look like a drug
Saw palmetto matched a prescription drug on symptom scores in two large randomized trials, one against tamsulosin and one against finasteride, and a third trial tested it added on top of tamsulosin. All three used 320 mg of saw palmetto a day. Here is what each one found.
| Trial | What was compared | Men and length | Result |
|---|---|---|---|
| Debruyne and colleagues, European Urology, 2002 | Permixon 320 mg a day vs tamsulosin 0.4 mg a day | 704 men randomized, 12 months | Symptom score fell 4.4 points in both groups; urine flow rose 1.8 vs 1.9 ml per second; ejaculation problems more frequent on tamsulosin |
| Carraro and colleagues, The Prostate, 1996 | Permixon 320 mg a day vs finasteride 5 mg a day | 1,098 men, 6 months | Symptom scores fell 37% vs 39%; finasteride shrank the prostate 18% and cut PSA 41%; saw palmetto shrank it 6% with no PSA change |
| Ryu and colleagues, Urologia Internationalis, 2015 | Tamsulosin 0.2 mg plus saw palmetto 320 mg vs tamsulosin alone | 120 men randomized, 12 months, open label | Total symptom score fell 5.8 vs 5.5, no significant difference; storage symptoms improved more with the combination (1.7 vs 0.8 points) |
Read the Carraro row twice. On symptoms the two landed within two percentage points; on the prostate itself they were far apart. The authors concluded that Permixon has "little effect on so-called androgen-dependent parameters," so whatever saw palmetto did there, it did not do it the way finasteride does.
Why "as good as a drug" is weaker than it sounds
The Debruyne and Carraro trials are weaker evidence than they look, because neither one included a placebo group. Urinary symptoms drift on their own, and men who start any daily treatment tend to feel better. When two treatments tie without a placebo arm, you cannot tell whether both worked or both rode that effect.
The placebo-controlled trials answer the question the comparisons dodge. The STEP trial (Bent and colleagues, New England Journal of Medicine, 2006) gave 225 men saw palmetto or placebo for a year and found a difference of 0.04 points on the symptom index. The 2023 Cochrane review by Franco and colleagues pooled 27 studies and 4,656 men and rated the finding high-certainty: little to no difference from placebo. Our saw palmetto research breakdown walks through those placebo trials in detail.
Two more details belong on the table. Carraro's trial ran six months, and MedlinePlus notes that finasteride may take at least six months to improve symptoms, so the drug was barely out of the gate when scoring stopped. The first author's listed affiliation was Pierre Fabre Médicament, the company that makes Permixon. That does not make the data false. It does mean you want independent replication, and the independent placebo trials are the ones that came back flat.
Where saw palmetto genuinely differs: side effects and PSA
Saw palmetto's real, trial-backed advantage over tamsulosin and finasteride is tolerability, especially on sexual side effects. In the Debruyne trial, ejaculation disorders were more frequent with tamsulosin. In the Carraro trial, men on Permixon scored better on a sexual function questionnaire and complained less of reduced libido and impotence. MedlinePlus lists erection problems, lower sex drive and ejaculation problems among finasteride's side effects, warns that tamsulosin can cause dizziness and fainting when you stand up quickly, and asks tamsulosin users to tell their doctor before any eye surgery.
PSA is the other practical difference. Finasteride cut PSA by 41 percent in the Carraro trial, while saw palmetto left it unchanged there and in the STEP trial. If you take finasteride, make sure whoever reads your PSA result knows it. With saw palmetto, those two trials give no sign that it masks the number.
What prostate guidelines actually recommend
The European Association of Urology guidelines treat saw palmetto as an option for a particular kind of patient, not as an equal to the drugs. The EAU makes a weak recommendation to offer hexane-extracted Serenoa repens to men with urinary symptoms who want to avoid adverse events, particularly sexual ones, and a strong recommendation to tell those men that the benefit may be modest. Alpha-blockers such as tamsulosin get a strong recommendation for moderate-to-severe symptoms. So do 5-alpha reductase inhibitors such as finasteride, for men whose risk of progression is higher, for example a prostate larger than 40 mL.
Notice the word hexane. The EAU guideline names one type of extract, the kind used in Permixon, not saw palmetto as a category.
What this means if you are considering Prostadine
The Permixon trials say nothing direct about Prostadine, because Prostadine's official site lists saw palmetto without a milligram amount or an extract type. Every trial above used 320 mg a day of a defined extract; a liquid blend with an undisclosed amount is a different product. (The official site pitches its saw palmetto for kidney support and antimicrobial effects anyway.) For the whole formula, see what is in each Prostadine drop. If you already take tamsulosin or finasteride, read the Prostadine side effects and interactions guide before adding anything. Our prostate supplements compared by ingredient scorecard ranks label ingredients by trial strength; beta-sitosterol has the most convincing placebo data.
One firm line. Do not stop a prescription BPH drug to try a supplement without talking to your doctor, and treat sudden trouble urinating, blood in the urine or pain as a reason to see a urologist promptly.
Weighing Prostadine as a whole, not just its saw palmetto? Read our complete verdict on the formula, the evidence and the guarantee before you decide.
Frequently asked questions
Can you take saw palmetto with tamsulosin?
One 12-month trial tested that exact combination. Ryu and colleagues (Urologia Internationalis, 2015) randomized 120 Korean men to tamsulosin alone or tamsulosin plus 320 mg of saw palmetto; drug-related side effects were reported by 16.9 percent and 20 percent respectively. It was small and open label, so ask your doctor or pharmacist before combining the two.
Does saw palmetto block DHT like finasteride?
Not in any way the trials could detect. MedlinePlus explains that finasteride blocks production of a male hormone that enlarges the prostate; in the Carraro trial saw palmetto moved neither prostate volume nor PSA the way finasteride did.
Is saw palmetto a natural alternative to Flomax?
Flomax is a brand name for tamsulosin. The one direct comparison, Debruyne 2002, found equal symptom relief over a year, but placebo-controlled trials show saw palmetto doing no better than placebo, so treat "natural Flomax" claims with caution and discuss any switch with your doctor.
Does saw palmetto affect PSA test results?
Not in the STEP or Carraro trials, where PSA stayed unchanged on saw palmetto. Tell your doctor about every supplement before a PSA test anyway.
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Nathan Cole
Nathan writes about men's health and supplements, and every article is reviewed for medical accuracy by clinical pharmacist Dr. Marcus Reed, PharmD.