Saw palmetto

A palm-berry extract, taken above all with an ageing prostate in mind.

People take it for

Urinary symptoms
Daytime loo trips
Hair growth
Pelvic pain

A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.

Compare saw palmetto prices per dose

What is saw palmetto?

Saw palmetto is Serenoa repens, a low-growing American palm also called the dwarf palm, and supplements are made from its berry. What they carry is the oil of the fruit: free fatty acids, lauric acid among them, together with plant sterols such as beta-sitosterol. It is sold as ground berry powder and, far more often, as an extract drawn out with a solvent and standardised so that fatty acids make up most of the weight. Of everything men take for the urinary symptoms that arrive with an enlarging prostate, this is the one taken most often.

Why do people take saw palmetto?

Urinary symptoms

The thinking. As the prostate enlarges with age it starts to obstruct and to irritate, and what a man notices is a stream that starts slowly or runs weakly, a sense of not having quite finished, and trips out of bed at night. Prostate growth is thought to be sustained by the male hormone dihydrotestosterone, and the idea is that saw palmetto’s fatty acids damp down 5-alpha-reductase, the enzyme a class of prescription prostate medicine is named after, while its sterols quieten inflammation in the gland. Men buy it over the counter for the same symptoms those medicines are prescribed for.

What research has found. Most of the large reviews here, one pooling trials in 8,564 men and another in 5,666, report urinary symptom scores and urine flow little different from a dummy capsule, at up to three times the usual dose and in trials running beyond a year. Reviews restricted to one standardised hexanic extract are the exception: they report roughly two-thirds of a night-time trip fewer and a faster stream. Set against the prescription medicines usually offered for these symptoms, pooled trials find much the same scores and much the same flow. This is one of the best-studied uses, and several reviews of trials broadly agree.

Daytime loo trips

The thinking. Plenty of the people who buy saw palmetto have never been told they have anything. They are simply aware of how often they are looking for a lavatory during the day, and of the low-grade nuisance of it. That gap is what the newest of this research was aimed at, and the thinking behind it is the same as for the fuller set of symptoms.

What research has found. One randomised trial has measured this directly, in adults over fifty in Japan who were bothered by how often they needed to go but carried no diagnosis. After twelve weeks on 320 mg a day, the bother they reported from daytime urination was lower than on a dummy capsule, and the count they kept in a urinary diary came down as well. Few studies have measured this yet, so there is little to go on either way.

Hair growth

The thinking. The second reason saw palmetto sells in Britain has nothing to do with the bladder. Male-pattern hair loss is a hormone-driven thinning, and saw palmetto is described as anti-androgenic, meaning it works against male hormone signalling, which is why it turns up so often in hair supplements, alone or blended, at doses between 100 and 320 mg. Reviewers who have gathered that literature note that most of it tested those blends, so the berry’s own share of any result is hard to pick out.

What research has found. One two-year comparison put 320 mg a day against a prescription hair medicine in 100 men with mild to moderate pattern hair loss, judging the outcome from photographs taken at the start and at the end. Just under four in ten of the men taking saw palmetto were rated as having more hair, against roughly seven in ten on the medicine, and what gains there were showed up at the top of the head rather than at the front. Very little research has measured this so far, either way.

Pelvic pain

The thinking. Some men come to saw palmetto not for their stream but for a long-running ache in the pelvis, a steady nuisance rather than a danger. It is measured in research with a questionnaire that scores the symptoms and what they cost a person day to day. The thinking is the anti-inflammatory one that runs through the rest of this page: that the berry’s sterols quieten the inflammatory signalling in and around the gland.

What research has found. One randomised trial has measured it, giving 221 men either a saw palmetto extract or a dummy capsule for twelve weeks. Scores on that questionnaire fell further on the extract, with the gap opening within a fortnight of the first dose, and about seven in ten of the men taking it were counted as responding, against a third of those on the dummy. This has barely been studied yet, so there is not much to go on.

What does saw palmetto do in the body?

Saw palmetto is not a nutrient, and the body has no job waiting for it. What the berry’s oil seems to do is interfere, in two ways at once. Its free fatty acids, lauric acid chief among them, damp down an enzyme called 5-alpha-reductase, part of the male-hormone machinery, while its plant sterols, mainly beta-sitosterol, quieten inflammation in the gland. Reviews also describe it easing the hormonal support that keeps prostate cells multiplying, and nudging those cells towards their ordinary end of life instead.

The catch is that no two extracts are alike. What comes out depends on how it is drawn out, which solvent and at what temperature, so two products from the same plant can carry different mixtures and behave differently. That is part of why the research splits as it does: the reviews reporting a difference from a dummy capsule are mostly those confined to one hexane-drawn extract, standardised to more than 80 per cent free fatty acids, while pooling every preparation together tends to wash the difference out.

What do people say about taking saw palmetto?

These are anecdotes people have shared, not evidence.

What people like

Most commonly, men start it once urinary symptoms creep in, often after a urologist suggested trying a supplement before anything stronger.
A fair number report an easier stream and less urgency, describing it as a gradual softening over months rather than anything they noticed quickly.
Several value it for leaving libido alone, having stopped a prescribed tablet that did not, and they stay on it for that reason.
A good many keep taking it for years even when unsure it does anything, describing it as cheap insurance for a gland they are watching.

Common complaints

The commonest complaint by far is noticing nothing at all: men who took it for years say their symptoms carried on as before.
Many of those posters went on to prostate surgery anyway, and several say the gland kept growing while they were taking it.
In hair-loss threads the usual complaint is a heavy shed starting within days or weeks, sometimes with an itchy, flaking scalp alongside.
A minority report something else and stop: ringing in the ears in one case, worse symptoms in another, and a sharp swing in libido.

How people take it

Most take a single 320 mg capsule of standardised extract daily, and a few split the same total across two or three doses.
A fair number take it alongside a prescribed prostate tablet rather than instead of one, and report no trouble combining the two.
Several stack it with other plant supplements aimed at the same thing, which is exactly why they cannot say which one, if any, helped.
Threads repeatedly advise giving it three to six months before judging, and a few stop it for a week before a prostate blood test.
A minority buy berries or a herbalist’s tincture instead of capsules, including one who made his own extract at home.

Read from these public discussions:

Questions about Saw Palmetto (Patient.info, 2018)
Does Saw Palmetto really work (Patient.info, 2015)
Saw Palmetto (Patient.info, 2018)
Do you take a natural supplement to help manage your BPH? Does anything really work for you? (Patient.info, 2017)
Massive shedding after saw palmetto? (HairLossTalk, 2015)
Shedding after taking Saw Palmetto (Bald Truth Talk, 2017)

What forms of saw palmetto are there?

Form	What’s different	Per serving, on products we list
Extract (85–95% fatty acids)	The berry’s oil drawn out with a solvent, then standardised so fatty acids are 85 to 95 per cent.	100 mg to 300 mg
Berry powder	The whole dried berry ground into a powder, with nothing concentrated or standardised out of it.	900 mg

What else is worth knowing about saw palmetto?

Trials report few unwanted effects: pooled across twelve of them in 2,399 men, the rate matched that on a dummy capsule, and withdrawals ran at about one in ten in both groups.
Men often ask whether a prostate supplement will affect sex. A review gathering twenty papers found sexual function scores no different from a dummy capsule, and no different from a prescription medicine either.
Almost every trial used 320 mg a day of a standardised extract, over periods from a few weeks to about a year and a half. Labels give the amount per serving, which may be more than one capsule.
Almost everyone in this research was a man over fifty who already had symptoms: the average age across one large pooled review was 64, with moderately troublesome scores at the start.

If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.

The research behind this page (18 studies)

How much does saw palmetto cost?

That depends on the form and the pack, so we work out the price of the same dose of every saw palmetto product we can find and rank them.

Compare saw palmetto prices per dose