What Are Saw Palmetto and Nettle Root?

What saw palmetto is

Saw palmetto, botanically Serenoa repens, is a low growing palm of the palm family (Arecaceae). It is native to the Atlantic and Gulf coastal plains of the south-eastern United States, where it grows in large stands in sandy pine woods and coastal flatlands from South Carolina through Florida and west to Louisiana. Its stem mostly creeps along the ground, and its fan shaped leaves reach one to two metres in height. The name comes from the small saw-like teeth along the edges of the leaf stalks.

The part used is the ripe fruit. The fruits are olive sized, single seeded fleshy drupes that turn dark purple to black when ripe; they are gathered in autumn and dried. For the indigenous peoples of North America the plant has been a source of food for centuries: the fruits were eaten fresh or dried, and the leaves were used for weaving and roofing.

A confusion arising from similar names is worth clearing up at the outset: saw palmetto is a different plant from the oil palm that yields palm oil and from the date palm. Palm oil comes from the West African oil palm (Elaeis guineensis) and dates from the date palm (Phoenix dactylifera); all three belong to the palm family, but they are separate genera and their compositions are not alike.

What nettle is

Nettle, botanically Urtica dioica, is a perennial of the nettle family (Urticaceae). It is common in the temperate regions of Europe, Asia and North America, on moist nitrogen rich soils, along roads and streams; it grows wild in almost every region of Anatolia. Its common name, stinging nettle, comes from the hollow hairs on its leaves and stems: when touched, these hairs break and release substances such as histamine, acetylcholine and serotonin (and a small amount of formic acid), which leave a burning sensation on the skin. Drying or cooking renders these hairs harmless.

The two different parts of the nettle plant are two different products. The leaf has been eaten in Anatolian cooking for centuries as soup, pastry filling and a cooked green; it is also infused as tea and is regarded as a leafy green rich in iron, calcium and vitamin K. The root and rhizome, on the other hand, are a separate raw material in the supplement field; they are dug up in autumn or early spring, washed, dried and made into extract. This is why it matters to check which part is used when reading a label: leaf extract and root extract do not carry the same compounds.

Marker compounds

A notable share of the dry weight of the saw palmetto fruit, roughly one tenth or a little more, is oil. Most of that oil consists of free fatty acids: lauric, oleic, myristic, palmitic and linoleic acid are the most abundant. Alongside them are phytosterols (beta-sitosterol, campesterol, stigmasterol), fatty acid esters, flavonoids and polysaccharides. In supplement products the fruit is mostly used as a lipophilic extract in which the fat soluble components are enriched; the phrase "85 to 95 percent fatty acids and sterols" often seen on labels is the standardisation measure of that extract. Because the extraction method (ethanol, hexane or supercritical carbon dioxide) changes the compound profile, products from different brands do not carry the same compounds in the same amounts.

The marker compounds of nettle root are different. The root contains lignans (secoisolariciresinol and its derivatives), beta-sitosterol and its glycosides, coumarins such as scopoletin, polysaccharides and a lectin known as Urtica dioica agglutinin. The leaf, by contrast, is rich in chlorophyll, flavonoids, minerals and carotenoids. In the European Pharmacopoeia, saw palmetto fruit and nettle root are raw materials defined under separate monographs, with their quality criteria laid down.

Topics studied in research

In the scientific literature the two plants are mostly examined under the heading of lower urinary tract symptoms, and frequently together. Laboratory studies investigate which compounds of the fruit extract interact with which cellular pathways; the enzymes involved in hormone conversion, smooth muscle tissue and inflammation markers are the most studied subjects. Studies on nettle root examine the relationship of the lignans with hormone carrier proteins, the interaction of the lectin with growth factor receptors and immune cells, and the effect of the polysaccharides on immune cells, in cell culture and animal models.

The results of studies in humans are not uniform. Small, short term studies and large, placebo controlled studies have reported different results; because the type of extract, the level of standardisation, the daily amount and the length of follow-up vary from study to study, comparison is difficult. The measures used differ as well: some studies rely on symptom scores, some on urine flow measurements, some on quality of life questionnaires. For these reasons scientific bodies still regard the field as one under continuing research, and it would be wrong to draw a firm conclusion from a single study.

Use in food and supplements

In its native range the saw palmetto fruit was eaten by indigenous peoples; today the harvest goes largely to extract production, and on international markets the fruit is found as dried fruit powder, capsules and standardised lipophilic extract. Nettle leaf is offered as food and tea, and the root as extract, capsules and drops. In Türkiye both plants are largely sold in the food supplement category, with the ingredient name, the plant part used and the amount declared on the label; the form and quantity in a given product can be read there.

Saw palmetto fruit and nettle root are widely used around the world by men to support prostate and lower urinary tract health, and research in this area is continuing. When reading a label, checking that the Latin name, the plant part used and the type of extract are all stated is the most reliable way to understand what a product contains.

Points to keep in mind

Symptoms should be assessed first. Complaints such as getting up at night to pass urine, a weakened urine stream, frequent urination or blood in the urine can arise from very different causes. Anyone with these complaints should see a physician and have the necessary assessment before starting any supplement; the screening and assessment process is described in the article on prostate cancer.

Drug interactions. For saw palmetto there are isolated case reports of increased bleeding tendency, which is why care is needed in people taking anticoagulant or antiplatelet medicines (blood thinners) and before surgery; use together with hormone containing medicines also requires assessment by a physician. For nettle, possible interactions with blood glucose lowering medicines, blood pressure medicines and diuretics have been reported; these reports relate mainly to the leaf and aerial parts, and although no confirmed interaction is on record for the root extract, the same precaution is appropriate. Anyone taking regular medication should consult their physician or pharmacist before starting any supplement. If surgery is planned, all supplements in use should be reported to the surgical team.

Laboratory tests. Whether saw palmetto affects the measurement of prostate specific antigen (PSA) has been investigated; large controlled studies found no meaningful change at usual amounts. Anyone about to have a PSA test should tell their physician about all supplements they use, so that the result can be interpreted correctly.

Reported undesirable effects. Stomach discomfort, nausea and headache have been reported for saw palmetto, and digestive complaints and, rarely, allergic skin reactions for nettle root. Contact with fresh nettle causes burning and redness of the skin; dried and processed products do not have this effect.

Special situations. Use during pregnancy and breastfeeding, in children and in people with a long standing illness requires assessment by a physician. People with a diagnosed health condition should consult their physician before use; for questions about products, you may consult your pharmacist.

This page is prepared for general information; please consult your physician for diagnosis and treatment, and your pharmacist for questions about medicines.

Frequently asked questions

Is saw palmetto the same thing as palm oil or dates?

No. Saw palmetto is the species Serenoa repens, and the part used is its fruit. Palm oil comes from the West African oil palm (Elaeis guineensis) and dates from the date palm (Phoenix dactylifera). All three belong to the palm family, but they are separate genera and their compositions are not alike.

Are nettle leaf and nettle root the same product?

No. The leaf is eaten as food and infused as tea; it is rich in chlorophyll, flavonoids and minerals. The root and rhizome carry lignans, sterols, polysaccharides and a lectin, and are extracted as a separate raw material in the supplement field. The label states which part is used.

What does "85 to 95 percent fatty acids and sterols" on a label mean?

It is the standardisation measure of the lipophilic extract in which the fat soluble components of the saw palmetto fruit are enriched: it shows that the extract contains total fatty acids (free and esterified forms together) in that proportion by weight, along with a small amount of phytosterols. Dried fruit powder often carries no such standardisation, and the extraction method also changes the compound profile.

Does saw palmetto affect the PSA test?

It has been investigated as a theoretical concern; large placebo controlled studies have reported that saw palmetto extract at usual amounts does not meaningfully change PSA levels. Even so, anyone about to have a PSA test should tell their physician about all supplements and medicines they use, so that the result can be interpreted correctly.

Do dried nettle products sting as well?

No. The stinging comes from histamine, acetylcholine, serotonin and similar substances released when the hollow hairs on the leaves and stems of the fresh plant break. Drying, cooking and extraction render these hairs harmless; the root does not carry them in the first place.

Should a physician be consulted before using saw palmetto or nettle root?

Anyone with complaints such as getting up at night to pass urine, a weakened stream or blood in the urine should first see a physician and be assessed. People on regular medication, those with a long standing illness, pregnant or breastfeeding women and children should have the decision assessed by a physician. If surgery is planned, the supplements in use should be reported to the surgical team.

Aymed İlaç Sanayi manufactures licensed human medicinal products in urology and nephrology. This page does not offer diagnosis or treatment advice; it is intended as general health information.