Saw palmetto is a small palm plant. The plant’s seeds are what contain the medicinal properties. The seeds are turned into an extract. This extract can be used to treat irritable bladder and other urinary tract issues. Additionally, the extract can also treat respiratory issues such as a persistent cough. Saw palmetto can be found in extract or capsule form.
The medicinal parts are the partially dried ripe fruit, the ripe fresh fruit, and the ripe dried fruit.
Flower and Fruit
The inconspicuous cream flowers are in short, densely pubescent, paniculately branched inflorescences. The fruit is deep purple to almost black. It is an ovate, 3 cm long, 1-seeded berry. It has a hard but fragile pericarp that covers a pale brown, spongy pulp. The endocarp is thin and papery. The fruit is slightly wrinkled, 1.25 to 2.5 cm long and 1.25 cm in diameter. The hard seed is pale brown, oval or globular, and has a hilum near the base. The whole panicle can weigh up to 4 kg.
Leaves, Stem, and Root
The plant is a bushy palm with a maximum height of 6 m. The large, yellow-green leaves have up to 20 segments and form a crown.
The taste of the seeds is soapy and unpleasant.
The plant is indigenous to the coastal regions of the southern states of the U.S., from South Carolina to Florida and southern California.
Sabal, Shrub Palmetto
Actions & Pharmacology
Steroids: Sterols, including beta-sitosterol, beta-sitosterol-3-O-glucosides, beta-sitosterol-3-O-diglucoside, beta-sitosterol-fatty acid esters and their glucosides, for example beta-sitosterol-3-O-myristate, beta-sitosterol-3-O-(6-O-myristyl-beta-glucosides)
Flavonoids: including isoquercitrin, kaempferol-3-O-glucosides, rhoifolin
Water-soluble polysaccharides (galactoarabane with uronic acid)
Fatty oil: free fatty acids
The lipophilic components (fatty oil with phytosterines) can be found in ethanolic and hexane extracts. The anti-exudative components (polysaccharides) are found in aqueous extracts. Ethanolic extracts contain both component groups.
In human studies, Saw Plametto's mechanism of action in the treatment of benign prostate hyperplasia (BPH) may have multiple sites of action and involves antiandrogenic, antiestrogenic, and estrogenic properties. Saw Plametto has been historically used as a treatment for prostate enlargement and chronic cystitis as well as a mild diuretic.
The lipophilic extract of the herb inhibits binding of dihydrotestosterone (DHT) to the cytosolic androgenic receptor and alpha1-adrenoceptor in the prostate, thus preventing accumulation of the steroid, which may lead to prostate hyperplasia (Carilla, 1984; Goepel, 1999). Antiandrogenic effects of the lipophilic extract also consist of 5-alpha-reductase and 3- ketosteroid reductase inhibition. These enzymes are responsible for the conversion of testosterone to DHT and for conversion of DHT to an androgen compound, respectively (Sultan, 1984).
The herb lowers cytosol and nuclear receptor values for estrogen, which result in an antiestrogen effect since progesterone receptor content is linked to estrogenic activity. Antiestrogenic agents inhibit stromatic prostate mass growth in patients with benign prostate hypertrophy (DiSilverio, 1992). There is also some evidence with inhibition of several steps involved in prolactin receptor signal transduction in ovary cells (Vacher, 1995).
The hexane extracts of the herb have demonstrated anti-inflammatory activity (Champault, 1984). Inhibition of the synthesis of arachidonic acid inflammatory metabolites, through a double blocking of cyclooxygenase and 5-lipoxygenase pathways, results in anti-inflammatory properties. (Breu, 1992). The drug also contains antispasmodic properties by inhibiting calcium influx and activation of the sodium/calcium ion exchanger. Induction of protein synthesis plays a role in the antispasmotic effect with cyclic AMP as a possible mediator. Extracts of the drug may also antagonize the contracting effect of acetylcholine on urinary bladders (Gutierrez, 1996).
Benign Prostatic Hyperplasia
No benefit of Saw Palmetto extract over placebo for benign prostatic hyperplasia (BPH) was found in a 12-month, randomized, and double-blind trial. The Saw Palmetto failed to improve symptoms or objective measures of BPH in the trial, in which 225 men (all over age 49) with moderate-to-severe BPH symptoms where randomly assigned to placebo or Saw Palmetto extract (160 mg twice daily). During the study, no significant difference between the herb and placebo was identified in change of scores on the American Urological Association Symptom Index, which is a validated, seven-item, self-administered questionnaire that measures symptoms relating to urinary obstruction. Significant differences were also not identified between the two groups in terms of maximal urinary flow rate, residual volume after voiding, prostate size, or serum prostate-specific antigen (PSA) levels. Quality of life, side effects, and laboratory values remained similar. While the extract of Saw Palmetto used in the study was similar to that of products commonly purchased by the more than 2 million men in the United States who use the herb for BPH, the authors note the possibility that the level of active ingredient in the herb may have been too low to produce a measurable effect (Bent, 2006).
A similar view was articulated in an accompanying editorial, “Proven and Unproven Therapy for Benign Prostatic Hyperplasia,” which pointed out that different dosages or preparations may account for the negative results, and that more of such rigorous, placebo-controlled studies are needed before conclusive statements can be made regarding Saw Palmetto's potential for alleviating BPH symptoms. Long-term effectiveness and safety data also must be explored, the authors note (DiPaola, 2006).
A large review of evidence, also published in 2006, concludes that while recent well-designed trials don't illustrate significant benefits of Saw Palmetto for BPH, the weight of data nevertheless points to efficacy of this herb for this indication. Findings of most published trials are limited; most have been brief (just one to six months), involved a small number of participants, and failed to employ standardized outcome measurements (Ulbricht, 2006).
In one study involved 685 patients with severe BPH, the efficacy of Permixon®, a Saw Palmetto extract, was compared to that of tamsulosin. In the 12-month, double-blind, randomized study, subjects were assigned to receive Permixon (320 mg/day) or tamsulosin (0.4 mg/day). Permixon was found to be slightly superior to tamsulosin in reducing low urinary tract symptoms (Debruyne et al, 2004).
A prospective, single-blind, randomized, and parallel 12-month trial in 64 men (mean age 43.2) comparing the effectiveness of Saw Palmetto (325 mg daily) with Finasteride 5 mg daily in the treatment of category 111 prostatitis and chronic pelvic pain syndrome found no appreciable long-term improvement in those taking the herb (n=32). The Finasteride group (n=32), in contrast, experienced significant and ongoing relief for all measurements except urination. A placebo-controlled trial of Saw Palmetto for these indications is merited, the authors conclude (Kaplan, 2004).
In an earlier review, published in 2000, a systematic analysis of 18 randomized clinical trials comprising approximately 3,000 subjects conducted between 1983 and 1997 concluded that Saw Palmetto herbal combination products provided some benefit in controlling lower urinary tract symptoms and flow measures in men with BPH (Wilt et al, 2000).
In another, earlier study comparing Permixon® with tamsulosin, the lipido-sterolic extract of Serenoa repens (Permixon®) exhibited similar efficacy to alpha-blocker tamsulosin in the treatment of BPH in a 12-month, randomized, double-blind, multicenter, international trial (n=704, mean age 65.5 years). Following a 4-week placebo lead-in period, subjects were randomly assigned to oral therapy with 320 mg Serenoa repens daily or 0.4 mg tamsulosin daily for 12 months. Reductions of 4.4 in the International Prostate Symptom Score (IPSS) compared to baseline (mean IPSS=15.3 at baseline) were observed after treatment for 1 year in both groups (differences between groups were not significant). Significant differences between groups were not observed in IPS score for irritative or obstructive symptoms. Peak urinary flow was increased by 1.79 mL in subjects treated with Serenoa repens compared to a slight increase (0.22 mL) in subjects treated with tamsulosin, although this difference was not significant (Debruyne et al, 2002).
A lipido-serolic extract of Serenoa repens was effective in improving subjective and objective parameters of BPH in subjects with mild to moderate disease in an open-label study (n=75; 52 to 78 years) (Al-Shukri et al, 2000).
A combination product containing Saw Palmetto, cernitin, β-Sitosterol, and vitamin E improved subjective but not objective symptoms of BPH compared to placebo in a randomized clinical trial (n=144). Subjects were randomly assigned to receive 2 tablets of a combination product containing 286 mg of Saw Palmetto/phytosterol (Saw Palmetto standardized to 40% to 50% free fatty acids/β-sitosterol standardized to 43%), 378 mg cernitin, and 100 international units of vitamin E daily or placebo for 3 months. Improvement of 242% in daytime urinary frequency and 258% in nocturia were also observed compared to placebo over the 3-month treatment period (p=0.031 and p less than 0.001, respectively) (Pruess et al, 2001).
A fixed combination of extracts of Saw Palmetto fruit (Serenoa repens) and nettle root (Urtica dioica) (PRO 160/120) produced the same effect as the 5-alpha-reductase inhibitor finasteride in men with BPH, regardless of the baseline prostate volume. The study assessed a subgroup of men (n=431), 50 to 88 years, who participated in a 48-week randomized multicenter double-blind clinical trial (Sokeland, 2000).
Indications & Usage
Approved by Commission E:
- Irritable bladder
- Prostate complaints
This medication relieves only the difficulties associated with an enlarged prostate without reducing the enlargement.
In folk medicine, Saw Palmetto is used for inflammation of the urinary tract, bladder, testicles, and mammary glands. It has been used for nocturnal enuresis, persistent cough, eczema, and improvement of libido.
The herb is used for micturation problems and inflammation of the urinary tract.
Precautions & Adverse Reactions
Stomach complaints following intake have been observed in rare cases. Patients with hormone-dependent cancers should observe caution and speak to a physician regarding the use of Saw Palmetto because of its antiestrogenic, estrogenic, and antiandrogenic effects.
The use of Saw Palmetto during pregnancy is not recommended due to its potential hormonal effects.
The use of Saw Palmetto during breastfeeding is not recommended due to its potential hormonal effects.
Concurrent use may result in increased risk of bleeding. Clinical Management: Caution is advised if Saw Palmetto is taken with warfarin. Monitor the INR and signs and symptoms of excessive bleeding.
Hormones, Hormone-Like Drugs, or Adrenergic Drugs
Concomitant use may interfere with therapy due to the possible estrogenic, androgenic, and alpha-adrenergic blocking effects of Saw Palmetto. Clinical Management: If concomitant use cannot be avoided, monitor patient for effects and adjust dose accordingly.
The tannin content of Saw Palmetto may complex with concomitantly administered iron, resulting in nonabsorbable, insoluble complexes that may lead to adverse sequelae on blood components. Clinical Management: Until more is known, patients who need iron supplementation should be advised to separate administration times of these 2 compounds by 1 to 2 hours.
Mode of Administration
Comminuted herb and other galenic preparations for oral use.
- Capsule-80 mg, 125 mg, 160 mg, 227 mg, 250 mg, 320 mg 450 mg, 500 mg, 565 mg, 570 mg, 585 mg, 600 mg, 1000 mg
The average daily dose is 1 to 2 g of the drug or 320 mg of the lipophilic extract (hexane or ethanol 90% v/v). Dosages used in studies demonstrated efficacy at 160 mg given twice daily or 320 mg given once daily (Carraro, 1996; Gerber, 1998; Grasso, 1995).