Written by Alejandro Andión
Serenoa is a monotypic genus with a single species: Serenoa repens, belonging to the palm family (Arecaceae). (1) It is endemic to the subtropical and tropical Southeastern United States, most commonly along the south Atlantic and Gulf Coastal plains and sand hills. It grows in clumps or dense thickets in sandy coastal areas, and as undergrowth in pine woods or hardwood hammocks. (2)
Erect stems or trunks are rarely produced but are found in some populations. It is a hardy plant; extremely slow-growing, and long-lived, with some plants (especially in Florida) possibly being as old as 500–700 years. (2)
Saw palmetto is a fan palm, with the leaves that have a bare petiole terminating in a rounded fan of about 20 leaflets. The petiole is armed with fine, sharp teeth or spines that give the species its common name. The teeth or spines are easily capable of breaking the skin, and protection should be worn when working around a saw palmetto. The leaves are light green inland, and silvery-white in coastal regions. The leaves are 1–2 m in length, the leaflets 50–100 cm long. They are similar to the leaves of the palmettos of genus Sabal. (2)
The flowers are yellowish-white, about 5 mm across, produced in dense compound panicles up to 60 cm long. (2)
The fruit is a large reddish-black drupe and is an important food source for wildlife and historically for humans. (2)
It has a very outstanding resistance to extreme weather conditions: cyclones, wave splashes, drought, heat waves, frosts and are even capable of surviving forest fires. Although it can live in different types of land, in most cases they are sandy or calcareous soils. The climate of the southeaster United States is humid subtropical with long, hot summers and short, mild winters. But cold waves can come from the north and cause frost that the palm tree resists. (1)
The generic name honours American botanist Sereno Watson. (2)
Saw palmetto fibers have been found among materials from indigenous people as far north as Wisconsin and New York, strongly suggesting this material was widely traded prior to European contact. The leaves are used for thatching by several indigenous groups, so commonly that a location in Alachua County, Florida, is named Kanapaha (“palm house”). (2)
RELEVANT STUDIES CARRIED OUT IN RECENT YEARS. (3)
There are several studies that suggest that the plant is effective for the treatment of prostate hyperplasia and its symptoms.
Some research suggests that saw palmetto can support prostate health and help prevent issues such as BPH and prostate cancer. (4)
Other human and animal studies also indicate that this supplement may reduce urinary symptoms and inflammation related to BPH. (5, 6)
What’s more, a 15-year study in 30 men concluded that taking 320 mg of saw palmetto extract daily may help prevent the progression of BPH. (7)
Prostatic hyperplasia is a condition that causes enlargement of the prostate gland resulting in decreased urine flow, which is the most annoying symptom that patients with this condition usually suffer from.
In one small 12-week study, men who took 1,000 mg daily of saw palmetto oil enriched with beta-sitosterol, a compound found naturally in many plants, experienced significant improvements in BPH symptoms compared with those who took unenriched saw palmetto oil. (8)
Similarly, a 24-week study in 354 men found that taking 320 mg of saw palmetto decreased symptoms of BPH and improved urinary flow, quality of life, and sexual function compared with a placebo. (5)
Some recent studies show that the use of this plant also seems to have beneficial effects against hair loss.
According to one study, saw palmetto may help block the activity of 5-alpha reductase, an enzyme that converts testosterone into another sex hormone called dihydrotestosterone (DHT) that is linked to hair loss. (9)
Saw palmetto may also prevent hair loss by reducing the uptake of DHT in your hair follicles, which decreases DHT’s ability to bind to specific hormone receptors. (4)
One review of 7 studies found that oral and topical supplements containing saw palmetto improved hair quality by 60%, raised total hair count by 27%, and increased hair density in 83% of people with hair loss. (10)
Even though some study results suggest that saw palmetto may have beneficial effects on hair growth, more research is needed.
USE OF SAW PALMETTO (SERENOA REPENS) EXTRACT FOR BENIGN PROSTATIC HYPERPLASIA. (11)
Benign prostatic hyperplasia (BPH) is a noncancerous growth of the prostate.
Human prostate grows with age. This continued growth (hyperplasia) can enlarge the prostate to the extent that it compresses the urethra and limits the flow of urine, causing urinary symptoms such as hesitancy, poor stream, incomplete voiding, urinary retention, and overflow incontinence as well as irritative symptoms including frequent urination, urgent urination, nocturia, and urge incontinence.
The reasons causing the prostate to enlarge are still poorly understood. In general, dihydrotestosterone (DHT), a metabolite of testosterone, is thought to be a critical mediator of prostatic growth. DHT is derived from testosterone in specific tissues including the prostate gland via the action of 5α-reductase.
It has been shown through numerous studies that the use of saw palmetto is beneficial in the treatment of prostatic hyperplasia, this is due to its components and their way of acting.
MOST RELEVANT COMPONENTS
– Fatty acids [40-80%] (Oleic acid, Lauric acid, Myristic acid, Linolenic acid, Palmitic acid, Stearic acid).
– Phytosterols [<1%] (β-Sitosterol, Campesterol, Stigmasterol)
HOW THIS COMPONENTS WORK
Fatty acids are the major constituents of SPE (Saw Palmetto Extract). The main fatty acids in SPE showed α1-adrenergic receptor-binding activity as well as inhibitory effects on 5α-reductase, suggesting that fatty acids in SPE contribute to relieving BPH symptoms via relaxation of muscle tone and inhibition of testosterone metabolism. Sub-fractionation of SPE further demonstrated that free fatty acids are largely responsible for inhibitory effects of SPE on 5α-reductase.
Thus, as described above, studies have suggested that activity of 5α-reductase and α1-adrenergic receptor-binding can be effectively inhibited by free fatty acids, particularly lauric acid, the main constituent of total fatty acids in SPE.
Studies have suggested that phytosterols may be beneficial in BPH treatment due to their anti-inflammatory and cholesterol-lowering effects. β-Sitosterol inhibited proliferation of human prostate cancer cells and growth of tumors derived from PC-3 human prostate cancer cells.
In conclusion, saw palmetto extract has therapeutic potential.
Free fatty acids such as lauric acid, the main constituents of SPE, have been shown to be effective in inhibition of 5α-reductase and phytosterol (β-sitosterol), minor constituents of SPE, was found to effectively reduce prostatic inflammation.
HOW TO TAKE SAW PALMETTO. (12)
Saw palmetto can be purchased as dried berries, powdered capsules, tablets, liquid tinctures, and liposterolic extracts. The product label should indicate that contents are standardized and contain 85% to 95% fatty acids and sterols.
HOW TO TAKE IT
– Liposterolic extract in capsules. One studied dosage for early stages of BPH (Benign Prostatic Hyperplasia) is 160 mg, twice a day. The supplement should be a fat-soluble saw palmetto extract that contains 85% to 95% fatty acids and sterols.
– Liquid extract. This preparation has not been tested in any studies, so its effectiveness is not known.
– Tea. Saw palmetto can be taken as a tea. But its active ingredients (fatty acids) are not soluble in water. So, tea may not be effective. It has not been tested in any studies. Capsules are recommended instead of tea.
It may take up to 8 weeks to see beneficial effects.
LONG-TERM SIDE EFFECTS. (12)
The use of herbs is a time-honoured approach to strengthening the body and treating disease. However, herbs can trigger side effects, and interact with other herbs, supplements, or medications.
Saw palmetto is generally thought to be safe when used as directed. Side effects are very rare, although headache, nausea, diarrhea, and dizziness have been reported. In at least one case, significant bleeding during surgery was attributed to saw palmetto. There have been two reports of liver damage and one report of pancreas damage in people who took saw palmetto. But there is not enough information to know if saw palmetto was the cause of these effects.
Saw palmetto may have effects similar to some hormones and should not be used in pregnant or nursing women, or women who have had or are at risk for hormone-related cancers.
Saw palmetto may interfere with the absorption of iron.
Because saw palmetto may work similarly to finasteride (Proscar), you should not use this herb in combination with finasteride, or other medications used to treat BPH, unless directed to by your physician.
Antiplatelet and anticoagulant drugs (blood-thinners)
Saw palmetto may affect the blood’s ability to clot, and could interfere with blood-thinning drugs, including:
– Warfarin (Coumadin)
– Clopidogrel (Plavix)
Oral contraceptives and hormone replacement therapy
Saw palmetto may reduce the number of estrogen and androgen receptors, and thus have hormone-like effects. It may make oral contraceptives less effective, raising the risk of unplanned pregnancy.
1. Wikipedia in Spanish. (June 20, 2022). Uncaria Tomentosa https://en.wikipedia.org/wiki/Uncaria_tomentosa
2. Wikipedia in English. (May 17, 2022). Uncaria Tomentosa https://en.wikipedia.org/wiki/Uncaria_tomentosa
3. Rachel Link, MS, RD – Medically reviewed by Jillian Kubala, MS, RD. (December 21, 2021). 5 Promising Benefits and Uses of Saw Palmetto
4. Xu-xin Zhan, Xue-jun Shang, Yu-feng Huang. (September 21, 2015). [Application of saw palmetto fruit extract in the treatment of prostate diseases].
5. Zhangqun Ye , Jian Huang , Liqun Zhou , Shan Chen , Zengjun Wang, Lulin Ma , Dongfang Wang , Gongxian Wang , Shusheng Wang , Chaozhao Liang , Shaopeng Qiu , Xiaojian Gu , Jianhe Liu , Zhiliang Weng , Changli Wu , Qiang Wei , Liping Xie , Weizhen Wu , Yue Cheng , Jingqian Hu, Zhixian Wang , Xiaoyong Zeng. (March 14, 2019). Efficacy and Safety of Serenoa repens Extract Among Patients with Benign Prostatic Hyperplasia in China: A Multicenter, Randomized, Double-blind, Placebo-controlled Trial. https://pubmed.ncbi.nlm.nih.gov/30880074/
6. Sophie Bernichtein , Natascha Pigat, Philippe Camparo, Alain Latil, Mélanie Viltard, Gérard Friedlander, Vincent Goffin. (February 14, 2015). Anti-inflammatory properties of Lipidosterolic extract of Serenoa repens (Permixon®) in a mouse model of prostate hyperplasia. https://pubmed.ncbi.nlm.nih.gov/25683150/
7. Andrey Zinovievich Vinarov , Leonid Grigorievich Spivak , Darina Vladimirovna Platonova , Leonid Mikhailovich Rapoport , Dmitry Olegovich Korolev. (May 9, 2018). 15 years’ survey of safety and efficacy of Serenoa repens extract in benign prostatic hyperplasia patients with risk of progression.
8. H V Sudeep , Jestin V Thomas , K Shyamprasad. (July 3, 2020). A double blind, placebo-controlled randomized comparative study on the efficacy of phytosterol-enriched and conventional saw palmetto oil in mitigating benign prostate hyperplasia and androgen deficiency. https://pubmed.ncbi.nlm.nih.gov/32620155/
9. Pilar Pais, Agustí Villar, and Santiago Rull. (April 21, 2016). Determination of the potency of a novel saw palmetto supercritical CO2 extract (SPSE) for 5α-reductase isoform II inhibition using a cell-free in vitro test system. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4847595/
10. Evyatar Evron, Margit Juhasz, Arash Babadjouni, and Natasha Atanaskova Mesinkovska. (August 23, 2020). Natural Hair Supplement: Friend or Foe? Saw Palmetto, a Systematic Review in Alopecia. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7706486/
11. Youngjoo Kwon. (April 17, 2019) Use of saw palmetto (Serenoa repens) extract for benign prostatic hyperplasia. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6859144/
12. Mount Sinai. (May 14, 2017). Saw Palmetto. https://www.mountsinai.org/health-library/herb/saw-palmetto