Written by Alexandra Papanicolaou
Benign prostatic hyperplasia (BPH) is a common ailment that impacts millions of men by causing lower urinary tract symptoms (LUTS) and increasing in prevalence as they become older  (a total of 30 percent of men over the age of 65 could be affected by LUTS). Men’s prostates grow inexorably as they age, generating troubling symptoms that prompt them to seek medical attention . In most Western countries, the use of plants and herbs (phytotherapy) for the alleviation of lower urinary tract symptoms associated with BPH is common and has been steadily increasing. One of numerous phytotherapeutic drugs available for the treatment of BPH is an extract from the berry of the American saw palmetto, Serenoa repens (SR), also known by its botanical name of Sabal serrulatum ,.
The causes of prostate enlargement are still not fully understood. In general, it is believed that the testosterone metabolite dihydrotestosterone (DHT) is a key modulator of prostatic development. Through the activity of the enzyme 5-reductase, DHT is produced from testosterone in particular tissues, including the prostate gland. DHT promotes the transcription of androgen-regulated genes that are mitogenic to both stromal and epithelial cells by binding to nuclear androgen receptors.
Generally, there are several treatment choices based on the disease’s severity. There are medications, surgeries, and herbal treatments available. Alpha-blockers relax the smooth muscles of the prostate and bladder neck, enabling urine to flow more freely and reducing the blockage of urine flow. In addition, alpha-blockers act rapidly and have little effect on prostate enlargement, making them a good first-line therapeutic option for men with mild to moderate symptoms.
Herbal medicines can be used to treat BPH in mild to moderate symptoms. Hence, due to the drug-related effects associated with alpha-blockers and 5-ARIs (5-ARIs, also known as DHT blockers), there is continued interest in the use of saw palmetto extract (SPE) in patients with BPH . Serenoa repens was designated as a starting material for herbal medicines in the category of well-established use for the symptomatic treatment of BPH based on a significant amount of verifiable scientific data. More precisely, when compared to the control group, therapy with this extract led to a considerable improvement in inflammation, according to the findings of an important study .
SPE’s precise mechanisms of action in treating LUTS caused by BPH are unknown, although studies suggest that they involve anti-androgenic, pro-apoptotic, and anti inflammatory activities. Regarding the anti-androgenic mechanism, SPE non selectively inhibits both the type I and type II isoenzymes of 5′-reductase. According to a 3-month randomized research, Permixon (320 mg/day) significantly reduced DHT and elevated testosterone in the periurethral region of the prostate in BPH patients, which is consistent with in vitro studies and suggests that SPE inhibits 5′-reductase in vivo. Additionally, preclinical and clinical research suggested that SPE, in particular Permixon, may successfully treat BPH symptoms through anti inflammatory and proapoptotic pathways .
The bioactive Serenoa repens components, which include fatty acids and phytosterols, are what allow it to have all these effects. The fruit of saw palmetto typically contains 70–90percent free fatty acids of caprylic, capric, lauric, myristic, palmitic, stearic, oleic, linoleic, and linolenic acid. Depending on the extraction process, plant source, and added substances, different saw palmetto products have different chemical make-ups. For instance, in 14 SPE extracts that are commercially available for the treatment of LUTS, the amount of total free fatty acids was discovered to range from 40.7 to 80.7 percent. Additionally, it was discovered that the amounts of free fatty acids and phytosterols varied according on the kind of supplement, such as liquid, powder, dried berry, or tincture.
The primary fatty acids in SPE exhibited 1-adrenergic receptor-binding activity as well as inhibitory effects on 5-reductase, indicating that fatty acids in SPE help to relieve BPH symptoms by causing muscle tone to relax and by inhibiting the metabolism of testosterone. Nevertheless, different studies revealed that the inhibitory action of various fatty acids varies. Lauric acid and myristic acid, in particular, were shown to be the most efficient in inhibiting the 5′-reductase found in prostatic epithelium and stroma homogenates, while oleic acid and palmitic acids had essentially no inhibitory effect. In addition to fatty acids, studies have shown that phytosterols—even though they constitute a small portion of SPE, they might help treat BPH because of their anti-inflammatory and cholesterol-lowering properties .
In the EU, serenoa repens is approved for the symptomatic management of BPH under wellestablished usage criteria. Oral administration of 320 mg once per day or 160 mg twice per day is advised (possibility for long-term use) . However, as most of drugs, serenoa repens can also have some side effects, and its adverse effects are mild and similar to placebo-related side effects. Abdominal pain, diarrhea, nausea, exhaustion, headaches, decreased libido, and rhinitis are the most often reported side effects. Although individual case reports and data from spontaneous reporting schemes have documented more severe adverse events, such as death and brain hemorrhage, causality is uncertain given that the majority of users seem to handle Serenoa repens well and that substantial adverse events are not associated to it . Consequently, it is safe to treat benign prostatic hyperplasia with herbal remedies derived from Serenoa repens, although certain studies have found that it can have a placebo-like effect.
1. Agbabiaka TB, Pittler MH, Wider B, Ernst E. Serenoa repens (saw palmetto): a systematic review of adverse events. Drug Saf. 2009;32(8):637-647. doi:10.2165/00002018-200932080-00003
2. Blair HA. Hexanic Extract of Serenoa repens (Permixon®): A Review in Symptomatic Benign Prostatic Hyperplasia [published correction appears in Drugs Aging. 2022 Apr;39(4):313]. Drugs Aging. 2022;39(3):235-243. doi:10.1007/s40266-022-00924-3
3. Chughtai, B., Forde, J., Thomas, D. et al. Benign prostatic hyperplasia. Nat Rev Dis Primers 2, 16031 (2016). https://doi.org/10.1038/nrdp.2016.31
4. Csikós E, Horváth A, Ács K, et al. Treatment of Benign Prostatic Hyperplasia by Natural Drugs. Molecules. 2021;26(23):7141. Published 2021 Nov 25. doi:10.3390/molecules26237141
5. Kwon Y. Use of saw palmetto (Serenoa repens) extract for benign prostatic hyperplasia. Food Sci Biotechnol. 2019;28(6):1599-1606. Published 2019 Apr 17. doi:10.1007/s10068-019-00605-9
6. Lloyd GL, Marks JM, Ricke WA. Benign Prostatic Hyperplasia and Lower Urinary Tract Symptoms: What Is the Role and Significance of Inflammation?. Curr Urol Rep. 2019;20(9):54. Published 2019 Aug 3. doi:10.1007/s11934-019-0917-1
7. Tacklind J, Macdonald R, Rutks I, Stanke JU, Wilt TJ. Serenoa repens for benign prostatic hyperplasia. Cochrane Database Syst Rev. 2012;12(12):CD001423. Published 2012 Dec 12. doi:10.1002/14651858.CD001423.pub3