Supplementation of Saw Palmetto and its Therapeutic Potential for Women and Men
Saw palmetto (Serenoa repens) has been used for years to help treat urinary tract symptoms associated with benign prostatic hyperplasia (BPH), chronic pelvic pain, hair loss and other health conditions.  The active, beneficial compounds mainly come from the berry/fruit of the saw palmetto plant, which is native to the southeastern part of the U.S. [1, 2]
Most research and clinical studies have investigated the benefits of saw palmetto for men; less is known about its use for other groups of people.  Current conventional drugs and medications for the conditions listed above have questionable efficacy and often come with side effects such as decreased libido, erectile dysfunction, and lowered semen count. [3, 4] Thus herbal extract alternatives have become popular – in particular, saw palmetto.
The following briefly outlines the therapeutic effects of saw palmetto, particularly on prostate health and hair loss.
Remember to talk with your primary care doctor before starting any supplements, especially if taking other medications.
Prostate Health and Lower Urinary Tract Symptoms
Benign prostatic hyperplasia (BPH) primarily affects older men and is characterized by the nonmalignant enlargement of the prostate,  which contributes to frequent nighttime urination, inability to completely empty the bladder, and other urinary symptoms.  BPH progression is often associated with lower urinary tract symptoms (LUTS).  Studies have described that the actions of saw palmetto may help alleviate both symptoms of BPH and LUTS. [6, 7, 8]
One main cause of BPH: hormonal imbalance.
In BPH development, levels of 5α-dihydrotestosterone (DHT) are shown to be elevated. [3, 9] This is due to the lack of regulation in testosterone metabolism and conversion.
Mechanism of action #1: regulates DHT levels. Studies have shown that the compounds from saw palmetto effectively inhibited the enzyme (5α-reductase) that converts testosterone into DHT. [3, 9, 4, 10, 11] This enzyme has two types. Type II is found primarily in prostate tissue, where it is largely responsible for DHT production in these cells. 
Another potential cause: inflammation.
Studies have demonstrated a strong correlation between increased production of inflammatory compounds and BPH progression. 
Mechanism of action #2: anti-inflammatory effects. Results from a study showed decreased expression (production) of NF-kB, a compound that stimulates the synthesis of proteins involved with inflammation, in BPH rats that were treated with a particular extraction of saw palmetto – compared with the control group.  This data suggested possible anti-inflammatory effects of saw palmetto in BPH.
Another potential cause: apoptosis prevention.
It’s been observed that the prevention of apoptosis was also involved in the advancement of BPH. 
Mechanism of action #3: induces apoptosis. The same study above showed that saw palmetto promoted apoptosis by decreasing the production of the proteins that prevent this from happening. 
Preventing Hair Loss
One of the most common types of hair loss is caused by hormonal imbalance.  Similar to BPH, elevated levels of DHT has a negative effect; however, in AGA, this hormone causes miniaturization of the hair by inhibiting the cellular growth phase in hair development.  Saw palmetto is one of the medicinal plants that’s been studied to show the most evidence-based effect in preventing hair loss. 
As explained above, compounds from saw palmetto has the ability to inhibit 5α-reductase, thus lowering levels of DHT and allowing hair growth. [4, 10] One study investigated the effects of saw palmetto extracts on hair growth and regeneration. It was found that the extract performed higher efficacy for inhibiting 5α-reductase (in vitro assay) compared to the conventional drug Finasteride and promoted hair regeneration in mouse models. 
Lab and Clinical Studies
Although multiple studies (clinical and laboratory) have supported these potential mechanisms of action, there have been conflicting and inconsistent results.
The bioactive compounds in saw palmetto include phytosterols, fatty acids, and ethyl esters. [3, 13] One explanation for these contradictory results is the differing composition of extracts used – as there are various extraction techniques that can be used.  The composition and potency may differ between the extracted products, however one study found that all major types were able to inhibit the 5α-reductase enzyme. 
Several studies and reviews have reported the safety of saw palmetto use and has shown it to be well-tolerated with minimum side effects. [1, 2, 13, 10]
 National Center for Complementary and Integrative Health. (2016, September). Saw palmetto. https://www.nccih.nih.gov/health/saw-palmetto
 Healthwise Staff. (2018, June 18). Saw palmetto. https://www.uofmhealth.org/health-library/hw134773spec
 Sudeep, H. V., Venkatakrishna, K., Amrutharaj, B., Shyamprasad, A., & Shyamprasad, K. (2019). A phytosterol-enriched saw palmetto supercritical CO2 extract ameliorates testosterone-induced benign prostatic hyperplasia by regulating the inflammatory and apoptotic proteins in a rat model. BMC Complementary Medicine and Therapies, 19(270), 1-10. DOI: 10.1186/s12906-019-2697-z
 Skulj, A. Z., Poljsak, N., Glavac, N. K., & Kreft, S. (2019). Herbal preparations for the treatment of hair loss. Archives of Dermatological Research. DOI: 10.1007/s00403-019-02003-x
 Ooi, S. L., & Pak, S. C. Serenoa repens for lower urinary tract symptoms/benign prostatic hyperplasia: current evidence and its clinical implications in naturopathic medicine. The Journal of Alternative and Complementary Medicine, 23(8), 599-606. DOI: 10.1089/acm.2016.0302
 Kwon, Y. (2019). Use of saw palmetto (Serenoa repens) extract for benign prostatic hyperplasia. Food Science Biotechnology, 28(6), 1599-1606. DOI: 10.1007/s10068-019-00605-9
 Shao, Y. P., Xue, H. L., Shen, B. X., Ding, L. C., Chen. Z. S., & Wei, Z. Q. (2017). Saw palmetto fruit extract improves LUTS in type IIIA prostatitis patients. Zhonghua Nan Ke Xue, 23(5), 417-421. https://www.ncbi.nlm.nih.gov/pubmed/29717831
 Vela-Navarrete, R., Alcaraz, A., Rodriguez-Antolin, A., Minana Lopez, B., Fernandez-Gomez, J. M., Angulo, J. C., Castro Diaz, D., Romero-Otero, J., Brenes, F. J., Carballido, J., Molero Garcia, J. M., Fernandez-Proledesma, A., Cozar Olmos, J. M., Manasanch, D. J., Subriana Cachinero, I., Herdman, M., Ficarra, V. (2018). Efficacy and safety of a hexanic extract of Serenoa repens (Permixon®) for the treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH): systematic review and meta-analysis of randomized controlled trials and observational studies. BJU International, 122(6), 1049-1065. DOI: 10.1111/bju.14362
 Pais, P., Villar, A., & Rull, S. (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. Research and Reports in Urology, 8, 41-49. DOI: 10.2147/RRU.S96576
 Dhariwala, M. Y, & Ravikumar, P. (2019). An overview of herbal alternatives in androgenetic alopecia. Journal of Cosmetic Dermatology, 18(4). https://doi.org/10.1111/jocd.12930
 Rossi, A., Mari, E., Scarno, M., Garelli, V., Maxia, C., Scali, E., Iorio, A., & Carlesimo, M. (2012). Comparative effectiveness of finasteride vs. serenoa repens in male androgentic alopecia: a two-year study.
 Zhu, H. L., Gao, Y. H., Yang, J. Q., Li, J. B., & Gao, J. (2018). Serenoa repens extracts promote hair regeneration and repair or hair loss mouse models by activating TGF-β and mitochondrial signaling pathway. European Review for Medical and Pharmacological Sciences, 22(12), 4000-4008. DOI: 10.26355/eurrev_201806_15285
 Gordon, A. E., & Shaughnessy, A. F. (2003). Saw palmetto for prostate disorders. American Family Physician, 67(6), 1281-1283. https://www.aafp.org/afp/2003/0315/p1281.html