Saw palmetto extracts have been used to treat urinary symptoms resulting from benign prostatic hyperplasia, in addition to treating pelvic pain, migraines, and hair loss. Here we discuss the evidence behind its current medical uses.
Saw palmetto (Serenoa repens) is a small palm tree originally found in Southeastern United States. The active parts of this plant are the sterols and free fatty acids found in its berry. The extracts of its fruit are used in tablets or capsules, and can also be ground, dried, sold as whole berries, liquid extract, or tea. The most commonly studied form of saw palmetto is Permixon, which includes the solvent hexane, while other formulations use ethanol, methanol, and liquid carbon dioxide as solvents.
Saw palmetto has been used for urinary symptoms resulting from benign prostatic hyperplasia, in addition to treating pelvic pain, decreased sex drive, migraines, as well as hair loss.
There are multiple proposed mechanisms of the health benefits of saw palmetto, including its anti-inflammatory activity and how it blocks the conversion of testosterone to dihydrotestosterone, which is a hormone that stimulates the development of male characteristics. In addition, saw palmetto has similar effects to using the prostate prescription medicine finasteride (Proscar) for prostate shrinkage.
Saw palmetto for prostate disorders
In 2011, multiple studies involving saw palmetto evaluated by the National Institute of Health found that saw palmetto does not work better than a placebo, even when used in amounts up to three times the recommended dose. For instance, saw palmetto was not proven to affect readings of prostate-specific antigen (PSA) levels, even when consumed in large amounts. PSA is a protein made in the prostate gland and PSA levels are used to screen for prostate cancer in addition to monitor patients with prostate cancer. Another study including more than 1,000 patients did not find that saw palmetto decreased PSA levels, but finasteride decreased PSA levels by 41%.
Treatments for benign prostatic hyperplasia (BPH) are evaluated based on their effects on symptoms including diminished urine stream, post-void dribbling, overflow incontinence, and urinary retention in addition to measuring urine flow rate, changes in prostate size, and residual volume.
In 2002, a large analysis evaluated the results from 21 studies comparing saw palmetto with placebo and other drugs ranging from four to 48 weeks and included 3,139 men with an average age of 65 years. All of the men had moderate symptoms, and in the 13 studies that reported symptom scores, saw palmetto was determined to improve symptom scores, individual symptoms, and flow measures more than placebo.
In addition, the 12 studies that reported urination at night found that saw palmetto reduced symptoms by 25% compared with placebo. Lastly, two studies found that saw palmetto and finasteride had similar effects on decreasing urinary symptom scores and improving peak urine flow.
Saw palmetto for hair loss
Several studies have attempted to determine the effectiveness of saw palmetto for reducing hair loss. One included 10 participants between 23 and 64 years old who consumed saw palmetto for five months and found a 60% improvement in hair growth. Another study included 50 participants who consumed saw palmetto every day for 24 months and found that 38% of the participants had an increase in hair growth, especially on the top of the head.
Furthermore, a study divided 62 participants into three groups: the first received shampoo and lotion enriched with saw palmetto in addition to a daily saw palmetto supplement, the second group received placebo equivalents, and the third group used the saw palmetto shampoo and lotion with a placebo supplement.
The group using both placebo products had no additional hair growth, while both of the other groups had an increase in hair growth between 20% and 35%. Lastly, the group taking the saw palmetto supplement in addition to the saw palmetto enriched shampoo experienced the most hair growth.
Safety of saw palmetto
The majority of safety information regarding saw palmetto comes primarily from studies in men. There is little known about the safety or side effects of saw palmetto in women or children. Nonetheless, saw palmetto has been reported to be well tolerated and may cause mild side effects such as digestive symptoms or headaches. Saw palmetto can interact with some medications, such as hormone replacement therapies and blood thinners.
Written by Tatsiana Verstak, M.S., B.S.
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- Saw palmetto by the NIH: National Center for Complementary and Integrative Health. Last modified December 01, 2016.
- Saw Palmetto for Prostate Disorders. Gordon, A. and Shaughnessy, A. Am Fam Physician. 2003 Mar 15; 67(06):1281-1283.