The saw palmetto plant, or Serenoa repens, is a small palm tree native to the southeastern United States, particularly abundant in states like Florida and Georgia. For centuries, the deep purple berries of this plant have been a component of traditional medicine, used by Native Americans to address urinary and genital issues.
Prostate and Urinary Health
The most common application for saw palmetto is in managing lower urinary tract symptoms associated with an enlarged prostate. This condition, benign prostatic hyperplasia (BPH), is a non-cancerous increase in prostate size that can interfere with urination. Symptoms that may be addressed include a frequent or urgent need to urinate, increased urination at night (nocturia), and a weak or interrupted urine stream. BPH is a common part of aging for men, affecting a large percentage of those over 50.
The proposed mechanism involves inhibiting the enzyme 5-alpha-reductase. This enzyme is responsible for converting testosterone into a more potent androgen called dihydrotestosterone (DHT). DHT is a contributor to prostate growth, so by reducing its production, saw palmetto is thought to help control the enlargement of the gland. The active ingredients believed to be responsible are the fatty acids and phytosterols contained within the berries.
Scientific evidence regarding saw palmetto’s effectiveness for BPH is inconsistent. Some studies show it to be as effective as certain prescription medications, with one analysis finding it decreased nighttime urination and improved urine flow. Other research, however, has failed to show a significant difference between saw palmetto and a placebo. This discrepancy may be due to variations in the preparations used, as the concentration of active compounds can differ between products.
Hormonal and Hair Growth Applications
The hormonal actions of saw palmetto extend beyond prostate health, leading to its use in managing hair loss. The same mechanism that may benefit the prostate—reducing DHT—is also implicated in androgenetic alopecia, or pattern baldness. Elevated DHT levels in hair follicles are known to shorten the hair growth cycle and lead to thinner, shorter hairs, eventually causing them to stop growing altogether.
By potentially lowering DHT levels in the scalp, saw palmetto may help slow this process and support hair growth in both men and women experiencing this type of hair loss. This application is considered less established than its use for BPH, but its popularity is growing as more people seek alternative approaches to hair thinning. The supplement is thought to work by preventing DHT from binding to its receptors in the follicles.
This role in modulating androgen activity has also led to its exploration for other hormone-related conditions. While its primary focus is on blocking the conversion of testosterone to DHT, this interaction is part of the body’s complex endocrine system. It is important to note that claims about its ability to regulate overall testosterone levels are not well-supported by extensive research.
Other Potential Health Applications
Saw palmetto is associated with other potential benefits, though the scientific backing is more limited. Some people use the supplement to support libido and sexual function, with one pilot study noting improvements in this area alongside BPH symptom relief. The berries have also been traditionally used for their purported ability to reduce inflammation.
Additionally, there is some speculative interest in its use for conditions like Polycystic Ovary Syndrome (PCOS), which involves hormonal imbalances. However, the evidence for these applications is largely anecdotal or derived from preliminary laboratory studies rather than robust human clinical trials.
The claims that saw palmetto can increase sperm production or breast size are not supported by clinical research.
Forms, Dosage, and Safety Considerations
Saw palmetto is available in several forms. The most studied are standardized extracts, processed to contain a specific concentration of fatty acids, usually 80% to 90%. These extracts are what have been used in most clinical trials. Common forms include:
- Dried berries
- Teas
- Liquid preparations
- Capsules
A dosage used in research for BPH symptoms is 320 milligrams per day, sometimes taken as a single dose or split into two 160-milligram doses. Follow the dosage instructions on the product label, as the concentration of active compounds can vary. Consulting with a healthcare provider before starting any new supplement is recommended to ensure it is appropriate for your specific health needs.
Saw palmetto is considered safe for most adults but can cause mild side effects like digestive upset and headaches. Due to its effects on hormones, it is not recommended for pregnant or nursing women. Individuals taking other hormone-related medications, such as hormone replacement therapy or certain contraceptives, should also consult a doctor before using saw palmetto to avoid potential interactions.