Saw palmetto is one of the most widely used “natural” products for hair loss. Many people use it as a botanical alternative to finasteride for treating male pattern hair loss. The key issue here is not whether it is popular but rather if it actually works, and how well it stacks up against prescription treatments.
Saw Palmetto Mechanism of Action
Male pattern hair loss (androgenetic alopecia) is caused by dihydrotestosterone (DHT), a hormone formed by the conversion of testosterone via the enzyme 5-alpha reductase. As DHT builds up over time in genetically susceptible individuals, it will eventually cause the miniaturization of their hair follicles, resulting in progressively thinner and shorter hairs. Finasteride, approved by the FDA for male pattern hair loss, decreases serum DHT levels by approximately 60 to 70 percent at its recommended daily dose of 1 milligram per day.
Saw palmetto blocks the action of 5-alpha reductase but to a much lesser extent. In a study conducted by Marks et al. (2000), men taking 320 milligrams per day of saw palmetto extract demonstrated an approximate 32 percent decrease in serum DHT. Other studies show DHT reductions ranging from 25 to 35 percent, depending on the formulation. In summary, saw palmetto will decrease DHT levels, but it will do so significantly less effectively than finasteride.
Will Saw Palmetto Really Make Your Hairs Grow Back?
The evidence base for saw palmetto’s efficacy is relatively weak and largely limited to a few small-scale studies.
A comparative study involving 150 men with mild to moderate male pattern hair loss was carried out by Rossi et al. (2012) for two years using either 1 mg finasteride or 320 mg saw palmetto. Approximately:
• 68 percent of the men treated with finasteride demonstrated improvements in their hair loss.
• 38 percent of the men treated with saw palmetto showed some degree of improvement.
Although saw palmetto did appear to offer some level of benefit in the case of early hair loss, it was undoubtedly far less successful than finasteride, particularly in more advanced stages of hair loss.
In addition to the above-mentioned comparative study, there is another smaller randomized clinical trial (Prager et al., 2002) that suggested saw palmetto offered only minimal benefits relative to the placebo group. However, both the sample size and design of this study severely limit the ability to draw firm conclusions. Finasteride, on the other hand, has been tested in several large-scale, placebo-controlled studies demonstrating significant statistical increases in the number of hairs per unit area of scalp and slowing of the rate of hair thinning. Overall, while saw palmetto may provide some form of benefit to some patients experiencing early-stage hair loss, it is clearly less potent than pharmaceuticals.
Side Effects of Saw Palmetto on Sexuality
Given that saw palmetto reduces DHT levels, it would be rational to assume that it could potentially result in sexual side effects identical to those experienced with finasteride.
Reported side effects in clinical studies and post-marketing surveillance studies for saw palmetto include:
• Diminished libido
• Erectile dysfunction
• Decreased ejaculate volume
• Less frequent reports of breast tenderness or enlargement
However, the incidence of sexual side effects observed in the large clinical trials assessing saw palmetto for reducing prostate symptomatology, such as the CAMUS trial (Avins et al., 2013), were generally comparable to those found in the placebo groups. That being said, although there are many anecdotal accounts and reports contained within pharmacovigilance databases, the available information suggests that sexual side effects may occur when using saw palmetto. Although they seem to be less common than with finasteride, they are still possible. Important Point: “Natural” does not mean “biologically inert.” Any compound that has a biological effect, particularly one that significantly impacts DHT, is capable of impacting androgen-sensitive tissues.
Positioning Saw Palmetto in Treatment Paradigm
Saw palmetto may be a viable option for individuals who:
• Want to pursue a non-pharmacologic (non-prescription) treatment strategy
• Are unwilling to use finasteride
• Do not qualify for pharmacologic (prescription) 5-alpha reductase inhibitors
This product should be marketed as a lower-potency DHT modulator with realistic expectations. It is highly unlikely that saw palmetto will reverse the miniaturization of follicles that has already occurred due to androgenetic alopecia, and therefore it is best to consider it as a mild adjunctive therapy.
Stronger medical therapy is generally required in men with progressive androgenetic alopecia to arrest their condition.
Conclusion
While saw palmetto can decrease DHT by approximately 25 to 35 percent, as opposed to 60 to 70 percent with finasteride, the majority of clinical research indicates that it provides only slight advantages in improving hair growth among men with early stages of androgenetic alopecia, and these results are significantly weaker than those obtained with prescribed medications.
There have also been reports of sexual side effects associated with saw palmetto use. However, rates of these side effects in clinical trials are generally equivalent to those of the placebo arms. While the likelihood of developing sexual side effects seems to be lower with saw palmetto than with finasteride, it is not nonexistent.
When determining the course of treatment for hair loss, including whether to utilize pharmacologic agents or dietary supplements, it is imperative to establish an accurate diagnosis of the underlying cause of hair loss. Not all types of hair loss are driven by DHT, and treatment recommendations should be tailored to each patient’s specific needs, based on the severity of their hair loss, their risk tolerance, and their ultimate therapeutic goals. Regardless of whether the selected therapy is a prescription medication or a dietary supplement, evidence-based decision-making is essential to making informed choices.
Schedule a Consultation
If you are interested in learning more about finasteride, saw palmetto, and their role in hair loss and hair restoration, contact the Gabel Center for Hair Restoration at our Portland Hair Restoration office. Our team specializes in the diagnosis and treatment of hair loss disorders, as well as advanced surgical hair restoration including Follicular Unit Extraction procedures. Schedule a consultation to receive a personalized evaluation and discuss the most appropriate treatment options for your specific condition.
References
Avins AL, Bent S, Staccone S, et al. A randomized trial of saw palmetto for lower urinary tract symptoms. JAMA. 2013;309(13):1340–1347.
Marks LS, Partin AW, Epstein JI, et al. Effects of a saw palmetto herbal blend in men with symptomatic benign prostatic hyperplasia. J Urol. 2000;163(5):1451–1456.
Prager N, Bickett K, French N, Marcovici G. A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia. J Altern Complement Med. 2002;8(2):143–152.
Rossi A, Mari E, Scarno M, et al. Comparative effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study. Int J Immunopathol Pharmacol. 2012;25(4):1167–1173.
