Is saw palmetto as effective as finasteride against DHT?

Understanding the battle against DHT: a necessary introduction

Hair loss, especially in men, is strongly associated with a hormone called dihydrotestosterone, better known as DHT. This hormone is a more potent form of testosterone and is produced when an enzyme in the body called 5-alpha reductase converts testosterone into DHT.

When DHT levels are elevated in the scalp, hair follicles can shrink, weaken, and lead to progressive hair loss. This phenomenon is medically known as androgenetic alopecia.

Both finasteride and saw palmetto (Serenoa repens) have been studied as possible ways to slow or reverse this process, due to their ability to interfere with DHT production.

But are they equally effective?

Finasteride: a widely approved and studied inhibitor

Finasteride is a medication approved by the FDA (U.S. Food and Drug Administration) to treat both androgenetic alopecia and benign prostatic hyperplasia. Its mechanism of action is based on specifically blocking the type II 5-alpha reductase enzyme, which is mainly responsible for converting testosterone into DHT in the scalp and prostate.

In a study published in the Journal of the American Academy of Dermatology (Kaufman et al., 1998), the effects of 1 mg finasteride were analyzed in 1,553 men with androgenetic alopecia over a period of 2 years. It was a double-blind, randomized, placebo-controlled study. Evaluation was conducted through photographic hair counts and clinical assessments. Results showed that 83% of the men who took finasteride halted hair loss, and more than 60% showed visible hair regrowth.

Saw palmetto: the natural alternative seeking recognition

Saw palmetto is a plant extract derived from a small palm native to the southeastern United States. It has gained popularity as a natural treatment for hair loss based on its alleged ability to inhibit the 5-alpha reductase enzyme, similar to finasteride.

One of the most cited studies on saw palmetto was conducted and published in the Journal of Alternative and Complementary Medicine. In this study, 34 men with androgenetic alopecia were divided into two groups: one received a supplement of 200 mg of saw palmetto with 50 mg of beta-sitosterol twice daily, and the other received a placebo.

The study lasted 24 weeks. Evaluation was conducted through self-administered surveys and scalp photographs. Sixty percent of the group receiving the supplement showed improvement in hair loss, compared to 11% in the placebo group.

However, this study presents significant limitations that affect the reliability of its conclusions. Firstly, the sample size was very small (only 34 participants), which reduces the statistical power of the study to detect significant effects and to generalize the results to a broader population. Additionally, the trial duration was relatively short (24 weeks), making it difficult to assess long-term benefits or the sustainability of the effects.

Another critical issue is that the evaluations were based on self-assessments and scalp photographs—methods that are inherently subjective and susceptible to perception bias. The lack of quantitative tools such as hair counts, trichological analysis, or microscopic measurements diminishes the objectivity of the analysis, which seriously limits the accuracy and validity of the conclusions drawn.

Saw palmetto vs. finasteride: direct comparison in clinical evidence

In 2012, a comparative clinical study published in the International Journal of Immunopathology and Pharmacology directly evaluated the effectiveness of saw palmetto versus finasteride. The trial included 100 men with mild to moderate androgenetic alopecia over a 24-month period. One group took 320 mg of saw palmetto daily, and the other took 1 mg of finasteride. Results showed that 38% of those who took saw palmetto reported improvement, compared to 68% of the finasteride group. Evaluations were conducted through clinical examination and standardized photographs.

Although this study offers a head-to-head comparison, it also has weaknesses: it was not double-blind or placebo-controlled, which may introduce bias. Furthermore, although the duration was relatively long, the evaluation methods were clinical and did not include precise quantitative tools.

What does "inhibiting 5-alpha reductase" mean and why is it important?

To understand the differences between saw palmetto and finasteride, it's essential to grasp the role of the 5-alpha reductase enzyme. This enzyme exists in two main forms: type I and type II. Finasteride specifically inhibits type II, which is more prevalent in the scalp. Saw palmetto, on the other hand, appears to act on both, but in a weaker and less targeted way.

In vitro studies (in cells), such as the one by Sultan published in the Journal of Steroid Biochemistry, showed that saw palmetto extract can inhibit the activity of both isoforms of the enzyme. However, efficacy in cells does not always translate to the same effects in humans, due to the complexity of human metabolism and bioavailability (the amount of substance that actually reaches the target tissue).

User Experiences

Community feedback consistently indicates that saw palmetto is not as effective as finasteride when it comes to reducing DHT and preventing hair loss. However, some users have shared their positive experiences with saw palmetto, particularly when used alongside other treatments, though the consensus remains that its results are less reliable and less dramatic than finasteride.

One user shared their full regimen including saw palmetto tablets, 5% minoxidil spray, and weekly microneedling with a Derma Pen (1.5mm). They were afraid of taking finasteride due to potential side effects and opted for a natural alternative. Their photos showed regrowth, and they reported satisfaction with the results. In the discussion, others acknowledged the visible improvement but emphasized that the success was likely due to the combination of minoxidil and microneedling. Many advised that while saw palmetto may help marginally, it cannot replace finasteride in potency or reliability.

Another user documented their use of saw palmetto shampoo along with minoxidil, microneedling, and ketoconazole. While some thought there was mild improvement, many in the comments stated that these changes were likely subtle and temporary. The dominant suggestion was to add finasteride or dutasteride if serious results were desired, with others even recommending considering a transplant if the thinning worsened.

A long-term user of finasteride who had also previously used saw palmetto described the natural DHT blocker as “pretty much useless” in comparison. They argued that saw palmetto might inhibit 5-alpha-reductase to a minor degree, but does not suppress scalp DHT levels effectively. They reported dramatic improvements only after switching to finasteride and were vocal about how finasteride "saved" their hair.

Some users do stack saw palmetto with finasteride or minoxidil, such as one detailed post where a user combined finasteride 0.5mg daily with saw palmetto 400mg/day and multiple topicals like peppermint and jojoba oil. Their 3-month results were described as “stunning,” but it was widely agreed that finasteride and microneedling were likely doing the heavy lifting, with saw palmetto viewed as a minor supplement.

Lastly, a 13-month progress update from a user on oral finasteride and topical minoxidil included mention of saw palmetto as part of their supplement stack. However, they made it clear that their core treatment centered around finasteride and minoxidil, which had produced visible regrowth. They were still considering a transplant for density, indicating that even with this aggressive stack, full recovery was not achieved.

Can saw palmetto replace finasteride?

Current science suggests that saw palmetto may be a useful option for those seeking natural alternatives to finasteride treatment, especially if they are concerned about side effects.

However, the evidence also shows that its effectiveness is more limited. Finasteride remains by far the treatment with the most scientific support for reducing DHT levels and slowing hair loss in men.

This does not mean saw palmetto has no value—it simply indicates that more robust research is still needed, with large samples, objective evaluations, and rigorous methodologies to clearly determine its place in the treatment of androgenetic alopecia.

References in APA 7 format:

Kaufman, K. D., Olsen, E. A., Whiting, D., Savin, R., DeVillez, R., Bergfeld, W., ... & Finasteride Male Pattern Hair Loss Study Group. (1998). Finasteride in the treatment of men with androgenetic alopecia. Journal of the American Academy of Dermatology, 39(4), 578–589. https://pubmed.ncbi.nlm.nih.gov/9768724/

Prager, N., Bickett, K., French, N., & Marcovici, G. (2002). 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. Journal of Alternative and Complementary Medicine, 8(2), 143–152. https://pubmed.ncbi.nlm.nih.gov/12006122/

Rossi, A., Mari, E., Scarno, M., Garelli, V., Maxia, C., Scali, E., & Carlesimo, M. (2012). Comparative effectiveness of finasteride vs. Serenoa repens in male androgenetic alopecia: a two-year study. International Journal of Immunopathology and Pharmacology, 25(4), 1167–1173. https://pubmed.ncbi.nlm.nih.gov/23397605/

Sultan, C., Terraza, A., Devillier, C., Mahoudeau, J., & Belon, P. (1984). Inhibition of androgen metabolism and binding by a liposterolic extract of Serenoa repens B in human foreskin fibroblasts. Journal of Steroid Biochemistry, 20(1), 515–519. https://pubmed.ncbi.nlm.nih.gov/6238491/