The Truth About Saw Palmetto for Hair Loss

Saw Palmetto, also known as Serenoa Repens, has been touted on the internet for several years to be an effective remedy against hair loss. It supposedly does so by reducing the amount of DHT (dihydrotestosterone). A quality shared with the anti-hair loss medicine finasteride.

The study referred to dates back to 1984. A laboratory study that used extremely high doses of saw palmetto, rendering the results practically irrelevant.

Nevertheless, the study has been cited in several research papers as proof of Saw Palmetto's efficacy. And that is good news for the companies that are selling it. Suddenly, Saw Palmetto supplements are being rebranded as "Hair Loss Capsules" including catchy slogan "For Longer, Healthier and Thicker Hair".

A health claim that is not allowed to be made due to a lack of evidence. Such violations are hardly ever acted upon. Which is understandable. The cosmetics industry is enormous. Reviewing the validity of every single claim is impossible. We therefore decided to take it upon ourselves to see if the claims hold up when put to the test.

Motivation article

The health claims that are thrown around here and there make it difficult for the reader to distinguish between sense and nonsense. And to be honest, they also get on our nerves. In this article we aim to provide an unbiased analysis of the efficacy of saw palmetto as a treatment for hair loss.

Saw Palmetto and DHT.

Want to know if a product stops hair loss? Then you need to measure its efficacy on DHT. DHT stands for dihydrotestosterone, a male androgen primarily responsible for hereditary hair loss.² It is a hormone resulting from the interaction between testosterone and the enzyme 5 alpha-reductase.

Hair follicles that come into contact with DHT become damaged and, over time, lose their ability to produce thick and long hair. This process takes several years, but ultimately leads to what we call androgenetic alopecia, or male pattern hair loss.

Finasteride, a medicine for hair loss, stops this process by reducing the amount of DHT by about 70%.³ It does so by inhibiting the 5 alpha-reductase enzyme, causing less testosterone to be converted into DHT.

Saw Palmetto is claimed to be able to lower DHT just like finasteride does by inhibiting this same enzyme. On the internet it’s often recommended as the natural alternative to finasteride. Until recently, it was even listed on Wikipedia as a valid substance that inhibits 5α-reductase.

A statement that’s incorrect and therefore removed by us from the list. A commercial party (Permixon)has made several attempts to register Saw Palmetto as an valid 5α-reductase inhibitor with the European Union. Due to a lack of evidence, their attemps to do so have so far been rejected.⁴

Despite all this, Saw Palmetto remains immensely popular. In this article we examine whether this popularity is justified. We analyse the studies and determine if the claims that are made hold up when put under scrunity.

saw palmetto as a 5 alpha-reductase inhibitor

The idea that saw palmetto inhibits the enzyme 5 alpha-reductase has been confirmed by several studies.⁵ ⁶ ⁷ The enzyme consists of types I, II and III. Finasteride inhibits 5α-reductase isoenzymes II and III while Saw Palmetto inhibits I and II. In order to stop hair loss, the ability to inhibit enzyme type II is the most important.

Saw Palmetto's ability to inhibit this enzyme type requires, however, a bit more context. Namely that this inhibition is extremely low and has no clinical relevance whatsoever for stopping hair loss. Finasteride for example, is 18.000 times more powerful in inhibiting enzyme type II compared to Saw Palmetto.

Efficacy of saw palmetto vs finasteride in vitro

One study that is often cited is a research paper published in 2005.⁸ Where they compared the 5-reductase activity of finasteride with Permixon® in prostate cancer cells.

The authors of this study conclude:

Serenoa repens (10 ug/ml) clearly inhibited the activities of both isoenzymes to a similar extent (5aR-I, 72% decrease; 5aR-II, 76% decrease). Although finasteride (5 nM) had a similar inhibitory effect on 5R-II (83% decrease) compared to Serenoa repens, at the concentration used it had no effect on the 5R-I activity of the cells.

At first glance, it seems that both means are equally effective. After all, a decrease of 76% and 83% is almost identical. However, this changes once you realise that 5 nM finasteride is equivalent to 0.00186 ug/ml finasteride. The study therefore compared 10 ug/ml Saw Palmetto with 0.00186 ug/ml finasteride. A ratio of 5376:1. In other words, in this study: 1 mg finasteride was equally effective as 5376 mg saw palmetto

But, and this is important: this study was done in vitro ! Meaning, a study carried out in a laboratory. A dose effective in the lab rarely corresponds to one that is effective in a living organism. A dose that is effective in humans.

Efficacy of saw palmetto vs finasteride in vivo

A study that illustrates this well is a study published in 1994.⁹ A study that examined and compared the efficacy of Saw Palmetto and finasteride in the laboratory (in vitro), as well as in a living organism (in vivo). Their labresults proofed 1 mg finasteride to be as effective as 5600 mg of saw palmetto. A ratio of 1:5600 and almost identical to the ratio from the previous study (1:5376).⁸

In the second part of the study, they put these dosis to the test in a living organism; the rat. In the second part of the study, a dose of 0.1 mg finasteride proved effective. Provided that the ratio of 1:5600 from the labresults also apply to a living organism, you arrive at a theoretical dose of 560 mg saw palmetto (0.1 x 5600).

However, although a dose of 0.1 mg of finasteride proofed sufficient, 560 mg of saw palmetto did not. In fact, even a dose of 1800 mg of saw palmetto proved to have no effect at all. A ratio of at least 1:18.000 when compared to finasteride.

A ratio that is substantially higher than the labresults indicated it would be. The reason “why” is because finasteride and saw palmetto differ in how they are absorbed, metabolised and distributed in the tissue.

Why Saw Palmetto isn’t effective

In the lab, saw palmetto is injected at the place where they want it to be active: the cell. Things like bioavailability and absorption rate don’t matter then. This is different when the drug is ingested by a rat or a human, as the above study has shown.

In the case of finasteride - it’s absorbed both better and faster. Saw Palmetto, on the other hand, has little practical value in reducing DHT. Namely, because a dose of 18.000 mg corresponds to 50 capsules of 360 mg.

And you have to remember that even a ratio of 1:18.000 was shown to be not enough. So we are talking about the bare minimum here. The only study to examine the effect of saw palmetto on DHT in humans found no effect.¹⁰ In the study, a 5 mg dose of finasteride reduced serum DHT by 65% after only 12 hours, while a 320 mg dose of Permixon proofed ineffective.

Final word

Saw palmetto has not been effective in treating hair loss. Laboratory studies do show an effect, but the extremely high doses used make it irrelevant from a practical point of view.

The fact that Saw Palmetto is still seen as an effective DHT blocker today seems to be mainly due to the PR team behind the Permixon brand. A brand owned by Pierre Fabre Laboratories; a pharmaceutical company that published two studies in 1984 and 1996, both conducted by their own researchers and in their own research facility, the Centre de Recherches Pierre Fabre.111

A laboratory study in which cell cultures were exposed to extremely high doses of saw palmetto, that potentially destroyed their cellular function. Rendering the study results pretty much useless. We therefore determine that the anti-hair loss claims attributed to Saw Palmetto are invalid and unjustified. They appear to be primarily a tactical means of stimulating sales and thus increasing turnover.

For treating male hair loss its efficacy remains unproven. Use of Saw Palmetto is not recommended. Doing so would be a waste of time.