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Saw Palmetto and the Enzyme That Makes DHT

Saw palmetto is the berry of Serenoa repens, and the ingredient used in research is a liposterolic extract of that berry. Folli-Activ includes saw palmetto in its oral 10-in-1 formula. The papers below tested their own extracts, including the branded extract Permixon and a liposterolic extract abbreviated LSESr. They did not test a Folli-Activ capsule.

Both enzyme types, with measured inhibition constants

Human steroid 5-alpha-reductase converts testosterone to dihydrotestosterone (DHT). There are two isoforms. Iehlé and colleagues expressed each isoform separately in insect cells and measured how a lipido-sterol extract of Serenoa repens inhibited them. The type 1 enzyme had a neutral pH optimum and a Km for testosterone of 2.9 micromolar. The type 2 enzyme had an acidic pH optimum and a Km of 0.5 micromolar. LSESr inhibited both. The inhibition constants were 7.2 micrograms per millilitre for type 1 and 4.9 micrograms per millilitre for type 2. The kinetics were not the same as the azasteroid drugs in that paper: LSESr was non-competitive against the type 1 enzyme and uncompetitive against the type 2 enzyme. Finasteride and turosteride, by contrast, were selective for type 2.

That is an enzyme result. It tells a formulator why a saw palmetto extract is discussed next to DHT. It does not, by itself, tell a shopper how many micrograms per millilitre a daily capsule will produce in blood.

Prostate cells: enzyme down, PSA secretion maintained

Bayne, Donnelly, Ross, and Habib tested Permixon in a coculture model of benign prostatic hyperplasia at 10 micrograms per millilitre, the concentration they calculated as the therapeutic plasma level for the recommended dose of that product. At that concentration Permixon inhibited both 5-alpha-reductase type I and type II. Prostate-specific antigen secretion from the epithelial cells continued, including after testosterone stimulation. Electron microscopy showed lipid accumulation in the cytoplasm and damage to intracellular membranes in treated cells.

Habib, Ross, Ho, Lyons, and Chapman extended the same observation to human prostate cancer cell lines. Serenoa repens inhibited 5-alpha-reductase activity and did not suppress PSA protein expression. Reporter-gene experiments showed that Permixon did not block androgen-receptor activation of the PSA promoter, and both testosterone and DHT kept that transcriptional activity going. In these prostate-cell systems the extract inhibited the enzyme that makes DHT and left PSA secretion intact.

Peterson, Imperato-McGinley, and colleagues had already shown, in men born with 5-alpha-reductase deficiency, what a lifetime of very low DHT does to hair pattern: no temporal hairline recession, less body hair, and a small prostate, with high testosterone-to-DHT ratios. The enzyme papers and the genetic paper describe the same enzyme from opposite directions. One is a botanical extract in a test tube and in cultured prostate cells. The other is an inherited enzyme deficiency in people.

The two-year hair photograph study

Rossi and colleagues ran an open-label study, not a placebo-controlled trial, in 100 men with mild to moderate androgenetic alopecia. One group took Serenoa repens 320 milligrams every day for 24 months. The other took finasteride 1 milligram every day for the same period. A score based on global photographs at the start and at 24 months was the efficacy measure. An increase in hair growth was recorded in 38 percent of the Serenoa repens group and in 68 percent of the finasteride group. In men with level II and III alopecia, finasteride was the stronger result for 33 of 50 patients, which is 66 percent. The clinicians also recorded a regional difference: finasteride changed both the front and the vertex, and Serenoa repens changed the vertex.

Those percentages belong to that open-label comparison of 320 milligrams of Serenoa repens against 1 milligram of finasteride. They are not a Folli-Activ result, and they are not a claim that saw palmetto outran finasteride. On the scoring method used, 38 percent of men in the Serenoa arm showed increased hair growth at two years, and that change clustered at the vertex.

A pilot that mixed saw palmetto with beta-sitosterol

Prager, Bickett, French, and Marcovici ran a randomized, double-blind, placebo-controlled pilot of botanically derived 5-alpha-reductase inhibitors in men aged 23 to 64 with mild to moderate androgenetic alopecia. The active formulation was liposterolic extract of Serenoa repens plus beta-sitosterol. Blinded staff rated 60 percent of the active group improved at the final visit, which was 6 of 10 men. Beta-sitosterol is not one of the ten Folli-Activ ingredients. The pilot supports a statement about that combination, and only about that combination. It is the wrong paper to quote as a pure saw palmetto result.

On this site

Saw palmetto is one ingredient in a 90-capsule bottle of Folli-Activ, sold as MY NPM FOLLI-ACTIV. Packs are on this site: 1 bottle at RM169, 3 bottles at RM447, and 6 bottles at RM699 with free shipping. Checkout is by card. The enzyme work, the prostate-cell work, and the two-year photograph study are the reasons the ingredient is in an oral hair formula. The capsule those investigators used was theirs. The capsule here is a 10-in-1 formula that includes saw palmetto alongside nine other ingredients with their own papers.

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