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Nettle Root, SHBG, and the Androgen Signal

Nettle root is the root of Urtica dioica, the stinging nettle. Folli-Activ lists nettle root extract among its ten oral ingredients. The papers that justify that line are androgen-binding experiments and a large benign prostatic hyperplasia trial. They are not scalp-hair trials, and they did not use a Folli-Activ capsule.

The root extract and the SHBG receptor

Sex hormone-binding globulin (SHBG) carries sex steroids in blood and also binds a receptor on cell membranes. Hryb, Khan, Romas, and Rosner tested extracts of Urtica dioica root against the binding of radiolabelled SHBG to its receptor on human prostatic membranes. An aqueous extract inhibited that binding. The effect was dose related, beginning around 0.6 milligrams per millilitre and complete at 10 milligrams per millilitre. An alcoholic extract, the nettle lectin Urtica dioica agglutinin, and stigmasta-4-en-3-one did not do this in the same assay. The active material, in this experiment, was in the aqueous root extract, and the readout was SHBG-receptor binding on prostate membranes.

Schöttner, Gansser, and Spiteller isolated lignans from polar extracts of the same roots: (+)-neoolivil, (−)-secoisolariciresinol, dehydrodiconiferyl alcohol, isolariciresinol, pinoresinol, and 3,4-divanillyltetrahydrofuran. They also tested the intestinal metabolites enterodiol, enterolactone, and enterofuran. In an in vitro binding assay, every lignan except (−)-pinoresinol bound human SHBG. The affinity of (−)-3,4-divanillyltetrahydrofuran stood out. This is a binding result. It places named nettle-root lignans on the carrier protein that holds androgens, which is a different measurement from a 5-alpha-reductase enzyme assay.

A rat model of testosterone-driven prostate growth

Nahata and Dixit induced prostatic hyperplasia in rats with testosterone at 3 milligrams per kilogram under the skin for 28 days. Alongside that stimulus they gave petroleum ether and ethanolic extracts of Urtica dioica at 10, 20, and 50 milligrams per kilogram by mouth, isolated beta-sitosterol at 10 and 20 milligrams per kilogram, or finasteride at 1 milligram per kilogram. They had also run in vitro work aimed at 5-alpha-reductase inhibitory activity and had isolated beta-sitosterol and scopoletin as marker compounds. Prostate-to-body-weight ratio, urine output, serum testosterone, prostate-specific antigen on day 28, and histology were the in-life readouts. Their conclusion from that package was that Urtica dioica fitted the management of benign prostatic hyperplasia in the model they built. Beta-sitosterol is a constituent they isolated from the plant. It is not a separate Folli-Activ ingredient, and this rat study is not a hair-count study.

The 620-patient urinary trial

Safarinejad ran a prospective, randomized, double-blind, placebo-controlled, partial crossover study of Urtica dioica for lower urinary tract symptoms secondary to benign prostatic hyperplasia. The blinded comparison lasted 6 months in 620 patients, and treatment then continued to 18 months after placebo recipients were switched to nettle. Of the enrolled men, 558 (90 percent) completed the study: 287 of 305 in the nettle group and 271 of 315 on placebo.

At 6 months, by intention to treat, 232 of 287 nettle patients (81 percent) reported improved urinary symptoms, against 43 of 271 placebo patients (16 percent), P less than 0.001. The International Prostate Symptom Score fell from 19.8 to 11.8 on nettle and from 19.2 to 17.7 on placebo, P = 0.002. Peak urinary flow rose by 8.2 millilitres per second on nettle and by 3.4 millilitres per second on placebo. Post-void residual urine in the nettle group fell from 73 to 36 millilitres. Prostate size on transrectal ultrasound fell from 40.1 to 36.3 cubic centimetres, P less than 0.001, and did not change on placebo. Serum PSA and testosterone did not change in either group. Men who kept taking the extract through 18 months kept the favorable values. The endpoint list is urinary symptoms, flow, residual urine, and a modest change in prostate volume. Hair was not an endpoint.

How this belongs in an oral hair formula

Patterned scalp thinning and benign prostate growth share an androgen vocabulary: testosterone, DHT, and the proteins that carry or make DHT. Peterson and Imperato-McGinley showed that men with lifelong 5-alpha-reductase deficiency have no temporal hairline recession and a small prostate together. Nettle root's published human trial is the prostate-symptom trial above, with testosterone left unchanged. Its published binding work is SHBG on prostatic membranes, not a scalp biopsy. Folli-Activ includes nettle root extract because that SHBG and prostate-symptom record is real, and because the formula's androgen layer is built to hold more than one published action. Saw palmetto's papers are about the enzyme that makes DHT. Nettle root's papers are about SHBG binding and urinary scores. Putting both in one bottle is a formulation choice based on those two literatures. It is not a combined hair trial, and this page does not convert an 81 percent urinary-symptom figure into an 81 percent hair figure.

The concentrations in the membrane assay, 0.6 to 10 milligrams per millilitre, are assay concentrations. They are not a labelled dose of the Folli-Activ capsule. The Safarinejad preparation was the extract used in that trial, at the schedule that trial used. Shoppers get a clean reading by keeping the endpoint attached to the number: flow, residual urine, symptom score, prostate volume.

Packs on this site

Folli-Activ is a 90-capsule oral bottle branded MY NPM FOLLI-ACTIV. On this site the packs are 1 bottle at RM169, 3 bottles at RM447, and 6 bottles at RM699 with free shipping. Checkout is by card. Nettle root extract is in the capsule. The binding curve and the urinary trial belong to the nettle preparations those investigators used.

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