T Nation

increasing free testosterone

I wonder why no one has done anything with these results??? Seems like urtica dioica extract (with a high concentration of 3,4-divanillyltetrahydrofuran) would make a good additive to a product like M or Tribex.


Lignans from the roots of Urtica dioica and their metabolites bind to human sex hormone binding globulin (SHBG).

Schottner M, Gansser D, Spiteller G.

Lehrstuhl Organische Chemie I, Universitat Bayreuth, Germany.

Polar extracts of the stinging nettle (Urtica dioica L.) roots contain the ligans (+)-neoolivil, (-)-secoisolariciresinol, dehydrodiconiferyl alcohol, isolariciresinol, pinoresinol, and 3,4-divanillyltetrahydrofuran. These compounds were either isolated from Urtica roots, or obtained semisynthetically. Their affinity to human sex hormone binding globulin (SHBG) was tested in an in vitro assay. In addition, the main intestinal transformation products of plant lignans in humans, enterodiol and enterolactone, together with enterofuran were checked for their activity. All lignans except (-)-pinoresinol developed a binding affinity to SHBG in the in vitro assay. The affinity of (-)-3,4-divanillyltetrahydrofuran was outstandingly high. These findings are discussed with respect to potential beneficial effects of plant lignans on benign prostatic hyperplasia (BPH).

The effect of extracts of the roots of the stinging nettle (Urtica dioica) on the interaction of SHBG with its receptor on human prostatic membranes.

Hryb DJ, Khan MS, Romas NA, Rosner W.

Department of Medicine, St. Luke’s/Roosevelt Hospital Center, New York, N.Y. 10019.

Extracts from the roots of the stinging nettle (Urtica dioica) are used in the treatment of benign prostatic hyperplasia. The mechanisms underlying this treatment have not been elucidated. We set out to determine whether specific extracts from U. dioica had the ability to modulate the binding of sex hormone-binding globulin to its receptor on human prostatic membranes. Four substances contained in U. dioica were examined: an aqueous extract; an alcoholic extract; U. dioica agglutinin, and stigmasta-4-en-3-one. Of these, only the aqueous extract was active. It inhibited the binding of 125I-SHBG to its receptor. The inhibition was dose related, starting at about 0.6 mg/ml and completely inhibited binding at 10 mg/ml.

Mike, I’m pretty much in the same boat as you,
“T” wise. Having read some articles by Dan Duchaine
a few years back about stinging nettles and their effect on free testosterone prompted me to do some research of my own. I began taking stinging nettles 3 years ago… not sure how much at first, but over the last year have been using 2 grams daily in an 1:1 alcohol extract. Results: nothing to write home about…NOTHING… It has not panned out to be the miracle elxir I had hoped for! Mike, keep up the research and give it a try yourself; maybe stinging nettles just might work for you…?

It’s lengthy to explain, but I’ve written
before about why the widely held belief
that “freeing up testosterone from being
tied up by SHBG and thereby increasing
levels” (to paraphrase the concept) is entirely incorrect. Most likely a search
on SHBG, or perhaps also including my name,
would turn them up.

Bill’s explanation certainly makes sense. If correct, it would mean that completely inhibiting SHBG would have no effect on free testosterone levels. I might try supplementing with stinging nettle and have my T levels tested to verify the hypothesis.