*** Urtica Dioica - a useful testosterone booster supplement? ***

By James Collier BSc (Hons) RNutr, Nutrition Consultant and MuscleTalk Co-Owner

You may have seen the compound urtica dioica labelled on supplement packages as 'nettle root' because it is a herb derived from the natural lignan divanil found in stinging nettle roots. It is included as a principle ingredient in a number of 'testosterone boosting' formulas due to its claimed effect on making testosterone more available to tissues for muscle growth, i.e. rather than increasing the amount of free testosterone in circulation, it helps it bind to muscle cells in order to exert its effects.

The way your body controls testosterone is quite complex, but involves a protein called Sex Hormone Binding Globulin (SHBG), and some testosterone present in the blood is 'free' and some is 'bound'. SHBG regulates the amount of testosterone which attaches to the androgen receptor of the cell, and it is through testosterone-to-androgen receptor interaction that protein synthesis is promoted; and protein synthesis equals muscle growth. Urtica dioica inhibits the SHBG molecule, activating a much larger percentage of your testosterone. Therefore the theory is more is available to muscle cells and there is a greater level of protein synthesis.

Although the theory is sound, there is no substantiated evidence that urtica dioica does actually give the desired outcome of increased gains. Firstly, the significance of the effect of urtica dioica on SHBG is not known; i.e. how efficient at inhibiting SHBG is it, and how much free testosterone is actually taken up by muscle cells because of it? And secondly, there is no evidence showing that supplementing with urtica dioica does actually improve performance or muscle growth.

Urtica dioica has also claimed to also have other beneficial effects either related to its action on SHBG or though its antioxidant activity. It supposedly improves blood sugar and insulin control, boosts nitric oxide (NO) helping to give better muscle pumps, promotes prostate health, lowers blood pressure, promotes healthy cholesterol levels and has anti-oxidant, anti-microbial, anti-ulcer and anti-inflammatory behaviour. Some of these claims are backed up by well designed studies, particularly the area of prostate health which looks encouraging. However, the significance that urtica dioica really has on any aspects of performance and health, has not really been shown, and its popularity really stems from clever marketing.

There is no direct evidence linking intake of urtica dioica to increased gains or improved performance in any respect, and there needs to be a lot more research into this herb before products containing it carry any notable credibility. So although I wouldn't shun urtica dioica altogether, I'm far from getting exited about it, particularly as the products tend to be extremely expensive.

Source: The MuscleTalker - Issue 61 (May 2007) - MuscleTalk.co.uk Newsletter