Summary: Definitely not essential for boosting testosterone levels although can certainly be helpful combined with other ingredients. I would not bother taking this as a stand alone supplement if my only goal was to increase my testosterone levels.
You can see which supplements I do recommend taking over here.
Stinging nettle ( botanical name : Urtica dioica) is a medicinal plant with an array of beneficial effects in many human diseases. The plant is commonly called as stinging nettle because the stem and leaves possess hairy structures called trichomes that cause a stinging sensation on touching. Traditional herbal medicine describes the use of almost all parts of this plant in many diseases like kidney disorders, arthritis and gastrointestinal tract ailments. However the most elaborately studied and reported use is of root extracts for treating benign prostate hyperplasia (prostate enlargement). Studies on rats and human clinical studies show very promising effect of nettle extract in managing prostate enlargement, relieving the symptoms in lower urinary track and increasing the testosterone levels. Important clinical and animal studies on effect of nettle extract are summarized here.
Nettle extract helps in relieving prostate enlargement
Study: A clinical study was conducted on 100 Benign Prostatic Hyperplasia (prostate enlargement) patients aged between 40-80 years. Main exclusion criterion for the study was acute renal problems like severe infections and failure. Patients were given 300mg nettle extract two times a day for 8 weeks. The effect of extract was evaluated by observing reduction of clinical symptoms in the patients after two months.
Result: As compared to the placebo group authors found that symptoms of enlarged prostate were relieved in the patients administered 600mg nettle extract per day. The patients were quizzed for various symptomatic effects like emptying the bladder and need to push to urinate. The subjects under treatment did not report any other side effects.
Conclusion: Nettle extract helps in managing and relieving benign prostatic hyperplasia.
Nettle extract for prostate hyperplasia-6 month study
Study: A clinical study on effect of administration of 120mg nettle extract three times a day for 6 months on 620 patients was taken up. After the end of 6 months ultrasound was conducted to measure prostate size and serum testosterone levels were estimated. All the patients including the placebo group were included in the trial and were administered 120mg nettle extract three times a day for next 18 months. At the end of study the impact of nettle extract was evaluated by measuring the prostate size and quantifying the levels of hormone like testosterone and prostate specific antigen in blood.
Result : At the end of study 81% patients reported relief in lower urinary tract symptoms but no other side effects. The ultrasounds revealed marginal reduction prostate size and blood analysis indicated no change in testosterone levels.
Conclusion: Nettle extract for prolonged 6 month treatment is effective in treating prostate enlargement.
Nettle extract has 5 alpha reductase activity
Study: Nahata and Dixit reported an invitro method for screening various herbal extracts for 5 alpha reductase activity. This is an important enzyme that breaks testosterone to dihydrotestosterone and inhibition of this enzyme maintains high levels of testosterone in blood. A number of plant extracts including Nettle extract was used for in vitro biochemical reaction and utilization of substrate in presence of extracts was estimated.
Result: Nettle extract inhibited the enzyme 5 alpha reductase.
Conclusion: Nettle extract enhances the testosterone levels possibly by the arresting its bio conversion to dihydrotestosterone.
Ethanolic and petroleum ether extracts of Nettle help manage prostate hyperplasia in rats
Study : Ethanolic and petroleum ether extract of nettle root and one purified component of the extract (β-sitosterol) were administered to rats ( with induced prostate enlargement) at concentrations of 10, 20 and 50 mg per Kg body weight for 28 days. The only exception in this experiment was the concentrations of purified component used were 10 and 20 mg per kg body weight. At the end of study serum testosterone levels, prostate specific antigen and ratios of body and prostate weight were determined.
Results: All the Nettle extracts resulted in improved urine outflow and reduced the prostate size.
Conclusion: Nettle extract is effective in treating prostate hyperplasia in rats.
Lignans from nettle root bind to Sex hormone binding globulin, increasing free testosterone
Study: Multiple independent in vitro studies were conducted in 1990s to elucidate the mechanism of action of nettle extract. Prostate membranes were used in vitro in binding assays using various different extracts of stinging nettle.
Results: Nettle lignans ( polysaccharides) bind to sex hormone binding globulin and inhibit its binding to its specific receptor. Testosterone exists mainly as bound form with this globulin and only free testosterone is available to enter the cells. These lignans bind to the sex hormone binding globulin thus making free testosterone available in cells.
Conclusion: Nettle extract lignans inhibit binding of testosterone to sex hormone binding globulin and increasing the levels of free testosterone.
Nettle root extract helps in increasing the levels of testosterone by inhibiting the binding of testosterone to sex hormone binding globulin that in turn enhances the levels of free testosterone. In addition to this mechanism, in vitro enzymatic studies also indicate that components of nettle root extract arrest the activity of enzymes that bio convert testosterone to dihydrostestosterone hence increasing the levels of free testosterone. Human clinical studies show no adverse toxic side effects of nettle extract. Prostate hyperplasia can be reduced by oral ingestion of 120mg extract thrice a day for 6 months. Purified fractions of the extract have also been used in few studies and show positive influence in management of prostate enlargement. However, there are no studies on use of this extract along with common drugs and its interaction with drugs is not known. A daily dose ranging from 500-600 mg did not show any side effects and any higher dosages beyond these levels must be taken only after physician’s advice.
Nettle extract supplements can help enhance the testosterone levels and also help in managing benign prostate hyperplasia in older men. Declining testosterone levels in older men lead to reduced physical performance and vitality. Stinging nettle supplements can be very useful as it can address both the physiological problems faced by older men.