Summary: Not essential for boosting testosterone levels although can undoubtedly 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.
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 stinging nettle because the stem and leaves possess hairy structures called trichomes that cause a stinging sensation on touch.
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 humans show promising signs that nettle extract can help in managing prostate enlargement, relieving the UTI symptoms and increasing testosterone levels. Important clinical and animal studies on the impact 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 an 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: Clinical research on the effect of 120mg nettle extract taken three times a day for six months on 620 patients was taken up. After six months, an ultrasound was conducted to measure the 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 the next 18 months. At the end of the 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 the study 81% of patients reported relief in lower urinary tract symptoms but no other side effects. The ultrasounds revealed limited 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 in-vitro method for screening various herbal extracts for 5 alpha-reductase activity. This is an essential enzyme that breaks testosterone to dihydrotestosterone, inhibition of this enzyme maintains high levels of testosterone in the blood. Some plant extracts including Nettle extract were used for in vitro biochemical reaction.
Result: Nettle extract inhibited the enzyme 5 alpha reductase.
Conclusion: Nettle extract enhances the testosterone levels by arresting its bioconversion 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 of body weight. At the end of the study, serum testosterone levels, prostate-specific antigen, and ratios of body and prostate weight were determined.
Results: Nettle extract 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 the 1990s to elucidate the mechanism of action of nettle extract. Prostate membranes were used in vitro in binding assays using various 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 a 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 converts testosterone to dihydrotestosterone, 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 six months. Purified fractions of the extract have also been used in a few studies and show positive influence in the management of prostate enlargement.
However, there are no studies on the 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 getting a physician’s advice.
Nettle extract supplements can help enhance testosterone levels and also assist in managing benign prostate hyperplasia in older men. Declining testosterone levels in older men can lead to reduced physical performance and vitality. Stinging nettle supplements can be beneficial as they can address physiological problems faced by older men.