Stinging nettle (scientific name: Urtica dioica) is a medicinal plant with a wide range of health benefits. The plant is named “stinging nettle” because its stems and leaves have hairy structures called trichomes, which cause a stinging sensation on touching.
Stinging nettle is about 80 percent water and 5 percent protein. It contains numerous fatty acids and a variety of amino acids including glutamine, beta-alanine, leucine, phenylalanine and histidine.
It is also rich in bioactive nutrients such as polysaccharide lignans, glycosides and sterols. These nutrients affect the human body in several ways and help boost health.
Stinging Nettle is 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.
Medicinal properties of stinging nettle
Stinging nettle has been used to treat a wide variety of health problems ranging from cardiovascular diseases to cancer. It has been extensively used in traditional folk medicine to treat conditions such as:
• Muscle wastage
• Chronic skin eruptions
• Intestinal Worms
• Hair loss
• Prostate swelling
Stinging nettle is also found in many testosterone boosting supplements. Here, we will find out if it is effective in boosting testosterone and what scientific research says.
How does stinging nettle boost testosterone?
Stinging nettle is believed to boost testosterone by three mechanisms. It inhibits aromatase, which is an enzyme that converts testosterone into estrogen. Stinging nettle also inhibits 5a-reductase, the enzyme that converts testosterone into dihydrotestosterone (DHT). It binds with Sex hormone-binding globulin (SHBG), a protein, which binds to testosterone and makes it inactive.
What do the studies say?
Several animal and human trials have been conducted to understand how stinging nettle supplementation may impact testosterone levels. Here is a look at what some of these studies have revealed.
Study: Ameliorative effects of stinging nettle (Urtica dioica) on testosterone-induced prostatic hyperplasia in rats
This study was conducted to understand the effects of stinging nettle on benign prostatic hyperplasia (BPH) in rats induced by testosterone. The subjects were divided into various groups: one group received no treatment, the second received testosterone, the third received testosterone and drugs used to treat BHP and some received testosterone plus varying concentrations of stinging nettle root extract for 28 days.
The groups receiving stinging nettle had significantly higher testosterone levels compared to those receiving only testosterone treatment. The affect was attributed to inhibition of the enzyme 5a-reductase in the nettle groups (full study).
Study: Aromatase inhibitors from Urtica dioica roots
This study was conducted to find out if compounds extracted from stinging nettle could inhibit aromatase, an enzyme that converts testosterone to estrogen. The researchers isolated five different compounds from stinging nettle roots and mixed them each in a solution with biological material that contained aromatase.
Each of the compounds isolated from stinging nettle root was effective in aromatase inhibition (11-24 percent).
Study: Lignans from the roots of Urtica dioica and their metabolites bind to human sex hormone binding globulin (SHBG)
The study investigated the potential interaction of plants compounds known as lignans with human sex hormone binding globulin (SHBG), a protein that transports and stores testosterone and other sex hormones. This interaction is important to study because once SHBG is bound to testosterone, it cannot be used by the body.
The research involved isolating multiple lignans from stinging nettle root extract and testing them separately in a solution containing dihydrotestosterone and SHBG, one of the sex hormones.
- Except one, all lignans bound to SHBG. It resulted in less SHBG that could bind with DHT.
- 3,4-divanillyltetrahydrofuran was found to be the most potent lignan as it could prevent 95 percent of DHT from binding.
Study: Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study
The research was conducted to investigate the effects of stinging nettle on the symptoms of benign prostatic hyperplasia (BPH). It involved 558 patients of BPH. 287 patients were given stinging nettle extract, and 271 were given placebo for six months. After six months, the patients who received the placebo were switched to stinging nettle.
At the end of 18 months of medication, researchers found:
• Improvement in International Prostate Symptom Score (IPSS) and the maximum urinary flow rate (Qmax) with medication
• Serum Prostatic- Specific Antigen (PSA) and testosterone levels remained unchanged
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.
Stinging nettle dosage for increased testosterone
There are no recommendations for correct dosage of stinging nettle for increasing testosterone. However, most supplements recommend 250-750 mg.
Potential side effects of stinging nettle
Stinging nettle may cause some minor side effects such as sweating and an upset stomach. It is largely considered safe and well-tolerated, with very low toxicity.
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.
We don’t have enough conclusive evidence in support of stinging nettle’s efficacy as a testosterone booster. Most of the studies conducted on humans are in vitro, i.e., they have been performed on isolated cultures and not on humans themselves.
The only study that has been conducted on humans has failed to show any positive results. So, we cannot really call it a strong testosterone booster unless more scientific research is conducted.