STINGING NETTLE (root)
Stinging nettle (Urtica dioica) is an herb that has a long history of medical use, , especially for urinary tract problems. In addition to its anti-inflammatory properties, stinging nettle is a diuretic, and both of these characteristics make it a good candidate for prostate issues, including BPH, prostatitis and urinary tract symptoms (LUTS) associated with those disorders.
Laboratory studies have indicated that stinging nettle is comparable to finasteride (Proscar), a drug commonly used to treat BPH, in inhibiting the growth of certain prostate cells. Scientists have not yet determined why stinging nettle root has been shown to reduce symptoms of BPH, although there are several theories. One is that the supplement contains chemicals that have an impact on the hormones testosterone and estrogen, while another suggests the plant’s components work directly on prostate cells.
Stinging Nettle and BPH
In a six-month, double-blind, placebo-controlled, randomized comparative trial published in the Journal of Herbal Pharmacotherapy, researchers evaluated the effects of stinging nettle and placebo in 558 men who had BPH. The men were evaluated using the International Prostate System Score (IPSS), the maximum urinary flow rate (Qmax), postvoid residual volume, serum prostatic-specific antigen (PSA), testosterone levels, and prostate size. At the end of the six-month trial, 81 percent of men in the stinging nettle group reported an improvement in lower urinary tract symptoms (LUTS) compared with 16 percent of men in the placebo group.
In the stinging nettle group, the IPSS declined from 19.8 to 11.8, and in the placebo group it went down from 19.2 to 17.7. Peak flow rates improved by 8.2 mL/second in the stinging nettle group and by 3.4 mL/second in the placebo group. Postvoid residual volume decreased from 73 to 36 mL in men who took stinging nettle, but there was no appreciable change in the placebo group. The size of the prostate also decreased slightly in the men who took stinging nettle but not in those on placebo. At the end of the six-month trial, men who had been taking placebo were given stinging nettle, and both groups of men were followed-up at 18 months. Men who continued therapy showed a favorable outcome. (Safarinejad 2005)
In a randomized, double-blind, placebo-controlled multicenter study lasting one year, researchers evaluated the use of Bazoton uno (459 mg dry extract of stinging nettle roots) compared with placebo in 246 men who had BPH. After one year of intervention, the IPSS decreased significantly in the Bazoton uno group compared with placebo. The median Qmax rate increased and the median volume of residual urine decreased in the Bazoton uno group, but neither change was significantly different from those in the placebo group. The number of adverse events and urinary infections was fewer in the Bazoton uno group compared with the placebo group. The study’s authors concluded that Bazoton uno can be considered a safe option for men who have BPH, especially for reducing irritative symptoms. (Schneider 2004)
Stinging Nettle and Prostate Cell Growth
A German study investigated the impact of a 20 percent methanolic extract of stinging nettle roots on the proliferative activity of human prostatic epithelial and stromal (connective tissue) cells using a colorimetric test. The test showed that the stinging nettle extract had a concentration-dependent and significant antiproliferative effect on the epithelial cells during 7 days, but that the stromal cell growth did not change. Inhibition was time-dependent, with the maximum reduction (30%) in growth occurring on day 5 compared to the untreated control. The extract did not demonstrate any cytotoxic effect on cell proliferation. (Konrad 2000)
Stinging Nettle, BPH, and LUTS
An October 2010 study from Italy evaluated the use of a botanical combination formula (Pluvio®) containing high amounts of stinging nettle plus avocado and soya oil in men who were surgical candidates to treat lower urinary tract symptoms associated with BPH. One group of men took the natural supplement for six months while the other group took no supplement. After six months, men who had taken the stinging nettle combination had marked improvements in urine flow, quality of life, residual urine, and the need to urinate during the night (nocturia), all without significant side effects. Both PSA and prostate volume were not significantly affected, and no notable side effects were observed. (Bercovich 2010)
Stinging Nettle, Saw Palmetto, and BPH
In a recent clinical trial, 257 patients were randomized to receive 160 mg daily of saw palmetto plus 120 mg of stinging nettle (PRO 160/120) twice a day or placebo. The double-blind segment of the study was followed by an open control period of 24 weeks during which all patients were administered the PRO 160/120. Patients randomized to placebo showed a marked improvement in LUTS (as measured by the International Prostate Symptom Score) .The tolerability of PRO 160/120 was comparable to the placebo and the authors concluded that PRO 160/120 was clearly superior to the placebo for the amelioration of LUTS. (Lopatkin 2007)
In another study that also used PRO 160/120, a subgroup of 431 patients with early stage BPH was evaluated from a randomized, double-blind, multicenter clinical trial involving 543 patients. The men were randomly given a fixed combination of saw palmetto extract and stinging nettle root (PRO 160/120) or the 5-alpha-reductase inhibitor finasteride (Proscar). After 24 weeks, the mean maximum urinary flow rate increased by 1.9 mL/second in men who took PRO 160/120 and by 2.4 mL/second in the finasteride group. Men in both groups showed similar improvements in prostate size and in their values on the International Prostate Symptom Score. A safety analysis of 516 patients showed that more men in the finasteride group reported adverse effects than did those in the PRO 160/120 group. The authors concluded that the efficacy of PRO 160/120 and finasteride was similar and unrelated to prostate volume, but that PRO 160/120 had better tolerability than finasteride. (Sokeland 2000)
Stinging Nettle and Prostatitis
A prospective, randomized study was conducted to determine the therapeutic effect of saw palmetto and stinging nettle (ProstaMEV) and quercetin and curcumin (FlogMEV) extracts compared with the antibiotic prulifloxacin in men who had chronic bacterial prostatitis. A total of 143 patients were enrolled, and they were split into two groups: Group A (106 patients) received both prulifloxacin (600 mg daily) plus ProstaMEV and FlogMEV for 14 days; Group B (37 men) received the antibiotic only. After one month, 89.6 percent of men who received the herbal formulas had no symptoms of prostatitis compared with only 27 percent of the men in the antibiotic-only group. Six months after the intervention portion of the study ended, no patients in Group A had recurrent of prostatitis compared with two patients in Group B. The authors concluded that the association of saw palmetto, stinging nettle, quercetin, and curcumin extracts can improve the clinical efficacy of prulifloxacin in men who have chronic bacterial prostatitis. (Cai 2009)
Occasional mild side effects of stinging nettle may include stomach upset, rash, and fluid retention. Men who have BPH or suspect prostate problems should not self-treat with stinging nettle but instead consult their healthcare provider.
Bercovich E, Saccomanni M. Analysis of the results obtained with a new phototherapeutic association for benign prostatic hyperplasia versus controls. Urologia 2010 Oct 2; 77(3): 180-86
Cai T et al. Serenoa repens associated with Urtica dioica (ProstaMEV) and curcumin and quercitin (FlogMEV) extracts are able to improve the efficacy of prulifloxacin in bacterial prostatitis patients: results from a prospective randomized study. Int J Antimicrob Agents 2009 Jun; 33(6): 549-53
Konrad L et al. Antiproliferative effect on human prostate cancer cells by a stinging nettle root (Urtica dioica) extract. Planta Med 2000; 66(1):44-47.
Lopatkin N et al. Efficacy and safety of a combination of Sabal and Urtica extract in lower urinary tract symptoms—long-term follow-up of a placebo-controlled, double-blind, multicenter trial. Int Urol Nephrol 2007; 39(4): 1137-46.
Safarinejad MR. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. J Herb Pharmacother 2005; 5(4):1-11.
Schneider T, Rubben H. Stinging nettle root extract (Bazoton-uno) in long term treatment of benign prostatic syndrome (BPS). Results of a randomized, double-blind, placebo controlled multicenter study after 12 months. Urologe A 2004 Mar; 43(3): 302-6
Sokeland J. Combined sabal and urtica extract compared with finasteride in men with benign prostatic hyperplasia: analysis of prostate volume and therapeutic outcome. BJU Int 2000;86:439-442.