Nettle extract is a natural agent that has consistently been shown to reverse prostate enlargement in European studies . In a study on prostate health, Hartmann et al (1996) concluded that nettle extract partially blocks an enzyme called 5-alpha-reductase. This enzyme converts testosterone to DHT (dihydrotestosterone) . They also found that nettle inhibits the binding of DHT to attachment sites on the prostate membrane.
Nahata and Dixit (2013) conducted a study on the 5-alpha-reductase activity of 11 herbs including stinging nettle (Urtica dioica) and also confirmed that nettle extract inbits 5-alpha-reductase. A petroleum ether nettle extract proved to be the most potent inhibitor of the enzyme, followed by the ethanolic and aqueous extracts. Out of the 11 herbs investigated in the study, stinging nettle was found to be the second most potent inhibitor, second only to Ganoderma lucidum. Results from a study by Moradi et al (2015) on rats with benign prostate hyperplasia were coherent with this and led to the conclusion that nettle had similar effect to finasteride which is used for treatment of prostatic hyperplasia widely (Cayatte et al 2006).
On the contrary, earlier studies by Rhodes et al (1993) showed that there is no evidence that nettle root extract interacts with the binding of radioactively labelled DHT to rat prostatic androgen receptors. Rausch et al (1992) also conducted a study which showed that nettle root extract had no effect on microsomal 5-alpha-reductase activity (Rausch et al, 1992). However, nettle extract shows 5-alpha-reductase inbitory activity in a concentration dependent manner (Hartmann et al, 1996). Hence, it is noted from their study that only high doses of a methanolic nettle extract inhibited the enzyme (ED50 14.7mg/ml).
The results of these studies suggest that at very low concentrations of nettle extract, the levels of DHT are not affected but as the nettle concentration is increased, it inhibits 5-alpha reductase and thereby interferes with conversion of testosterone to DHT. This results in a decrease in the level of DHT.
- Cayatte, C., Pons, C., Guigonis, J.M., Protein Profiling Of Rat Ventral Prostate Following Chronic Finasteride Administration: Identification And Localization Of A Novel Putative Androgen-Regulated Protein. Mol Cell Proteomic. 2006; 5(11):2031–2043.
- Hartmann R.W., Mark, M. and Soldati F., Inhibition Of 5 Α-Reductase And Aromatase By Phl-00801 (Prostatonin®), A Combination Of Py102 (Pygeum africanum) And Ur102 (Urtica dioica) Extracts, Phytomedicine. 1996; 3(2): 121-128.
- Moradi, H.R., Erfani, M.N., Fatemi, T.S.R., The Histological And Histometrical Effects Of Urtica dioica Extract On Rat’s Prostate Hyperplasia,Vet Res Forum, 2015 Mar; 6(1): 23-9.
- Nahata, A. and Dixit, V.K., Evaluation Of 5α-Reductase Inhibitory Activity Of Certain Herbs Useful As Antiandrogens,Andrologia. 2014 Aug;46(6):592-601.
- Rausch, U., Aumu¨ller, G., Eicheler, W., Gutschank, W., Beyer, G., Ulsho¨fer, B., Der Einfluss von Phytopharmaka auf BPH-Gewebe und Explantatkulturen in vitro. In: Rautishauser, G. (Ed.), Benigne Prostatahyperplasie III. Klinische und Experimentelle Urologie. 1992; 22:116–123.
- Rhodes, L., Primka, R., Berman, C., Vergult, G., Gabriel, M., Malice, M., Gibelin, B., Comparison Of Finasteride (Proscars), A 5a-Reductase Inhibitor, And Various Commercial Plant Extracts In In-Vitro And In-Vivo 5a-Reductase Inhibition. Prostate, 1993; 22: 43–51