Blackmores Proserencontains the extract of the herb Serenoa at the recommended dosage used in published clinical trials. These trials showed the extract used in Proseren provides effective relief from the troublesome symptoms of medically diagnosed Benign Prostatic Hypertrophy (benign enlargement of the prostate) such as frequent urination, hesitancy, impairment of stream and nocturia. The mechanism by which serenoa works is not fully understood but most likely involve inhibition of the enzyme 5-alpha reductase and also binding to androgen receptor sites in prostate cells. The berry fruits of serenoa are rich in free fatty acids and a mixture of sterol compounds, including beta-sitosterol and stigmasterol (phytosterols). Although investigation to determine the exact mechanism of action is ongoing, these components are considered to be the pharmacologically active compounds in serenoa, and their levels are standardised in quality preparations. The free fatty acids may help to balance the often abnormal lipid ratios found in the prostate and seminal fluid of some benign prostatic hypertrophy patients. Clinical trials have confirmed the beneficial effects of serenoa for the relief of symptoms of enlarged prostate conditions. May be of assistance for the temporary relief of all major symptoms and signs of BPH including urinary frequency, nocturia, flow rate, dysuria and residual urine volume.