Propecia is a brand of finasteride (1mg) developed by international manufacturer and distributor of pharmaceuticals, Merk & Co. Propecia is one of two medicinal products licensed by the Medical Health and Regulatory Authority (MHRA) and approved by the Food and Drug Administration (FDA) for the safe treatment of hair loss in men over 18 years.

Propecia is an oral tablet whose key ingredient, finasteride, is a clinically proven inhibitor of type II 5 alpha-reductase – the enzyme that converts testosterone to dihydrotestosterone (DHT). DHT is the known cause of male pattern baldness in genetically predisposed men and it also contributes to the formation of benign prostatic hyperplasia (BPH). Finasteride is prescribed at varying dosages to treat both conditions.

Merck & Co obtained FDA approval in 1997 for finasteride (1 mg) for the treatment of male pattern baldness, which it marketed under the brand name Propecia.

A 5-year clinical study of 279 men saw 9 of 10 achieve visible results. Some 48% experienced hair regrowth and 42% stopped losing their hair. Nearly 70% of men who took Propecia regrew hair, as measured by hair count. All of the men in the study who were not taking Propecia lost hair. Less than 2% of users experienced mild side effects.

According to Merck & Co, reported side effects include breast tenderness and enlargement, depression, decrease in sex drive that continued after stopping the medication, allergic reactions including rash, itching, hives, and swelling of the lips, tongue, throat, and face, problems with ejaculation that continued after stopping medication, testicular pain, difficulty in achieving an erection that continued after stopping the medication, male infertility and/or poor quality of semen, and, in rare cases, male breast cancer. In men taking finasteride at five times the dose of Propecia, there may be an increased risk of a more serious form of prostate cancer.

Merk & Co advises those prescribed Propecia to tell their doctor if they have any side effects. The company also advises that Propecia can affect a blood test called PSA (prostate-specific antigen) for the screening of prostate cancer. Users should tell their health care provider that they are taking Propecia if they have a PSA test.