Finasteride

Finasteride is a prescription medication that treats hair loss and prostate problems in men. The medication works by blocking an enzyme called 5-alpha reductase, which converts testosterone into a more potent hormone called dihydrotestosterone, or DHT. By lowering DHT levels, finasteride helps hair grow back and reduces prostate size.

The FDA approved finasteride in two different strengths. The 1 mg dose treats male pattern baldness, sold under the brand name Propecia. The 5 mg dose treats benign prostatic hyperplasia, or BPH, sold under the brand name Proscar. BPH is a condition where the prostate gland becomes enlarged and makes urination difficult.

Finasteride belongs to a class of drugs called 5-alpha reductase inhibitors. The medication has been used safely by millions of men since the 1990s. Most men who take finasteride for hair loss see results within 3 to 6 months.

• Male pattern hair loss, also called androgenetic alopecia
• Benign prostatic hyperplasia, or enlarged prostate gland
• Reducing urinary symptoms caused by an enlarged prostate
• Lowering the risk of acute urinary retention in men with BPH
• Preventing the need for prostate surgery in men with BPH

Finasteride blocks the enzyme 5-alpha reductase, which normally converts testosterone into DHT. DHT is a powerful hormone that causes hair follicles to shrink and the prostate gland to grow. By reducing DHT levels by up to 70%, finasteride reverses these processes.

For hair loss, lower DHT levels allow shrunken hair follicles to recover and grow thicker hair. For BPH, the reduced DHT causes the prostate to shrink over time, which relieves pressure on the urethra. This makes urination easier and reduces symptoms like frequent nighttime bathroom trips.

For male pattern baldness, the typical dose is 1 mg taken once daily by mouth. For benign prostatic hyperplasia, the typical dose is 5 mg taken once daily. You can take finasteride with or without food. Your doctor will determine the right dose based on your condition and response to treatment. It may take 3 months or longer to see benefits for hair loss. For BPH, prostate shrinkage typically occurs over 6 to 12 months.

• Decreased sex drive or libido
• Difficulty getting or maintaining an erection
• Reduced amount of semen during ejaculation
• Breast tenderness or enlargement
• Testicular pain or discomfort
• Dizziness or feeling lightheaded
• Skin rash or itching

Most side effects are mild and improve over time. Serious side effects are rare but include depression, suicidal thoughts, severe allergic reactions, and male breast cancer. Some men report persistent sexual side effects even after stopping the medication. Contact your doctor immediately if you experience mood changes, breast lumps, nipple discharge, or difficulty urinating.

• Finasteride can interfere with PSA blood tests used to screen for prostate cancer
• Tell your doctor you take finasteride before any PSA testing
• Women who are pregnant or may become pregnant should never handle crushed or broken tablets
• Finasteride is absorbed through the skin and can cause birth defects in male fetuses
• No major drug interactions are known with common medications
• St. John's Wort may reduce finasteride effectiveness
• Do not donate blood while taking finasteride and for 1 month after stopping

Men taking finasteride should have regular blood tests to monitor prostate health and hormone levels. A PSA test, or prostate-specific antigen test, screens for prostate cancer and should be done before starting finasteride and regularly during treatment. Finasteride typically lowers PSA levels by about 50%, so your doctor will adjust the interpretation accordingly. Testosterone levels may also be monitored to ensure hormones remain in a healthy range. Rite Aid offers blood testing services with 200+ biomarkers, including PSA and testosterone, available twice yearly for $349 annually.