The big picture: PSA (Prostate-Specific Antigen) is a protein produced by both normal and malignant cells of the prostate gland. It's most commonly used as a screening tool for prostate cancer. Elevated levels A can indicate prostate cancer, but they can also be a sign of benign conditions like prostatitis (inflammation of the prostate) or benign prostatic hyperplasia (BPH, enlargement of the prostate).

There are two major forms of PSA: Free PSA and Complexed PSA.

Free PSA circulates in the blood unbound to other proteins. A lower ratio of free PSA to total PSA can sometimes indicate a higher risk of prostate cancer.
Complexed PSA is bound to blood proteins and makes up the majority of total PSA.

Enter finasteride and dutasteride: These medications, commonly prescribed for hair loss, are part of the 5-alpha-reductase inhibitors class. They inhibit the enzyme 5-alpha-reductase responsible for converting testosterone into dihydrotestosterone (DHT), a hormone linked to prostate enlargement. Reducing DHT levels, these drugs effectively reduce the prostate size, leading to a significant decrease in PSA levels by approximately 50% or more within a six to twelve-month timeframe.

But there's a catch. Reduced PSA levels may obscure the detection of prostate cancer. This necessitates a modified diagnostic approach, where the normal PSA threshold is halved to trigger further investigation. Additionally, these drugs influence PSA velocity (the rate of PSA level changes) and PSA doubling time (the period for PSA levels to double). Slower PSA velocity and longer PSA doubling time are generally seen as favorable signs, but on these medications, these metrics need to be interpreted cautiously.