Understanding Prostate-Specific Antigen (PSA) Levels by Age Prostate-specific antigen (PSA) is a protein produced by the prostate gland. While it is often used as a screening tool for prostate cancer, "normal" levels are not a single fixed number; they naturally increase as you age due to the prostate's gradual growth. Typical PSA Reference Ranges by Age

Vigorous exercise, bike riding, or ejaculation within 48 hours of the test.

Doctors often look at how quickly levels rise over time rather than a single snapshot. For example, a rise of more than 0.35 ng/mL in one year may prompt a closer look, even if the total number is within the "normal" range.