But you don’t have to experience the negative symptoms that come with hormone declines. At its peak, during your adolescent years, a normal range for your testosterone is anywhere between 300 and 1,200 ng/dL (4). That’s when we start to check your hormone levels," McDevitt says. It helps men develop during puberty, and as they age, it plays a critical role in helping control fat levels, cholesterol, and glucose levels (1). "Estrogen is a proliferative hormone, meaning it likes to get cells to grow. Just like it can be too low, your testosterone can also be too high, and that’s equally problematic (8). "Honestly, a low libido is one of the least heard symptoms," McDevitt says. The designation of "healthy range" for testosterone levels depends on age and laboratory assay. As males age, their testosterone levels may decline by up to 2% annually after age 30 years. Learn more about testosterone levels by age, as well as symptoms and management tips for abnormal testosterone levels. Women experience the most dramatic shift during perimenopause and menopause, when estrogen and progesterone levels drop significantly. When levels decline, men often notice decreased muscle mass, increased belly fat, and difficulty maintaining strength despite consistent training. Testosterone levels decrease approximately 1-2% per year after age 30, according to the American Urological Association. Estrogen dominance, where estrogen levels are high relative to progesterone, can also contribute to these changes. Studies show that testosterone therapy for women with documented deficiency can meaningfully improve sexual function. While fluctuations are natural, recognizing when levels fall outside the normal range can help prevent unwanted symptoms and long-term health complications. These strategies help maintain testosterone levels in men by age and slow down natural declines. Normal free testosterone levels ensure optimal performance in physical and mental health. To determine testosterone levels in men by age, a blood test is required. For men with clinically low testosterone levels, medical treatments may be necessary. However, free testosterone levels are often a more accurate indicator of hormonal health since this fraction of testosterone is biologically active and readily available for the body to use. If your testosterone levels are declining, evidence-based treatment can restore energy, body composition, and quality of life.