What are the Average Testosterone levels by Age?

Testosterone levels are typically measured in nanograms per deciliter (ng/dL), and according to Mount Sinai, a healthy testosterone range is between 300 to 1,000 ng/dL. When teen boys are at their peak, at about age 19, they can have testosterone levels of 300 ng/dL and higher, with levels staying in that range until they hit their thirties, when levels may begin to decline.
According to studies, average men’s testosterone levels by age are as follows:
20 – 24-year-old males – 409 – 558 ng/dL
25 – 29-year-old males – 413 – 575 ng/dL
30 – 34-year-old males – 359 – 498 ng/dL
35 – 39-year-old males – 352 -478 ng/dL
40 – 44-year-old males – 350 – 473 ng/dL
According to another study, there’s been a consistent decline in testosterone levels in general over the last several decades and a 20% decline in young adult men. Currently, a sign of low testosterone in men is under 300 ng/dL.
The fact is that labeling any hormone level as normal is fruitless. Studies are meant to provide insight, but they don’t tell you what’s best for your personal situation. Normal levels of any hormone don’t mean the patient won’t have symptoms, as receptor site resistance, among other factors, can cause symptoms despite normal levels.