Testosterone Levels
Testosterone levels are measured in Nanograms per deciliter (ng/dl). A Nanogram is a very small amount. There are 1000000 Nanograms in 1 milligram. There are 1000 milligrams in a gram. There are 1000 grams in a kilogram and there are 2.2 pounds in a kilogram hence a Nanogram is less than 36 trillionths of an ounce!
A deciliter is one-tenth of a liter. Hence a deciliter is about 3.814 fluid ounces.
Here are some testosterone levels in healthy males.
Age
Testosterone Level (ng/dl)
0-5 months
75-400
6 months-9 years
7-20
12years-13years
7-800
14years
7-1200
17years-18years
300-1200
25years
270-1070
35years
257-1017
40years
243-963
50years
216-856
70years
162-642
There are a few points that need to be emphasized:
(i) At any age, there is a great range of testosterone levels that are regarded as 'normal'.
(ii) Testosterone levels are high in the first few months of life.
(iii) Testosterone levels are low until sometime from about 11 years old until 15 years when puberty sets in.
(iv) During the late teenage years, testosterone levels are the highest most men ever experience.
(v) From ages 20 years - 30 years testosterone levels are pretty constant in the range 270 - 1070.
(vi) After age 30 there is approximately a 1% decrease per year. 