What is a Nanogram?
Nanogram is the chosen unit for measurement in the United States of America when measuring various hormones on blood tests, including testosterone. The range is from 250-350 nanograms per deciliter (ng/dl) on most labs, and up to 1000-1200 nanograms per deciliter (ng/dl) on most labs.
These ranges are what many Hormone Replacement Therapy (HRT) doctors use to determine if you are a candidate for replacement therapy.
A nanogram is 1, 1 billionth of a gram or 1/1,000,000,000 of a gram. 454 grams make 1 pound, so that tells you a bit of reference for how truly small a nanogram is. A deciliter is 1, 1 tenth of a liter, or 100 milliliters. Your Poland spring water bottle in your average vending machine is 1/2 a liter or 500 milliliters (ml). So, testosterone in men is measured in billionths of a gram per 100 milliliters (1/10th of a liter).