What is considered a low level of testosterone?

The normal testosterone level is 270 to 1070 nanograms per deciliter, and anything below this range is considered a low testosterone level, according to MedicineNet. It is necessary to determine if the low level is due to normal aging or a disorder.

Conditions that may cause low testosterone levels include obesity, type 2 diabetes, hormonal disorder, and liver or kidney disease, notes MedicineNet. Symptoms of low testosterone include low libido, infertility, emotional changes, change in sleep patterns, and sexual dysfunction. Testosterone level is at the peak at age 20 and starts declining after age 30. Treating low testosterone levels involve administering medications containing testosterone.