What is the age in which hypogonadism in males needs to be taken seriously?

Now: There are various causes of hypogonadism, but they all should be followed by a specialist.

Delayed puberty: Usually by 16 years old.

Treated after age 13: Usually boys aren't diagnosed with delayed puberty until they're at least 13. By the time they're 14, with little or no pubertal development, some may need a "jump start" with testosterone. It takes sometimes years to know if a boy is simply delayed or truly hypogonadal unless he has testicular failure.