What are the signs that puberty is beginning?

Last updated on March 2, 2022


Are there any signs that signal puberty is near or very close to the beginning? Or are the signs just inside the body?


Technically, puberty is when the sex hormones (androgens for boys and estrogens for girls) begin to rise in the bloodstream. You can’t see the rise directly, though it can be measured in a blood test, but you can eventually see the changes triggered by the rise. It usually takes about a year before external signs begin to be seen.

For boys, these external signs are typically seen somewhere around age 11. They can show up as early as 9 or as late as 14. If they show up before 9, then that is considered to be a problem called precocious puberty. If they show up after 14, that is considered late. While it might not be a problem, there are some serious conditions that can cause puberty to be late and that has to be examined and ruled out.

The first external sign of puberty is a swelling of the testicles as they start to grow bigger. This in turn causes the scrotum to swell and often it takes on a redder tint as the blood flow to that area begins to increase. Most boys miss this change because it is gradual and not dramatic.

The second external sign is spontaneous erections. This again is often overlooked because the penises of young boys often get stiff. What changes is that the penis swells in size and the stiffness gets harder. Sometimes a guy notices because it gets uncomfortable under the clothing.

The third external sign is the beginning of body hair. Most often it is hair forming at the base of the penis. This is enough of a difference from the usual state of things that most boys notice this change. By this time they are usually halfway through stage 2 of development.

A fourth sign is the ejaculation of semen. This one is hard to ignore, but only about half of all boys start ejaculating in stage 2. Many boys don’t start ejaculating until they reach stage 4.


I think I’m a late bloomer. I’m 15 and a half and still have not hit puberty. I’m 5”3” and weigh 81 pounds. Do you think I will end up tall or short?


I can’t answer how tall you will be. We first must address why you haven’t started developing. I’m assuming that you don’t have any of the starting signs. If this is true, then you need to see your doctor for an evaluation. Among the things the doctor should do is a blood test to see where your hormones are at. If the hormones are off, you’ll be sent to an endocrinologist (a specialist in hormones) to see what is going on and what needs to be done to correct the problem.