What is testosterone?
Testosterone is a hormone that’s critical for development on many levels: sexual development, muscle development, bone growth, cardiovascular development, growth of facial hair, and many more.
Testosterone is classified, somewhat confusingly, as an androgenic hormone, meaning a hormone we associate with men. But there are “male” hormones in women and “female” hormones in men. That said, testosterone is considered the most important “male” hormone. In men, it’s produced mainly in the testes; in women, it’s produced in the ovaries, and peripheral tissue; and in everyone, it’s produced in the adrenal glads.
It’s also an anabolic hormone, which means “building up” (as opposed to catabolic, which means “breaking down”). Testosterone builds up proteins. If you’ve heard the term “anabolic hormone” before, it might be because you’ve heard about the abuse of anabolic hormones by bodybuilders and professional athletes. But it’s a neutral, medical term.
Hormones are substances that are secreted in one area of the body and move into action and processes in another area of the body. So testosterone is produced in the testes or ovaries or adrenal glands and then it goes into the bloodstream. There are testosterone receptors all over the body, so it attaches to those receptors, wherever they are. There, it sends a signal for muscles to grow, or for cardiac contraction, or for brain function, and so on.
Most people associate testosterone with sex drive or muscle growth, and it is very important for both of those. But lesser known is that virtually every organ system in the body has testosterone receptors. The highest concentration of testosterone receptors, it might surprise you to know, is in the heart!
Testosterone has essentially the same functions in most people, irrespective of gender, sex, or gender identity. The real difference isn’t the function, it’s the concentration of testosterone from person to person. For example, during adolescence, the typical teenage boy will have extremely high levels of testosterone. These high levels are behind all the sexual and growth characteristics we generally associate with teenage boys. When one of those boys becomes an adult, his testosterone levels will plateau or decrease.
There’s a lot of fear around testosterone, even though it’s essential for every system in the body. Most of this fear is unwarranted, and a lot of it comes from hearing stories of testosterone abuse. I liken it to taking Tylenol: If you have a headache and you take two Tylenol, your headache goes away. If you take sixty, you need a liver transplant!
Overuse of any substance, including over-supplementing with those produced naturally by the body, will bring health troubles. But we shouldn’t be afraid of testosterone; after all, it builds our bodies, and we need it to live. Instead, we should start to understand it, be aware of our testosterone levels, and give care – in conjunction with an Age Management doctor – when needed.
This is the first in a series of easy-to-read, brief posts on testosterone from Dr. Mike Carragher.
Next up: How do I know if I have low testosterone levels?