Why Does Testosterone Decrease In Men

The simple science of testosterone beyond just building muscle, beyond all the things we hear about, and a little bit more, and how it works more so with your brain than just other parts of your body. I want to explain in this article what really happens, when you have that natural decline in testosterone, say after age 30 or so. I  want to explain and really have you understand what’s happening hormonal, why things shut down. Because I think once there’s an understanding, there a lot of things, just start to make more sense.

I want to start out by talking about something called HPGA – the hypothalamic pituitary gonadal axis –  it’s a mouthful, so we’re just going to refer to it as the HPA axis. Basically, it’s super complex, but I’m going to make it simple. It comes down to three parts of your body: your hypothalamus, your pituitary, which is both in your brain, and, of course, your testes. Now, the production of testosterone starts with the hypothalamus. The hypothalamus creates something that’s called GnRH (Gonadotropin-releasing hormone), it’s a hormone and that hormone triggers the pituitary – another portion of your brain – to create two hormones that are called luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Those two hormones LH and FSH are absolutely imperative, when it comes down to creating testosterone. Because what they do, is after the pituitary gland has created them, as they travel way on down from the brain down into your loins, and into the testes, where they actually are combined with cholesterol to ultimately produce testosterone and other sex hormones. They combined with that cholesterol in these things called Leydig cells and from there you are creating testosterone. You’re also creating some other hormones, you’re even creating progesterone, you’re even creating some of these other things that affect your energy levels. But for now, we’re going to focus mainly just on testosterone.

Now once that LH and FSH are down in the testes getting converted into the proper hormones, it’s important to know what happens. The LH combines with cholesterol, that we consume, and cholesterol that are created to create that testosterone; while the FSH combines of cholesterol and foods that we eat to ultimately create the sperm count. They work hand in hand. Obviously, we need testosterone; we need a libido, we also need the sperm count for simple procreation reasons. That’s the purpose of testosterone in the first place. So that’s how that really works down there. Without those Leydig cells that allow that conversion to happen, you just have LH and FSH floating around through the body with nothing ever happening.

Now, another thing that’s important to know is that your brain isn’t always producing that GnRH. We have to take special care of our brain, it’s way more important than we think. The hypothalamus that is producing that GnRH is only producing it and pulses. A lot of times we hear that testosterone levels are higher in the morning. Well, it’s mainly because our brain is producing a pulse of GnRH usually first thing in the morning. What’s interesting enough is that it doesn’t just go with a time of day, it is also going to the circadian rhythm when you sleep, but also can go with a time of the year. Interestingly enough, GnRH and testosterone levels are usually higher in the springtime and make sense. When we think about it from an evolution standpoint, why would we want to be procreating in the wintertime, when in some regions it’s absolutely sub-zero and barely survivable. So as it starts to get warmer, of course, then our brain – not our testes – but our brain senses that it’s time for more testosterone. I think, the fixation has to come off of testosterone in general and think more about brain health, because our brain needs to realize that it’s time to produce testosterone. So as long as we protect that with a golden sword and really think about it, then we can be well on our way to having better testosterone levels.

Ok, so it’s all fine and dandy now, right? I got to take it one step further, because you know me, I’m always throwing a wrench in things throwing more science and making it super complicated, because that’s just the way I roll. But, anyway, it goes down to one more thing. Then we go into what is called DHT. DHT is dihydrotestosterone. It is the actually usable form of free testosterone. When it comes down to building muscle, when it comes down to growing a beard, when it comes down to having a sex drive, when it comes down to getting that six-pack, when it comes down to that DHT. Well, news flash for you DHT or that free form of testosterone only makes up about two percent of the overall testosterone, that you’ve gone through this entire process to create. Only 2%t if you’re lucky. The other 98% is bound to something called the sex hormone-binding globulin. Basically what that SHBG does is it locks that testosterone within the sex hormone world, creating testosterone for later, creating cortisol, creating different progesterone, creating pregnenolone, another hormone that creates other hormones. So, basically, we’re left with a small 2%. Well, as our levels of testosterone decline, you can imagine how that 2% gets even smaller and smaller and smaller. So that precious 2% that we’ve got to build muscle, or to have a sex drive, or to have the energy, or to have strong bones, declines and declines with age, and it becomes more precious.

Now, another thing to note, that’s pretty interesting, is something called a negative feedback loop. When you have enough testosterone produced as a safety mechanism not to produce too much, your brain recognizes it. It’s got what are called androgen receptors. These androgen receptors see that you have enough testosterone floating around and it says: “Okay, brain, don’t produce any more hormones, just create testosterone. Basically, we have enough testosterone, don’t create too much, we don’t want to cause a problem.” That is called a negative feedback loop. The brain is very smart, you can’t outsmart your brain, that’s why those, that are using exhaustion testosterone, usually have an issue with getting their natural levels back up to park, because that negative feedback loop is artificially disrupted. Well, that can also happen with aging at a different level.