Low Testosterone in younger men is increasingly common. Meanwhile, some 35% of the U.S. population suffers from metabolic syndrome, defined as high blood sugar (but pre-diabetic), excess weight around the waistline, hypertension, high cholesterol and/or high triglycerides.
It turns out that these two conditions are not only linked, but that each creates the environment necessary for the other.
Here’s how it works.
Low Testosterone Leads To Metabolic Syndrome
Testosterone shifts the body’s composition toward more muscle and less fat. The opposite happens when testosterone is too low: the body shifts its composition in favor of fat storage, rather than muscle building.
There is also an inverse relationship between high cortisol (the stress hormone) and testosterone: as cortisol goes up, testosterone goes down. (In other words, if you’re chronically stressed all the time, it can lower your testosterone levels.) High cortisol encourages metabolic syndrome all by itself, since one of its main jobs is keeping your blood sugar high enough to deal with the perceived stressor. Unused glucose has to get stored… and it gets stored as triglycerides, packaged into LDL, and shuttled out into the peripheral tissues, where it gets deposited as fat.
Testosterone also increases the production of Nitric Oxide (a vasodilator) by the blood vessels. This means adequate levels of testosterone help to maintain healthy blood pressure… and therefore, low levels of testosterone can contribute to hypertension.
One more chicken-or-egg problem: symptoms of low testosterone include depression and fatigue. If you’re feeling low, it’s hard to muster the motivation to work out and diet. This, of course, means more weight gain and worsening metabolic markers.
Metabolic Syndrome Leads to Low Testosterone
In normal physiology, the pituitary gland secretes the hormone LH, which signals the testes to make testosterone. But high glucose in the blood will lower LH secretion. So effectively, high blood sugar (one of the characteristics of metabolic syndrome) means less LH, which means less testosterone.
Another characteristic of metabolic syndrome is excess weight, or more fat. Fat cells contain an enzyme called aromitase, which converts testosterone into estrogen. So the more weight you carry, the more your body will take the testosterone you do make and turn it into estrogen. Symptoms of low testosterone and of high estrogen levels in men are quite similar.
Hypothyroidism can cause weight gain and high cholesterol levels (characteristics of metabolic syndrome), too. How this is relevant: the active thyroid hormone, T3, combines with Vitamin A to produce the parent of testosterone (pregnenolone). Therefore, if your metabolic syndrome is secondary to hypothyroidism, you will lack the building blocks required to make testosterone.
What to Do About It
According to this study, and many others, physiologic testosterone therapy (gel or injections) can reverse metabolic syndrome. (A word of caution here: in my experience, especially men who have metabolic syndrome require the addition of a medication that inhibits the aromitase enzyme in the fat cells, along with testosterone therapy. This prevents the sudden high dose of testosterone from converting into estrogen, and landing you back where you started.)
Metabolic syndrome and low testosterone are self-reinforcing. Testosterone therapy for a period of time is one way to break the vicious cycle of low testosterone leading to metabolic syndrome, leading to even lower testosterone.