Is Testosterone Really That Important? Yes, and Here’s Why

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Testosterone tends to be a hot topic, with plenty of ads pushing the miraculous, anti-aging benefits of testosterone supplements, while many medical experts warn of dangerous side effects.  

Understanding testosterone’s purpose is the first step to figuring out more about the hormone (and why some people think they need a little extra). So, what exactly is going on with testosterone?  

The real deal with testosterone 

The quick and dirty? Testosterone is a steroidal hormone that serves as the primary sex hormone in men and people assigned male at birth and is produced by the testicles (though the adrenal glands also contribute a small amount). Like other hormones, it is secreted into the bloodstream where it is carried throughout the body. 

“Testosterone is responsible for driving pubertal changes during male adolescence, such as development and maturation of the male sex organs, production of sperm, deepening of the voice, and growth of body hair,” says Dr. Jeremy Choy, a male reproductive endocrinologist who works at the Men’s Health Center at University of Washington Medical Center – Roosevelt. 

He also adds that testosterone is a driver of sexual function in adult men, promoting libido, erectile function and fertility — plus it’s a crucial element of maintaining muscle mass and bone density.  

Other ways that your body may respond to testosterone? Well, those charming tufts of ear hair and the extra nose fuzz that some men notice as they grow older can be blamed on decades of exposure to the hormone, as can male pattern baldness. 

When testosterone levels are out of whack 

When it comes to producing not enough testosterone, Dr. Bradley Anawalt, a hormone specialist and UW Medical Center’s chief of medicine, notes that it can get confusing for patients.  

Though there are many reasons why testosterone levels can be low — anything from being overweight to aging to having health issues like diabetes — hypogonadism is the term used when there is an actual deficiency in testosterone levels.  

Anawalt explains that, in usual circumstances, the man’s hypothalamus, a structure at the base of the brain, stimulates the pituitary gland to release two hormones, luteinizing hormone and follicle-stimulating hormone, that stimulate the testes to produce testosterone and sperm. 

“So, if you have a problem anywhere on that track, then you can get testosterone deficiency,” says Anawalt, “and those men may develop fragile bones due to osteoporosis or low bone density, muscle weakness, and decreased muscle mass. Their blood count may go down, and their sexual drive and function typically decline. There are real side effects of having testosterone deficiency.” 

When it comes to discussing testosterone levels that are too high, Choy thinks it’s important to distinguish between whether the levels are high due to endogenous overproduction (which is less common) or high because of an outside source, like hormonal supplementation.  

“In the latter case, we see adverse effects such as mood instability, acne breakouts and overproduction of red blood cells, which can increase a man’s risk of thromboembolic events [dangerous blood clots],” says Choy. “Too much testosterone can also drive the generation of too much estrogen, upsetting the balance between the hormones and causing problems with fertility, sexual dysfunction and even development of breast tissue.” 

Figuring out your testosterone levels 

When it comes to measuring testosterone levels, you’ll find that it’s not something that your doctor is going to routinely check — so you’ll want to let them know if you’re experiencing symptoms that could be associated with hypogonadism, like low libido or decreased energy. 

If you decide to test your levels with the blood test, check them in the morning when they are naturally at their highest. According to Anawalt, if levels are tested in the evening, 15 to 30% of the time they’ll be low in men with normal testosterone production — which leads to overdiagnosing testosterone deficiency. You’ll need to take two tests that show low levels to confirm the diagnosis. 

Heads up — there has also long been a struggle to make sure clinics and doctors are on the same page about what constitutes a “normal” level, which is why the Centers for Disease Control and Prevention (CDC) recently created a standardization program for testosterone because there was too much variance between clinical laboratories across the nation. This is why Anawalt recommends that if your testosterone is reported to be low, to ask your doctor if the measurement was done by laboratory that has been certified by the CDC.

Testosterone treatments and therapies 

Anawalt also notes that most people who come in thinking they have testosterone deficiency don’t need testosterone therapy, as there are usually other ways to fix their issue. Millions of men over age 40 have testosterone levels that are a little low, and it’s related to other health problems. 

For example, weight. As you gain weight, your testosterone levels tend to decline.  

“Weight reduction surgeries and medications that cause weight loss will help raise the testosterone levels in men that are overweight and have low testosterone. So, they don’t need testosterone per se, they often will benefit from weight loss alone,” says Anawalt. 

You don’t just throw testosterone supplements at the problem; you need to treat the real cause. And aside from weight, some other conditions and illnesses result in “turning off” the natural testosterone-creating process, so it’s important to consult with your doctor and make sure you understand the real source of the issue. 

So, what happens if you actually have testosterone deficiency? Well, luckily there are plenty of treatment options available that are approved by the Food and Drug Administration (FDA). You can take pills twice a day or even get an injection once a week or every two weeks. Another popular option is either a patch or a gel that can be directly applied to the skin daily — typically on the shoulders and upper arms. 

“Just be careful if you’re putting testosterone on your shoulder that you don’t rub the skin of a baby or the skin of a female because there are reports of the testosterone transferring to other people,” says Anawalt. 

Testosterone gel that does get transferred by mistake can sometimes cause unintended (and not-so-pleasant) consequences. Things like excess body hair growth in women, a deepening voice or interrupted menstruation cycles. If it rubs off on a child? It can cause premature puberty. 

How do women fit into all of this? 

Another interesting testosterone fact? Women do also have testosterone, though the ovaries and adrenal glands make theirs. They produce a lot less of the hormone than men, but still, it plays a significant role in their libido, their level of energy, their fertility and the health of their bones and muscles. 

Women can also experience low testosterone — especially as they get older — which is something that they should discuss with their doctor if they have concerns. 

Myth busting: The testosterone edition 

Curious about that thing your friend or your friend’s friend told you about testosterone? Same here. Enter: our experts. 

“I think the biggest myth is that testosterone is going to make you a better sex partner,” says Anawalt. Since most people consider testosterone to be the sex hormone, there’s this idea that if you take testosterone, you perform better and that sex will be better. “There’s this notion that if my testosterone levels are on the low end of normal and if I add more, I’ll be a much better lover — and that’s just not true, it’s a myth.” 

For Choy, the most important myth to debunk involves testosterone and increasing fertility.  

“Testosterone is indeed a necessary ingredient for sperm production, but the key is that the testosterone needs to be produced from the man’s testicles. Treating with exogenous testosterone [from supplements, etc.] will suppress that testicular testosterone production, leading to infertility,” he says. 


What have we learned? Testosterone is a bit complicated. It doesn’t just affect men; it can be too high or too low — but in different kinds of ways, and there are a variety of treatments you can look into with the help of your doctor. 

So, maybe now that you are armed with a little extra information about testosterone, you can take the latest flashy testosterone supplement advertisement with just the tiniest grain of salt.