Medically reviewed by Neka Miller, PhD on March 27, 2020. Written by Caitlin Boyd. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
Every guy needs some fat – even if you’re Dwayne “The Rock” Johnson. But too much body fat, and your total and/or free testosterone levels may plummet – putting your health at risk on several fronts. In fact, there is a wealth of evidence that obesity is negatively correlated with testosterone levels. One study, for example, found that compared to men with a healthy weight, obese men were more than 8x as likely to have a low testosterone level.
And obesity holds the title as the most effective predictor of low testosterone in men – out of many possible risk factors.
As to why that’s the case? There’s actually a number of reasons why obesity contributes to low testosterone levels, but here’s a major one: fat cells, scientists have discovered, have a high amount of a particular enzyme (molecules that speed up chemical reactions) named aromatase. Aromatases have an interesting job description: basically, they’re tasked with building estrogen out of testosterone molecules (estrogen is the main female sex hormone, though men need this hormone, too – albeit in much smaller amounts).
So when a guy starts gaining weight from extra fat tissue, he’s got more and more aromatases converting his testosterone into estrogen. And thus, his testosterone levels will begin to fall. (Under healthy conditions, aromatases convert only a small amount of your testosterone to estrogen so you have just the right amount of estrogen – not too little or too much.)
Plus, abdominal fat is known to produce especially large amounts of aromatases – so it can be particularly devastating for a man’s testosterone levels if his extra pounds tend to gather in this part of his body.
Remember, though, that there’s more than one reason why too much fat can cause your testosterone levels to drop. Aromatase, in other words, is only part of the story.
In this guide, we'll explore the relationship between testosterone and weight gain, so you can better understand how one's testosterone level is impacted by weight changes. If one's testosterone level is out of balance, a healthcare provider may recommend testosterone therapy to increase the body's testosterone concentration.
In men, testosterone is made by the testes whenever certain regions of the brain – the hypothalamus and pituitary glands – receive signals from your body that more testosterone is needed. These glands then send a chemical message to your testes – which respond by ramping up production of testosterone.
However, obesity can throw a wrench in this whole process – and the wrench, in this case, is estrogen. In short, there is evidence that estrogen can lower testosterone production by triggering signals to your hypothalamus and pituitary glands that tell your brain you don’t need anymore testosterone.
And with drastically reduced testosterone levels, the motivation to hit the gym – and regularly get a good workout in – can diminish. Thus, in the words of one group of researchers, a “vicious circle” comes into play: obesity reduces testosterone through the conversion of testosterone to estrogen – and by estrogen’s signaling effects on your brain – and subsequently, the lack of motivation and energy to exercise further fuels obesity. This cycle can then repeat itself, over and over again – seriously jeopardizing your health and metabolic balance.
Suppose you are overweight or obese and have low T levels – as determined by the Everlywell Testosterone Test, for instance. What can you do to raise your T levels?
One solution: strive to lose some weight.
Weight loss, it turns out, boosts your testosterone levels. In fact, if you’re overweight (or obese) and have low T levels, taking off some of those pounds is one of the best things you can do to get higher T levels. This makes sense, of course, given the direct effects obesity has on testosterone. When you lose fat tissue, you’re interrupting the aforementioned “vicious cycle” – and that’s why the more pounds you drop, the higher your testosterone levels will climb. Also, you’ll get that testosterone boost regardless of how you’re losing weight: dieting, regular exercise, and bariatric surgery can all elevate testosterone levels by eliminating testosterone-destroying fat.
(Generally speaking, resistance exercise – like weightlifting – is the best kind of exercise for increasing your hormone level when it comes to testosterone, but you need to keep it up for at least 6 months to see a significant difference.)
And with a higher, healthier level of testosterone in your body, you can experience many improvements in your well-being. For example, some men suffer from erectile dysfunction because of low testosterone levels – and in one study, men who lost 15% of their body weight witnessed significantly improved erectile function.
If weight loss can increase one's testosterone level, then is the opposite also true? In other words, does testosterone make you lose weight? Evidence suggests that this is indeed the case among men experiencing testosterone deficiency: testosterone therapy among men with hypogonadism can lead to reduced fat mass, weight, waist circumference, and BMI.
You face an increased risk of low testosterone if you are overweight or obese. And under such circumstances, your body can be thrown into a destructive cycle where lower-than-normal T levels cause greater weight gain – which, in turn, drops your T levels even further (thus continuing the cycle).
Testosterone levels can be boosted in some cases, however, by lifestyle modifications involving weight loss – and in general, you’ll get higher T levels the more pounds you lose. So if you are overweight or obese – and a testosterone test reveals that you have low T – your healthcare provider may recommend a weight loss strategy as the ideal way to elevate your T levels.
In some cases, testosterone replacement therapy may also be recommended by a healthcare provider to address a serious hormone imbalance in the body related to testosterone.
Finally, keep in mind that if you are experiencing low testosterone symptoms, talking with your healthcare provider is a great step to take so you can learn what action steps they recommend for you.
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