3 minute read

Does obesity cause low testosterone?

By Joe Young | Medically reviewed by Dr Luke Pratsides

Obesity is a growing concern in men’s health. As of 2021, 26% of men in the UK are obese and 32% are overweight. This means that a staggering 58% are at risk of health problems like diabetes, sleep problems, heart disease, and stroke.

But what about the risk of low testosterone levels? 

Let’s find out. 

The link between obesity and low testosterone

Testosterone has a strong influence on a man’s health. It drives everything from muscle mass to bone density, to sex drive, and even mood. 

Similar to most aspects of your health - carrying extra weight minimises its performance. 

Excess fat makes your body convert more testosterone into oestrogen, the female sex hormone. Increased levels of estrogen lead to weaker erections, decreased libido, development of breasts, and further weight gain. This means someone with a waist circumference greater than 102 cm (40.2 inches) is at high risk of developing testosterone deficiency

Obesity also causes insulin resistance, where your body’s cells become blunt to insulin’s effects. It’s not only a primary driver of diabetes, but also low testosterone. Insulin resistance destroys the delicate balance of hormones in your body.

What does the research say?

There’s plenty of scientific evidence behind the link between testosterone and obesity. An in-depth study from the University of Buffalo looked at 25 obese and 25 lean males to see their testosterone levels. They were shocked to find that obese males aged 14 to 20 have up to 50% less total testosterone, furthering their risk of infertility as adults. You might think that low testosterone only affects older men - but this suggests this isn’t the case. 

Another study of 1,849 men found that 40% of obese men have low testosterone levels. The researchers also found that the risk of low testosterone increased with increasing body mass index (BMI). 

Thankfully, the effects can be reversed. Testosterone levels increase as you lose weight. Researchers have found that weight loss, whether by diet or surgery, increases testosterone significantly. One study suggests that even smaller degrees of weight loss in only mildly overweight men significantly increase testosterone levels.

Does low testosterone increase your risk of obesity?

The relationship goes both ways - low testosterone levels can also lead to obesity. Low levels of the hormone are associated with increased fat storage and reduced muscle mass. They’re also linked to energy imbalance, impaired glucose control, reduced metabolism, and less insulin sensitivity - all factors which could lead to weight gain. 

Low testosterone levels can also disrupt the finely-tuned balance between appetite hormones like leptin and ghrelin. This may cause an increase in appetite, leading to weight gain. 

Several long-term studies have shown that men with low testosterone levels are more likely to develop metabolic syndrome - the medical term for a combination of diabetes, high blood pressure (hypertension), and obesity.

Is testosterone therapy effective in treating obesity?

Testosterone treatments have shown amazing results for people with type 2 diabetes, with 34% of patients going into remission over an 11-year study. But what about its effects on your weight?

There’s evidence for replacement therapy leading to weight loss in obese people with low testosterone. One study concluded that testosterone therapy increases lean body mass, reduces fat mass, and produces sustained and significant weight loss, reduction in waist circumference, and BMI. 

In a study, obese men with low testosterone lost significant amounts of weight over time when given long-term treatment. On the other hand, the men who didn’t receive the treatment actually gained weight during the study.

The numan take

It’s a vicious cycle. If you suffer from obesity, you’re more likely to have low testosterone and vice versa. So break the cycle. Take action to address obesity and low testosterone before the conditions worsen.