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Low Testosterone Cause Weight Gain in Guys?

There are numerous factors that affect weight, and can cause either weight gain or loss. Diet and exercise are mainly responsible for causing changes in the body, in terms of weight and body composition. However, it is increasingly apparent from the results of various clinical studies that hormonal and chemical changes in the body are significant factors in weight control.

Low Testosterone and ObesityChemical imbalances can cause sudden or unexpected changes in weight, and may indicate an underlying health problem, of which weight change is merely an unwanted side effect. Numerous studies in recent years have focused upon the relationship between testosterone levels in men, and weight gain.

This article looks at the links between obesity, metabolic syndrome, body composition and low testosterone levels. Research is also suggesting ways in which both obesity and testosterone levels can be treated, in ways that positively impact both.

What Causes Lowered Levels of Testosterone?

Low Testosterone levels in the body can be due to a number of factors. In general, men go through Andropause from their 30s onwards, which is a decline in testosterone production as they age. This is a natural and progressive reduction in testosterone levels. Low testosterone levels can also occur due to a deficiency of minerals, especially zinc, as well as stress, elevated cortisol production, reduced production of DHEA, overtraining, head or gonadal trauma, or abdominal fat accumulation and insulin resistance. Some recent studies have even found that fatherhood causes a decrease in testosterone levels.


Studies have in recent years drawn a correlation between low testosterone levels in men and obesity. But, does low testosterone cause weight gain in men, or does a man being overweight lower his testosterone levels? Well, studies are beginning to suggest that the answer is both, making it a vicious cycle that can make it much harder to lose weight and to boost testosterone levels in the body.

Obesity Causes Decreases in Testosterone

Fat cells metabolize testosterone to estrogen, lowering testosterone levels. Therefore, if the body has significantly more fat cells, such as in an obese body, testosterone could be metabolized much faster by the body, leading to lower testosterone levels. Studies are supporting this correlation between increased body fat and reduced testosterone levels.

In a 2006 study (Source) on more than 2,100 men aged 45 and older, obese men were 2.4 times more likely to have low testosterone compared to those at a healthy weight. Studies also show that as Body Mass Index (BMI) increases, there is proportionate reduction in testosterone levels. The reverse is also true; as weight is lost by obese patients, especially due to exercise, testosterone levels rise again.

In a study published in Obesity Research, researchers measured testosterone levels in middle-aged obese men. Divided into two groups, one group underwent a 16-week weight-loss program while a control group did nothing. The weight-loss group lost an average of 45 pounds and had significant increases in testosterone levels, suggesting that treating the weight problem had a significant impact upon the endocrinology of the body.

A review of four relevant studies found that;

obesity is a major cause of low testosterone levels’ with Hypogonadism, or low levels of testosterone, being ‘found in 75% of men considered very obese (BMI >40 kg/m2).


Obesity seemed to be linked with low testosterone levels in men of all ages studied. Finally, and most significantly, it was concluded that;

testosterone decreases seen in men as they get older can be reversed with weight loss.

The problems with studies that follow obese patients to establish a link between their weight and their low testosterone levels is that it tracks patients once they are already obese, and already have low testosterone levels. This makes it difficult to clearly establish which health problem came first, or if they progressed together. It may be that they are both the indirect consequence of some other behaviour, such as dietary patterns or lifestyle and fitness levels.

Low Testosterone Promotes Obesity (and obesity related diseases)

Studies are increasingly finding that changing testosterone levels can be used to predict the development of metabolic syndrome and type 2 diabetes, when considered as a part of a wider picture of the patient’s health. One study noted that;

Epidemiological studies support a bidirectional relationship between serum testosterone and obesity as well as between testosterone and the metabolic syndrome.


This may be because testosterone has an impact on glucose, insulin, and fat regulation, and an imbalance or deficiency of testosterone can lead to imbalances in these areas, which inevitably lead to changes in weight and body composition in the long term.

Metabolic syndrome increases the risk for heart attacks and strokes, and is often a precursor to type 2 diabetes, and other serious health complaints. Furthermore, lower-than-normal testosterone levels increase accumulation of fat deposits, particularly abdominal (visceral) fat. This fat distribution is associated with higher chances of developing metabolic syndrome and therefore other serious health complaints, namely type 2 diabetes and cardiovascular disease. Metabolic syndrome is a condition that includes the presence of abnormal cholesterol levels, high blood pressure, waistline obesity, and high blood sugar.

Effects upon Muscle Mass

Muscled GuyDeclining testosterone levels mean that it is more difficult to maintain muscle mass. This may act as another factor contributing to weight gain. This is because muscle mass is a large factor in determining your metabolic rate, and any decline in metabolism, without adjusting calorific intake to accommodate these changes, can lead to weight gain. To counteract this effect of lowering testosterone levels, men should consider increasing the frequency that they exercise, and should consider adding strength training. Even small amounts of strength training performed regularly can make significant differences to the amount of muscle mass a person has, as well as to his resting metabolic rate.

Studies have also shown that exercise causes testosterone levels to rise, making it an invaluable tool for improving health in general. This advice translates to women as well, in terms of weight loss; more muscle means a higher metabolic rate, which can have a significant impact upon dieting efforts.

Can Testosterone Treatments Aid Weight Loss?

One recent study (Source) suggests that testosterone treatments over a prolonged period of time do have a positive, and significant impact upon weight and BMI as well as waist size. The participants, all overweight or obese men between the ages of 38 and 83, were studied over five years, and lost an average of 36lbs over the course of five years. Participants were given advice on how to improve their diets and lifestyle, but were not following a controlled diet or exercise regime.

The researchers noted that long term testosterone;

treatment reverses fat accumulation with significant improvement in lean body mass, insulin sensitivity and biochemical profiles of cardiovascular risk.


However, some scientists have speculated that the link between treating low testosterone levels and weight loss may be indirect. Treating low testosterone levels improves mood, energy levels, and reduces feelings of fatigue. These changes may make weight loss efforts less challenging, as poor mood and lack of motivation, as well as low energy levels are all known to derail diets, as well as reduce the chances of actually making it to the gym to exercise.

Comments have also been made about the motivations of the above-mentioned study, as it was partially funded by Bayer Pharma, a company that manufactures a brand of testosterone undecanoate, a form of injectable testosterone that was used in the study. The lead author was also an employee of the company.

Other studies that focus upon the consequences of testosterone treatments have found that muscle mass increases and fat mass decreases. However, total weight loss varies between studies, especially as they all follow patients for varying amounts of time.

Studies have also found that when patients lose weight their testosterone levels rise naturally.

Our Conclusion

Obviously low testosterone is not going to be the only factor in causing weight gain; it is more likely that lowered testosterone levels are contributing to weight gain, alongside other poor habits. Diet and exercise will always play the most significant role in determining body weight and composition, and may even help to boost testosterone levels as well.

It is also important not to self-medicate or self-diagnose. If you suspect low testosterone levels to be a factor in weight changes or mood changes, it is best to speak to a medical professional, who will be able to run tests to clearly establish the source of the problem.

Non-medical intervention is always preferable to long term medical treatment, and your doctor will be able to suggest numerous ways in which to naturally increase testosterone levels, as well as the best ways to safely and permanently lose weight

Disclaimer: Our reviews and investigations are based on extensive research from the information publicly available to us and consumers at the time of first publishing the post. Information is based on our personal opinion and whilst we endeavour to ensure information is up-to-date, manufacturers do from time to time change their products and future research may disagree with our findings. If you feel any of the information is inaccurate, please contact us and we will review the information provided.

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