Intermittent fasting is notable for its exceptional weight loss potential and, as of late, its physical and psychological health benefits. Although research in this area is relatively new and somewhat tenuous, much interest currently lies in establishing a causal link between intermittent fasting and testosterone levels.

Understanding intermittent fasting

Intermittent fasting has spiked in popularity in recent years—enticing many practitioners who prefer to restrict when they can eat rather than what they can eat. Intermittent fasting consists of periodic fasting (from several hours to a few days) with periods of regularly scheduled eating in between to produce a caloric deficit. The idea of suspending eating for a time can seem intimidating to newcomers, but there are plenty of options to choose from depending on your schedule, weight-loss goals, or comfort level:

Time-restricted eating

You already spend much of your time fasting—while you sleep. This strategy involves setting a regular eating window (9 am to 5 pm, for instance), and extending your overnight fast to 14-16 hours. With this strategy, you don’t miss any meals, but it restricts you to a consistent daily routine in return—no movie night snacks or late nights at the pub. 

Twice-a-week (5:2) method

Sticking to a consistent fasting regimen can be challenging to maintain long-term. With the 5:2 strategy, you eat normally for five days, then fast consecutively for two. In theory, anticipating an upcoming large eating window makes it easier to weather your fasting days.    

Alternate day fasting

Not for the faint of heart, this variant involves alternating between 24-hour fasting and normal feeding days. Most practitioners proclaim that they never feel truly satisfied while on this diet (even on feeding days), making it challenging to continue long-term.

Eat-stop-eat (the 24-hour fast)

With this strategy, you fast for 24 hours once or twice a week, then return to your regular everyday routine. If you maintain the same eating habits during the feeding period, you should cap off the week with a calorie deficit. 

Whatever method you choose, intermittent fasting aims to help you lose weight by restricting calorie intake, reducing cravings, improving blood glucose uptake, and enhancing fat metabolism while minimizing muscle loss. 

But that’s not all. Intermittent fasting also provides a host of beneficial secondary effects, such as its potential to improve hormone profiles—including testosterone. 

Intermittent fasting and testosterone

Classic solutions such as maintaining a healthy diet and exercise routine can do wonders for your testosterone levels. However, consider adding intermittent fasting to your routine if your T levels still need a little boost. Although the relationship between intermittent fasting and testosterone levels is still unclear, some evidence suggests that fasting in short bursts may stimulate testosterone production and release. 

However, keep in mind that long fasts may reduce your testosterone levels, so limit your fast to a maximum of two days. 

Why does this happen?

It’s well-known that testosterone levels are positively correlated with muscle mass and negatively correlated with body fat accumulation. The more muscle you have and the lower your body fat composition—the higher your testosterone production. 

Intermittent fasting has not been shown to improve and maintain healthy testosterone levels directly. However, this diet affects many body systems and hormones in fat loss and muscle gain, suggesting that it can enhance your T levels—albeit indirectly.  

Impact on insulin levels:

Body fat directly impacts testosterone levels—the less fat you have, the more testosterone your body produces. Insulin, a hormone your pancreas produces, regulates blood glucose levels by promoting glucose uptake in your cells. Intermittent fasting reduces your insulin levels, which makes your fat reserves more accessible for consumption, thus slimming your waistline and increasing your T levels. 

Intermittent fasting also increases insulin sensitivity, reducing your risk of developing type 2 diabetes and reducing the need for insulin treatment in people with diabetes. 

Impact on human growth hormone (HGH):

Muscle mass is correlated with testosterone levels—the more muscle you have, the more testosterone your body produces. HGH is responsible for many body functions, including cell growth and repair—promoting muscle recovery and growth following an intense workout. Intermittent fasting increases HGH levels by almost 500%, which can help you put on muscle faster, thus increasing your body’s long-term testosterone levels. 

The more muscle mass you put on, the more calories you burn—promoting fat deposit reduction and a slimmer waistline—contributing to increased testosterone production.

Impact on luteinizing hormone (LH):

LH, a hormone produced by the pituitary gland, stimulates the testes to produce sperm and make testosterone. Intermittent fasting improves LH levels, which directly enhances testosterone levels. Women also have LH, but LH only raises testosterone levels in men. For women, LH controls menstruation, egg release, and estrogen production instead.

Other hormones impacted by intermittent fasting 


Leptin, the satiety hormone, makes you feel full and less interested in food. It’s secreted by your stomach and fat cells, signaling to your brain that eating isn’t required because there are fat stores to use instead. Unfortunately, high body fat can result in leptin resistance, making you more susceptible to cravings and hunger pangs. However, intermittent fasting improves leptin sensitivity, suppressing your desire for food, making it easier to lose weight, and thus increasing your testosterone levels. 


Adiponectin, a hormone secreted by fat cells, is responsible for many metabolic and anti-inflammatory effects, most notably increasing insulin sensitivity in the muscles and release by the pancreas. This improves glucose uptake by your cells, reducing sugar cravings, helping you lose weight, and thus increasing your T levels. 


Ghrelin, the “hunger hormone,” is secreted by your stomach lining—making you feel hungry and increasing your appetite. The higher your ghrelin levels, the hungrier you get. The lower your levels, the fuller your feel and the easier it becomes to avoid overeating. Ghrelin tends to be overexpressed in overweight individuals, leading to uncontrollable feeding behaviors. Intermittent fasting, however, has been shown to reduce ghrelin levels during fasting periods, suppressing appetite and making it easier to stick to your diet and lose weight. Thus, intermittent fasting may indirectly support healthy testosterone levels by making it easier to maintain a healthy body fat composition.

The benefits of intermittent fasting

Intermittent fasting is mainly used as a fast-acting weight loss method by restricting calorie intake and moderating hormones involved in hunger regulation and energy absorption. However, it provides a host of other physical and psychological benefits, including:

Improving muscle mass retention

With many calorie-restricted diets, your body may consume your muscle for energy alongside your unwanted body fat. Intermittent fasting, however, boosts your HGH levels, inhibiting muscle breakdown and improving muscle growth (when combined with an active lifestyle).

Lowering heart disease risk

Improves blood pressure, heart rate, and blood sugar levels.

Lowering risk for type 2 diabetes

Intermittent fasting lowers your insulin resistance and blood insulin levels—improving your body’s ability to moderate and lower your blood sugar. 

Lowering inflammation

Intermittent fasting’s anti-inflammatory effects may help improve the condition of many inflammation-associated conditions such as arthritis, asthma, multiple sclerosis, stroke, and Alzheimer’s disease.

Reducing oxidative stress

Unstable molecules called free radicals can damage your proteins and DNA, potentially increasing your risk of certain types of cancer. Intermittent fasting may improve your cellular response to oxidative stress caused by free radicals.

Improving cellular repair

In a fasted state, your cells digest and remove redundant, dysfunctional proteins that accumulate in your cells, helping improve cellular and tissue function. 

Improving cognitive performance

Intermittent fasting has been shown to help boost memory and concentration.


Intermittent fasting is an excellent option for those looking to slim their waistline, improve their health, and boost their testosterone levels. However, much of intermittent fasting’s testosterone-boosting potential is because it helps you lose weight—making it no less or better than any other diet in terms of raising testosterone. If you already have a healthy body weight, you may want to look elsewhere for your testosterone-boosting needs.

However, this doesn’t mean intermittent fasting isn’t worth your time. If you are overweight and are looking to supercharge your weight-loss efforts, regulate some key hormones, and improve your overall health profile, intermittent fasting may be the diet for you. 

About the Author Tim Rockwell

Tim Rockwell is a highly skilled and knowledgeable fitness expert. With a background in exercise science and years of experience in the fitness industry, Tim is passionate about sharing his expertise with others through his writing. He currently contributes articles to Eurasc, where he shares practical tips and strategies for leading a healthy, active lifestyle.

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