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Does Intermittent Fasting Affect Testosterone Levels?

Isaac Robertson
Published by Isaac Robertson | Co-Founder & Chief Editor
Last updated: August 13, 2023

As a fitness instructor for nearly ten years, I've experimented with various fasting methods to maintain and increase my testosterone levels.

And today, I'd like to share it with you.

Intermittent fasting is widely regarded as having numerous health benefits. Studies have also found that energy restriction and hormones are closely linked.

So, keep reading because I'll go over in detail how intermittent fasting can help you deal with low T levels.

Quick Summary

  • Fasting affects testosterone levels by eliminating the excess estrogen, which automatically leads to the production of more testosterone hormones.
  • Testosterone levels rise during fasting because of the calorie restriction on different hormones.
  • Improved insulin levels, increased luteinizing hormone, and increased growth hormone are other benefits attributed to fasting.

What Is Intermittent Fasting?

grey plate and utensils

Intermittent fasting is a meal timing technique that alternates calorie restriction and regular eating periods over a set time.

Also known as intermittent energy restriction, its methods vary in intensity and in frequency which includes: 

  • The 5/2 fast consists of two days per week of restricted calorie intake ranging from 500-600 calories per day, with the remaining five days following a regular meal diet.
  • The 16/8 fast limits the amount of time you can eat in a day to eight hours. People on this plan usually fast between dinner and lunch the next day.
  • The 24-hour fast entails deciding on one or two days per week when no foods are consumed in the period between two dinners.

Studies indicate that this calorie and time-restricted eating practice is powerful in helping people drop body fat, decrease the risk of cancer, and improve cognitive abilities [1].

However, further investigation is required to support these findings.

person using a tape measure on his body

Hormone resistance and an unhealthy diet may negatively impact testosterone levels [2].

On the other hand, fasting helps balance your hormones and curb your appetite [3].

Evidence suggests that men experience a significant decrease in the male hormone testosterone after glucose intake [4].

So there's a big possibility that overeating before a blood test could lead to a false diagnosis of low testosterone levels or hypogonadism.

It may be beneficial to monitor your blood glucose levels to avoid eating before retesting your total testosterone levels.

Studies suggest that energy restriction affects hormones, including Leptin, Ghrelin, Adiponectin, and Growth hormone [5,6].

Also, it can improve insulin resistance and sensitivity and increase LH hormone health that may contribute significantly to improving low testosterone levels.

How Does Intermittent Fasting Affect Testosterone Production?

man holding up a plate and thinking

Intermittent fasting affects testosterone production by eliminating excess estrogen during autophagy.

The natural process of replacing old cells with new ones increases during energy restriction.

Since estrogen opposes testosterone, the more estrogen compounds you produce, the lower your testosterone gets [7].

Removing excess estrogen may allow the levels of testosterone to rise.

Why Does Testosterone Rise During Intermittent Fasting?

shirtless man showing off his arm muscles

Testosterone rises during intermittent fasting because of the positive effects of calorie restriction on various hormones like Insulin and LH that coordinate different systemic functions.

Fasting Improves Insulin Levels

Studies reveal that intermittent fasting can increase insulin sensitivity, thus decreasing insulin resistance [8]. Insulin is a vital hormone produced by the pancreas.

Calorie restriction improves insulin sensitivity which helps in glucose uptake and homeostasis.

When your circulating blood glucose is average, your body produces less insulin, giving your body more time to convert fat into energy, resulting in weight loss.

Also, calorie restriction helps adequate insulin production. Insulin has been shown to suppress the synthesis of sex hormone-binding globulin or SHBG [9].

SHBG binds and transports testosterone, thus controlling the amount of testosterone that your tissues can use.

This mechanism of testosterone insulin sensitivity to losing excess fats and decreasing SHBG synthesis gives an indirect approach to boosting testosterone levels.

Moreover, optimizing insulin sensitivity through fasting and calorie restriction may benefit overall health. Promoting insulin sensitivity supports testosterone regulation and contributes to a healthy metabolic profile.

It's important to note that while fasting and calorie restriction can offer potential benefits for insulin sensitivity, testosterone levels, and overall health, it's crucial to approach these dietary changes with care and moderation.

Consulting with a healthcare professional or a registered dietitian is advisable to ensure a balanced and suitable approach tailored to your needs.

Fasting Increases Luteinizing Hormone

ab view of a man with measuring tape

Fasting increases Luteinizing Hormone (LH), a testosterone precursor hormone that stimulates testicular function for practical testosterone synthesis.

In 1989, a short-term study found that intermittent fasting in men increases LH by up to 78 percent.

The study investigated the effect of starvation on the LH levels of nine obese men and eight non-obese men.

While no substantial effect was reported in obese men, fasting increased LH by 67 percent in non-obese men, increasing the overall testosterone boost by 180 percent [10].

This study supports the concept that fasting increases LH hormone health, required for a healthy average testosterone level.

Fasting Increases Growth Hormone

Intermittent fasting naturally increases growth hormones.

The human growth hormone (HGH) affects different physiological processes, including immune response, metabolism, and cell growth.

In one study, the increase in HGH after short-term fasting of two days was 400 percent on average.

Another showed that growth hormone increases after short periods of starvation.

Although some athletes inject HGH artificially, evidence suggests calorie restriction may be safe to increase this hormone.

HGH works like a gonadotropin, stimulating testosterone through pituitary-testicular functions resulting in testosterone secretions.

Fasting Regulates Leptin, Adiponectin, And Ghrelin Levels

old man with bowl of fruits

Intermittent fasting also affects the levels of other hormones that help you maintain energy levels and store fat.

Intermittent fasting helps regulate Leptin

Your adipocytes primarily produce the "satiety hormone" Leptin. It helps in the regulation of energy balance by signaling to your brain that you are full.

Research suggests that calorie restriction can help reduce excessive production of Leptin, thus improving its sensitivity [11].

Good levels of Leptin and sensitivity effectively regulate metabolic homeostasis by curbing your appetite, increasing energy expenditure, and fat oxidation resulting in weight loss and a rise in your testosterone.

Intermittent fasting helps regulate Ghrelin

Ghrelin is the "hunger hormone," which alerts your hypothalamus that you are hungry.

Evidence suggests that intermittent fasting elevates Ghrelin levels, which reduces appetite and food intake.

When you consume fewer calories than you burn, you can lose excess fats. Research suggests that having a leaner body composition also contributes to the increased levels of testosterone [12].

Intermittent fasting helps regulate Adiponectin. 

Adiponectin is another adipose-derived hormone that influences various metabolic processes such as glucose regulation and fatty acid oxidation, which help treat obesity.

Also, when you increase Adiponectin, it results in an increased insulin sensitivity [13] which serves as an indirect avenue that raises significant levels of testosterone [14].

Fasting Helps Lose Body Fat

man showing his belly fat

Research points out that the more body fat you have, the less testosterone your body can produce.

Calorie and time-restricted eating can help you gradually drop body fat and create a positive cycle for T production.

According to a 2014 study, calorie restriction could cause an 8 percent weight loss over 24 weeks [15].

For a year, intermittent fasting should allow you to lose 14 percent of your fats.

"There's no denying that anytime you cut calories from your diet, you're going to see the scale drop."

- Despina Hyde Gandhi, RD, CDE, Dietician at NYU Langone's Weight Management Program & President of the Greater NY Dietetic Association

Testosterone is strongly linked to body fat through shared genes. According to research, testosterone has a 23 percent genetic correlation with body fat. That's why a decrease in body fat may lower the T levels [16].

What Are The Benefits Of Intermittent Fasting?

shirtless man giving a thumbs up

According to research, intermittent fasting benefits overall health because it offers several health benefits [17].

Calorie restriction may aid in blood sugar control and may lessen the risk of Type 2 diabetes.

Furthermore, a study found that people with diabetes who fasted did not require additional insulin level treatments.

It has also been shown to benefit heart health by lowering blood pressure and increasing good cholesterol levels.

Caloric restriction may potentially lower the risk of cancer by reducing oxidative stress and slowing cell aging.

It also improves mental health in healthy men by alleviating fatigue and low sex drive, optimizing cognitive function, and increasing the brain's resistance to injury and disease.

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Does Intermittent Fasting Increases Testosterone Levels: The Verdict

Yes, increased testosterone health influences body fat levels through proper hormone regulation and weight management.

In intermittent fasting, you restrict calorie intake, increase energy balance, and lose body fats, along with its ample health benefits.

By removing excess fat and losing some extra pounds, your body increases testosterone synthesis.

However, before embarking on a calorie and time-restricted feeding plan, it is best to consult a professional doctor to assess your medical condition.

By combining it with a consistent workout and a healthy nutrition plan, you'll be well on your way to having healthy testosterone levels that will improve the overall quality of your life.


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