Does Fasting Increase Testosterone?

Fasting is widely known for its positive effects on the body and its potential to enhance overall health. So, how exactly does fasting affect hormones, specifically testosterone—a key hormone for muscle growth, energy production, and reproductive health? 

Continue reading to learn whether or not fasting increases testosterone levels and what science has to say about it.

Understanding Testosterone: What Is It and Why Is It Important?

Testosterone is an essential hormone for men and women alike. It is the primary male sex hormone that regulates sex differentiation, producing male sex characteristics, spermatogenesis, and fertility. Besides promoting the development of male growth and masculine characteristics, testosterone plays many important roles in the body, such as: 

• promoting muscle size and strength

• supporting bone growth and strength

• enhancing sex drive (libido)

• regulating energy levels and mood

Various factors influence testosterone levels, including age, diet, exercise, stress, underlying medical conditions, and overall lifestyle. 

What Is Fasting?

Fasting involves periods of abstaining from food, ranging from just a few hours to several days. During fasting periods, you can drink calorie-free beverages, such as water, plain-black coffee, or unsweetened tea. Fasting has been present for centuries for both religious and cultural reasons. A popular fasting approach practiced for its spiritual benefits is dry fasting, which requires abstaining from eating or drinking for the entirety of the fast. 

Types of fasting 

Through time, variations of fasting have emerged, allowing individuals to choose the approach that best fits their lifestyle and health goals. 

• Intermittent fasting, also known as time-restricted eating (TRE), only allows individuals to eat during specific eating windows. Some variations include 16:8 (the most popular), 14:10, and 20:4. 

• Alternate-day fasting (ADF) entails alternating between normal eating days and days of significantly reduced calorie intake (around 500 calories or less) or complete fasting.

• Extended fasting requires individuals to fast for more than 24 hours or more. Prolonged fasting entails not eating or drinking anything—unless it’s a water-only fast.

Discover the fast that best adapts to your goals, routine, and commitment level by taking the Fastic quiz. Answer simple questions about your everyday routine and health objectives to get your unique fasting protocol.

Potential Benefits of Fasting 

The potential benefits fasting can offer are the following:

• weight management

• help prevent heart disease

• lower risk of chronic diseases

• promote cellular renewal

• reduce inflammation

• improve insulin sensitivity

• enhance cognitive function

• lower cholesterol levels and blood pressure

Does Fasting Increase Testosterone?

Studies have demonstrated that, while fasting can help regulate hormone levels, it can also hurt them. Various fasting studies have reported a decrease in testosterone levels, particularly when combined with high-stress or prolonged fasting periods. However, it has not been conclusively determined that fasting cannot also increase testosterone levels. 

Here is what scientific research has found so far:

• Research has shown that higher body fat is linked to lower testosterone levels, suggesting that fasting’s potential for weight loss could positively impact testosterone levels in obese men.  

• A study on physically active, young men found that intermittent fasting reduced testosterone levels in lean men, but did not affect sex hormone-binding globulin (SHBG) concentrations. A lack of change in SHBG levels is positive—high SHBG levels can reduce the bioactivity of testosterone. When SHBG is high, even if testosterone levels are increased, its effects on muscle growth, libido, and other areas may be diminished. It also noted that muscle mass and muscular strength were not negatively impacted.

• Fasting can induce stress, which can negatively affect testosterone production. A study on the link between stress and testosterone levels found that besides stress itself, specific genes related to the body’s stress response can influence cortisol levels, and changes in cortisol levels can impact testosterone levels. 

• Another study on reproductive function during fasting in men found that testosterone concentration was significantly reduced after intermittent fasting for nine days.

• After a 12-month time-restricted eating study, participants’ body mass, insulin-like growth factor 1, and testosterone were significantly lower compared to those following a normal diet protocol. 

The key takeaway from these studies is that while fasting can reduce testosterone levels in normal-weight men, it may support long-term testosterone production in overweight men.

The Impact of Fasting on Other Hormones

As mentioned, fasting impacts hormones both positively and negatively. While research hasn’t confirmed that fasting increases testosterone, evidence suggests it can positively influence other hormones.

• Human Growth Hormone (HGH): This hormone is responsible for maintaining normal body structure and metabolism, including regulating healthy blood sugar levels. A study on the effects of short-term fasting on HGH secretion found that HGH secretion increased five-fold after two days of fasting.

• Insulin: Insulin is a hormone produced in the pancreas. It helps regulate blood sugar levels and allows you to store and use sugar from the foods you eat. A study on the effects of an intermittent fasting diet on insulin resistance found that intermittent fasting has a therapeutic effect on blood glucose and lipids in patients with metabolic syndrome and significantly improves insulin resistance.

• Leptin and Ghrelin: Leptin is the satiety hormone that informs your body when it’s full. Research shows that leptin levels typically decline during fasting, which may contribute to an increase in appetite. Ghrelin, on the other hand, is the hunger hormone that signals when you are hungry. Studies have found that fasting can lead to an increase in ghrelin, which may heighten the urge to eat.

Best Intermittent Fasting Protocol for Men

There is no best intermittent fasting protocol for men. Various factors will determine the best fasting approach for your health, lifestyle, and objectives. Certain fasting methods may be more effective than others depending on how your body responds and changes over time. To discover the best intermittent fasting protocol for your age, check out this article on intermittent fasting for men over 40.

Tips for Safe Fasting to Support Proper Testosterone Levels

Follow these recommendations to ensure your body is in optimal shape during your fasting experience.

• Nutrient-dense diet: A shorter eating window means less time to eat and provide your body with the essential nutrients it needs. Focus on following a balanced diet with optimal amounts of protein, carbohydrates, and fats. 

• Proper calorie intake: Intermittent fasting may lead to inadequate food intake. Make sure you consume enough calories to meet your daily calorie intake, particularly during eating windows. 

• Hydration and electrolytes: Shorter eating windows may lead to insufficient nutrient and water intake from food. Stay hydrated and drink electrolyte-rich beverages to support bodily functions.

• Exercising and strength training: Exercise in a fasting state decreases body weight, free fat mass, and fat mass. Combine fasting with exercise and strength training to maximize weight loss while preserving muscle.

• Proper sleep and stress management: Prioritize quality sleep and help your body manage stress to support hormone balance. Engage in stress-relieving techniques such as meditation, yoga, or jogging. 

Research on the impact of fasting on testosterone still has a long way to go. Although fasting has shown mixed effects on testosterone levels, it is clear that it can positively influence other hormones and offer numerous benefits that support overall health. Download the Fastic app to get personalized fasting guidance, tips on hormone-friendly nutrition, and lifestyle practices to help you enjoy a safe, hormone-supportive fasting experience. 

Disclaimer: It is advised to speak with a health professional before beginning intermittent fasting or a diet program. There may be side effects for people with certain medical conditions.