When it comes to hormones, testosterone, thyroid, and insulin get most of the attention. Yet growth hormone, also known as somatotropin, also plays an essential role in your long-term health, athletic performance, and longevity.



It affects the health of your body as well as your brain.



I’ll explain what growth hormone is, how it affects your health, and then what you can do to sabotage and support it.





What is growth hormone?



Growth hormone (GH), as its name suggests, influences tissue growth and repair throughout life. Its primary role is in cell regeneration.



Your anterior pituitary gland secretes growth hormone in response to low blood sugar, hunger, exercise, and deep sleep.



This is important to understand because most people's lifestyle choices conflict with those four circumstances.



Growth hormone:




regulates fat, carbohydrate, and protein metabolism



controls body composition



affects skin health



enhances bone density



helps build and maintain muscle mass



enhances recovery from exercise and injury. 



may protect against age-related cognitive decline




It stimulates the growth of newborns and teenagers. It helps you build muscle, bone, and connective tissue. When levels fall, muscle mass, and overall health deteriorate.



Growth hormone and metabolism



Thyroid hormone is the primary metabolic rate regulator, but GH influences metabolism as well.



Growth hormone enhances cardiac output, which increases blood flow to muscle tissue and specific organs.



Studies show GH can increase metabolic rate by 10-20%!



Growth hormone not only increases the number of calories you burn, but it also alters the type of calories you use for energy. As a “nutrient partitioner,” it shifts your body from burning carbohydrates and amino acids and storing fat, to burning fat and storing carbohydrates and amino acids.



It helps to build or rebuild muscle, bone, skin, and organ tissues. However, when energy intake is low or when you fast, GH levels rise to conserve amino acids, sparing muscle and causing your body to burn fat for energy.



Symptoms of Low Growth HormoneIncreased body fatIncreased waist-to-hip ratioIncreased belly (visceral) fatMuscle lossDecreased bone densityDecreased strengthReduced exercise performanceReduced VO2 MaxDecreased max heart rateReduced resilience to stressDecreased physical and mental energyLack of motivationLack of libidoIncreased need for sleepCardiovascular problemsElevated blood pressure



Many of these symptoms have similarities with imbalances of other hormones.



For example, low thyroid, low testosterone, elevated estrogen, or excess cortisol contribute to increased body fat, reduced libido, and decreased mental and physical energy. Decreased VO2 Max is also typical in hypothyroidism. And cardiovascular problems occur with low thyroid, low testosterone, and elevated cortisol.



The point is, if you see yourself in some of the symptoms above, it doesn’t guarantee you have low GH. But it does suggest you should order a full hormone panel through your doctor.



What causes low growth hormone?



Genetic factors cause low growth hormone in a small percentage of the population, which may cause small stature. For most people, though, low levels are a self-inflicted situation.



The following are the most common contributors.



Obesity or excess belly fat: Excess fat, especially belly fat, blunts GH secretion. As body fat levels rise, levels decrease, which suppresses fat metabolism even further, making it more likely you'll gain more body fat.



How much of an effect does obesity have on growth hormone? Research shows that for each point someone’s BMI increases, growth hormone drops by 6%.



Sleep debt: Growth hormone secretion peaks during deep sleep. If you go to sleep at inconsistent times, leave lights on at night, drink too much alcohol, eat too close to dinner, or sleep in a bedroom that's too hot, you'll compromise deep sleep,