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Growth hormone, or somatotropin, is a hormone needed for proper growth and development. While it has many health benefits, an excess amount of this hormone can cause health problems as well. Read below to learn about its pros and cons.
What Is Growth Hormone?
Growth hormone (GH), also known as somatotropin, is a peptide hormone that stimulates growth, increases muscle mass, reduces fat mass, and helps maintain normal blood glucose levels .
GH is synthesized and secreted by a brain region called the anterior pituitary gland. Its secretion is primarily controlled by two hormones: GH-releasing hormone (GHRH) and somatostatin. GHRH stimulates the release of GH into the bloodstream, while somatostatin inhibits it .
GH is secreted episodically. Because it has multiple important functions other than promoting growth, this hormone is secreted during all stages of life. GH secretion :
- Is low during childhood but increases slightly until puberty
- Is greatly increased during puberty until it decreases in late adolescence
- Remains stable until approximately 30 years old in age
- Progressively declines from 30 years old on
Role of Growth Hormone in Growth
GH acts both directly and by stimulating IGF-1 .
When released, GH travels from the anterior pituitary gland to the liver and cartilages via the bloodstream and binds to its receptor, growth hormone receptor (GHR), which triggers the production of insulin-like factor 1 (IGF-1). Both GH and IGF-1 are needed to simulate normal growth [1, 3].
GH acts at the growth plate and increases growth by promoting cell differentiation and expansion. It increases bone mass by stimulating bone cell proliferation [1, 4].
It also increases the transport of amino acids into muscles to promote muscle fiber growth and distribution .
In fat tissues, GH increases the breakdown and mobilization of fats [1, 5].
1) May Increase Muscle Mass and Strength
In a clinical trial on 13 healthy men aged 50-70, GH stimulated collagen synthesis in the tendons and muscles, resulting in an increased strength .
In another trial on 16 healthy people over 60 years old, GH sped up protein synthesis in the muscles and increased muscle mass and strength .
For this reason, athletes and bodybuilders commonly use GH as a performance-enhancing drug .
Conversely, people with GH deficiency typically show reduced muscle mass and strength compared to those with normal levels .
Acromegaly is a condition caused by an excess of GH. People with acromegaly have large muscles, but their mass doesn’t match their strength due to an uneven composition of the muscles that hinders power output .
2) May Increase Bone Mass
GH plays a key role in bone growth in length and mass during childhood. GH deficiency has been associated with reduced bone mineral density, resulting in an increased risk of bone fractures [10, 11].
Therapy with GH can improve bone mineral density and reduce the risk of osteoporosis and fractures in people with a deficiency in this hormone [11, 12, 13].
3) May Increase Metabolism
GH increases the basal metabolic rate (BMR), which is the amount of energy consumed while at rest. In a small trial on 7 people, GH deficiency was accompanied by low BMR that could be corrected by supplying the hormone. GH also reduced body fat and increased fat-free mass .
4) May Reduce Body Fat
GH supplementation increased fat breakdown in a clinical trial on 24 obese people .
Both children and adults with GH deficiency have increased fat buildup, especially in the belly. GH supplementation helps burn this fat and redistribute it throughout the body .
5) May Lower Blood Fat Levels
In a study in mice, GH lowered blood triglyceride and cholesterol levels .
In a study on 31 people with a genetic condition that causes “bad” LDL cholesterol to be very high (familial hypercholesterolemia), GH supplementation slightly lowered LDL levels .
6) May Help Fertility
GH is involved in the regulation of fertility and has been used in treatments to manage infertility in both genders, especially in women .
In addition to the pituitary gland, the ovaries also produce GH. Together with IGF-1 and GHRH, it increases the sensitivity of the ovaries to gonadotropin stimulation and enhances follicular development .
GH helps in follicular growth and its supplementation is one of the treatments used for ovarian stimulation in assisted reproductive technologies. GH has been shown to improve pregnancy rates in selected cases .
GH also enhances aromatase and 3-β-hydrogenase activity, thus increasing the conversion of androgen into estrogens in females. This effect occurs through a direct and IGF-I-mediated mechanism. GH, IGF-1, and IGF-2 all affect the maturation of the follicle and egg as well .
7) May Improve Wound Healing
Supplementation with GH increased the rate of tissue regeneration and wound healing in a clinical trial on 46 children with large burns .
GH also showed beneficial effects in people with severe wounds, traumatic injuries, and bone fractures [22, 23].
8) May Promote Heart Performance
GH increased the performance of the left ventricle in rats, thus increasing the force with which blood is pumped throughout the body and reducing the risk of heart failure. This hormone also decreased blood vessel resistance, thus increasing blood flow and oxygen supply .
9) May Regulate the Immune System
GH has multiple effects on the immune system. It causes the proliferation of white blood cells and regulates antibody production by B cells, thymulin secretion by the thymus, and natural killer, engulfment (phagocytosis), and oxidative burst capacity of white blood cells (neutrophils and macrophages) [25, 26].
However, GH deficiency doesn’t seem to affect the immune system drastically. In humans, it’s not associated with immunodeficiency and only minor abnormalities in immune functions have been reported .
The hypersecretion of GH (mostly due to benign tumors in the pituitary gland) results in a condition called acromegaly. Acromegaly is characterized by skeletal deformities (such as jaw overgrowth, skull expansion, and eyebrow bulging), soft tissue swelling (resulting in enlargement of the hands, feet, nose, lips, ears, and some organs), and thick, rough, oily skin [28, 29].
Acromegalic patients also suffer from severe headaches .
Similarly, a study on almost 58,000 on GH therapy found headaches and dizziness as adverse effects sometimes experienced during the treatment .
3) Vision Disturbances
Blurred vision or complete blindness are occasional symptoms of acromegaly. The increased thickness of the retina may be responsible for these effects [32, 33].
GH secretion increases when the blood glucose level is low (hypoglycemia). Its effects counteract those of insulin, leading to high blood sugar levels and insulin resistance .
Under pathological conditions of GH excess, it can cause increased glucose production, decreased muscle glucose uptake, and rising blood glucose levels, thus increasing the risk of type 2 diabetes .
In a small clinical trial on 8 people treated with GH for short bowel syndrome, swelling of the lower limbs occurred in all patients during the treatment .
6) Muscle and Joint Pain
Joint hypermobility syndrome is a genetic disorder that affects the joints and causes pain and exhaustion. In a study on 31 people with this condition and matched controls, joint and muscle pain was associated with high blood GH levels .
7) Sleep Apnea
Two studies on over 200 children receiving GH therapy found that, although rarely, sleep apnea could occur as a side effect of the therapy [38, 39].
GH has been suggested to have the potential to induce cancer due to its ability to stimulate cell proliferation. Anecdotally, a man and his wife developed skin cancer while using topical GH as an anti-aging supplement .
So far, however, no studies have found a direct relationship between GH and cancer .
Factors that Can Increase Growth Hormone Levels
The most important thing is to work with your doctor to determine what underlying condition is causing your low GH levels and establish if you need GH therapy. The additional strategies below are other measures that you may try as an add-on to your treatment regime if you and your doctor determine that they could be appropriate.
Exercising is a very potent stimulator of GH secretion. Both aerobic and resistance exercise results in a significant increase in GH secretion, being its level correlated with exercise intensity [42, 43].
Given its multiple health benefits, it’s always a good idea to do more exercise. Although it may be less effective at promoting GH secretion, moderate exercise is more beneficial to overall health.
GH secretion increases during sleep, especially during the slow-wave stage .
Getting a good night’s sleep is always a good idea if you want to achieve optimal health. Avoid sleep deprivation and be cautious of anyone selling you the idea that you can sleep for less than 6 hours and still be healthy.
You can improve your sleep by trying these methods and optimize it by improving your circadian rhythm.
3) Not Eating Immediately Before Bedtime
GH secretion increases during sleep. However, if food is consumed immediately before bedtime, the rise in blood glucose levels will lead to an insulin spike that will block GH secretion [44, 45, 46].
Eating dinner some hours before going to bed may help you prevent this effect.
In a clinical trial on 55 healthy volunteers, blood GH levels increased by 142% after a sauna. However, these levels had returned back to normal after 1 hour .
5) Reducing Stress
In a cell-based study, the stress hormone cortisol inhibited GH secretion .
Because stress has many negative effects on overall health, it’s always a good idea to reduce it. You can avoid stressful triggers as much as possible and change what your body perceives as stress by deep-breathing exercises and meditation.
The following dietary interventions may also help raise your blood GH levels. Remember to talk to your doctor and never follow a strict diet without supervision.
1) Reducing Sugar Intake
Sugar intake causes a well-known rise in insulin levels. Because this hormone inhibits GH secretion, lowering sugar intake can help raise GH levels [45, 46].
Fasting stimulates GH secretion, as seen in a small study on 6 men. Remember to talk to your doctor before implementing fasting and carefully follow their recommendations to prevent malnourishment and other potential adverse effects .
The following supplements have been shown to stimulate GH secretion in clinical trials:
- Vitamin A 
- Arginine and ornithine [51, 52]
- Melatonin 
- Glycine 
- Supplements that promote ghrelin secretion 
- Acetylcholine 
- Thyroid hormones (T3) 
Remember that these supplements are not approved by the FDA to increase GH levels. Supplements generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
Ways to Decrease GH
As in the previous case, the most important thing is to work with your doctor to determine the cause of your high GH levels. Your doctor may prescribe surgery/radiation therapy to remove pituitary tumors or drugs that block GH release (such as somatostatin).
Below, we will discuss some diets that may help you lower your blood GH levels when used as an add-on to your treatment regime. Remember to discuss it with your doctor before implementing any drastic changes in your diet. Carefully follow your doctor’s recommendations to avoid nutrient deficiencies and any adverse effects associated with unsupervised diets.
1) High-Carb Diet
Sugar intake increases blood glucose level, which in turn promotes insulin secretion. By blocking GH production, high blood insulin may help lower blood GH levels [45, 46].
2) High-Fat Diet
Diets rich in fat cause blood fatty acid levels to rise, which leads to lower GH secretion .