Ibutamoren is a common topic of discussion in online forums relating to growth hormones and other muscle-building supplements. The hormone, also known as ibutamoren nubotrol or MK-677, is responsible for promoting the secretion of human growth hormone (HGH), as well as playing a role in increasing insulin-like growth factor (IGF-1).
Ibutamoren (MK-677) is a selective agonist of the ghrelin receptor, as well as a growth hormone secretagogue, which is commonly used as a diagnostic agent for determining growth hormone deficiency in patients. Most growth hormone secretagogues are used under strict medical supervision to treat conditions that lead to severe muscle wasting, including lipodystrophy induced by HIV. MK-677 is frequently mislabeled as a selective androgen receptor modulator (SARM).
The mechanism by which ibutamoren increases growth hormone levels involves imitating the actions of the ghrelin hormone, subsequently binding to one of the brain’s ghrelin hormone secretion receptors (GHSR) in the brain. So far, clinical studies have largely been focused on the effects of ibutamoren on appetite; much like ghrelin, ibutamoren has the effect of increasing one’s appetite. Ghrelin is a neuropeptide in the central nervous system produced in the human stomach which results in increased hunger; as such, those who take ibutamoren MK-677 experience a similar rise in appetite.
When the GHSR is activated in your brain, growth hormone is released due to stimulation of the pituitary gland. GHSR is typically located in the regions of the brain that control mood, appetite, memory, cognition, pleasure and your natural biological rhythms. As a result, it can be assumed that ibutamoren affects these functions as well.
One of the reasons ibutamoren has been so sought after is its tendency to increase growth hormone levels without increasing other hormones in the body, like cortisol. When cortisol levels increase in the human body, one experiences side effects like improper wound healing, suppression of one’s immune system, and impaired memory and learning faculties. Generally, it is not recommended engaging in treatments that increase one’s cortisol levels, which leads many to an increased interest in ibutamoren.
How do growth hormone levels relate to age?
As with most hormones, the human body produces growth hormone most frequently during childhood, spiking during puberty. However, as we get older (in our thirties and forties), our growth hormone levels level off and start slowly decreasing. The older we get, the less growth hormone our bodies naturally produce, which then leads to many of the effects we typically associate with old age.
What Happens When You Have Low Levels of Growth Hormone?
As humans get older, they are more likely to suffer from adult-onset growth hormone deficiency (AGHD) – a condition that is often characterized by lower muscle mass, higher fat mass, and other symptoms resulting from an overall lack of growth hormone in their systems. Sufferers of AGHD tend to have maladjusted lipid levels, which makes their triglyceride levels far higher.
AGHD can be caused by several different factors:
- Severe head injuries. There have been patients who have experience head trauma so intense as to cause permanent pituitary damage, leading to lower production of HGH.
- Childhood growth hormone deficiency. GHD also occurs in childhood, which can often result in conditions such as pituitary dwarfism. As such, these individuals will carry that condition with them all the way to adulthood.
- Pituitary tumors. The pituitary gland’s normal function can also be impaired by the presence of tumors, affecting the gland’s ability to produce HGH.
- Hypothalamic-pituitary disease. This disorder, particular to the hypothalamus and pituitary gland, also leads to diminished HGH production.
- Aging. Independent of acute drops in growth hormone production, the natural aging process can lead to larger deficits in growth hormone than others, leading to more pronounced effects.
Effects of Ibutamoren Therapy
Taking ibutamoren can have a number of desired effects on the human body. They include:
Higher muscle mass
People typically take ibutamoren as an anabolic substance with the goal of increasing one’s lean body mass. As ibutamoren increases growth hormone levels and IGF-1 alike, these have the effect of reducing body fat, as well as increasing muscle mass and overall strength. One study of twenty-four obese men found that ibutamoren treatments led to higher metabolisms and higher muscle mass.
Reversing muscle wasting
In addition to building previously missing muscle, ibutamoren has also been found to help reverse diet-induced protein loss that can lead to muscle wasting. Studies have also shown that elderly patients who take ibutamoren have seen marked increases in muscle strength, fewer falls and faster walking speed.
Better bone density
GH has been known to increase bone density and turnover; however, subjects treated with growth hormone tend to have increased bone turnover, and so it typically takes about a year of ibutamoren treatments for people to see increased bone density.
There have been several studies on this particular effect of ibutamoren; one study saw ibutamoren increase bone turnover in healthy obese men, while another saw increased bone osteocalcin in elderly adults. Another study showed ibutamoren increasing bone mineral density in post-menopausal women, a cohort especially prone to osteoporosis.
More restful sleep
Ibutamoren has been shown to help subjects get deeper, more restful sleep. One study demonstrated ibutamoren’s ability to improve sleep quality and duration of rapid eye movement (REM) sleep in both young and old subjects.
As previously mentioned, GH levels decrease with age; ibutamoren treatments have been known to help stave off the effects of aging, including GH and IGF-1 levels. IGF-1 is thought to have beneficial impact on human longevity, making ibutamoren’s ability to encourage production of that hormone particularly valuable. One study saw daily ibutamoren treatments increasing GH and IGF-1 levels without serious side effects. Another study involving twenty-four obese males saw ibutamoren completely rejuvenating their growth hormone profiles.
There are many people who use ibutamoren as a nootropic (i.e. a supplement intended to improve cognitive function). Ibutamoren acts on the ghrelin receptor, which elicits nootropic effects in the nervous system. While significant research is still pending on the link between ibutamoren and cognitive performance, the hormone contains some theoretical and anecdotal links to higher cognition.
Ibutamoren is thought to improve brain function due to a pair of indirect mechanisms. First, there is the hormone’s stimulation of IGF-1 levels, which improves learning and memory. Furthermore, ibutamoren increases REM sleep direction, and leads to better sleep quality; sleep is fundamental for solid cognitive function.
One study investigated the possibility for ibutamoren to aid in the low IGF-1 levels associated with Alzheimer’s disease; however, it was proven somewhat ineffective. However, future research could provide further insight into the hormone’s ability to improve human cognition.
Growth hormone deficiency
Ibutamoren has been shown to increase levels of growth hormone, IGF-1 and IGFBP-3 levels in children who have growth hormone deficiency. Most beneficially, ibutamoren does this without increasing levels of glucose, cortisol, insulin, or other hormones that should not be unduly altered in a child’s physiology. One study of GH-deficient adult men also found that ibutamoren increased growth hormone and IGF-1 levels with no thyroid and cortisol hormone levels; however, there was an increase in glucose and insulin levels.
Faster healing and tissue regeneration
With higher growth hormone levels come greater rates of tissue regeneration, and one’s wounds heal faster – ibutamoren can facilitate this regeneration at faster rates.
Okay, this one is mostly anecdotal, but there are reports of using ibutamoren to cure hangovers as well.
What are the Side Effects of Ibutamoren?
While the side effects of ibutamoren are extremely minor, they do exist. Most frequently, people report experiencing more ravenous appetites and the occasional bout of mild muscle pain in their lower extremities. Other studies report higher rates of fasting blood glucose and lower insulin sensitivity in patients. These are commensurate with side effects reported in people with higher growth hormone levels, like insulin resistance and joint pain.
If you have a heart condition and a history of prior heart failure, it might be prudent to consult your doctor before taking ibutamoren. One study in elderly patients with hip fracture, ibutamoren increased their blood pressure and blood glucose levels, leading to some case of congestive heart failure.
Some recent research has also raised concerns about ibutamoren’s longer half-life, which has the potential to over-stimulate the ghrelin receptors in the brain, leading to harmful mental side effects, such as stress-induced vulnerability to enhanced fear.
It is also recommended that you avoid ibutamoren if you have cancer, as growth hormone and IGF-1 have the potential to promote cancer growth. People taking ibutamoren should also be careful of their carbohydrate intake, and regularly check their insulin and blood sugar levels.
How to Get Started with Ibutamoren
Currently, ibutamoren is available online as a research chemical, as well as by prescription from qualified wellness professionals. Its typical application is in the form of an orally-administered drug, which you take once a day to promote growth hormone synthesis. However, it is best to consult hormone replacement specialists before starting a regimen of ibutamoren.
This content was reviewed by Dr. Gary Kawesch. Dr. Kawesch graduated from Yale University, getting his degree in Molecular Biophysics and Biochemistry. He then got his medical degree at the UCLA School of Medicine. He completed his internship in internal medicine at USC’s Huntington Memorial Hospital in Pasadena, and his ophthalmology residency at the UCLA’s Jules Stein Eye Institute. For over 18 years, Dr. Kawesch was one of the foremost ophthalmic surgeons in the US and has consulted with and was a team doctor for seven professional sports teams in California. He continues to work with the Oakland Raiders. He trained with the American Academy of Anti-Aging Medicine and helps men increase their vitality, lifespan and overall healthspan.