Ibutamoren Mesylate (MK-677) stimulates growth hormones to aid muscle growth. However, studies have found other interesting uses & side effects. Read on to find out what these potential benefits are, whether ibutamoren can help you, and how to deal with potential side effects.

Disclaimer: By writing this post, we are not recommending this drug. Some of our readers who were already taking the drug requested that we commission a post on it, and we are simply providing information that is available in the clinical and scientific literature.

What is Ibutamoren?

Ibutamoren is frequently discussed on online forums for its muscle-building properties. It is available over the counter and used by those wishing to increase their growth hormone levels.

However, clinical studies of this compound are relatively few. In the text below, we will highlight what is known about ibutamoren so far.

Ibutamoren (also known as ibutamoren mesylate or MK-677), promotes the secretion of the growth hormone (GH) and increases insulin-like growth factor 1 (IGF-1) [1, 2].

Ibutamoren increases growth hormone levels by mimicking the action of the hormone ghrelin and binding to one of the ghrelin receptors (GHSR) in the brain. Activated GHSR stimulates growth hormone release from the brain.

GHSR is found in brain regions that control appetite, pleasure, mood, biological rhythms, memory, and cognition [3]. Therefore, we can expect that ibutamoren may also affect these functions. However, so far, clinical studies describe only the effects ibutamoren has on appetite – and as expected, like ghrelin, ibutamoren increases it.

A great thing about ibutamoren is that it increases growth hormone levels with little or no increase in other hormones, such as cortisol [4, 5]. Cortisol suppresses the immune system, reduces wound healing, and impairs learning and memory, and it’s usually not good to have this hormone elevated.

Potential Uses of Ibutamoren

1) Building Muscle

Ibutamoren is frequently used as an anabolic substance, to increase lean body mass i.e. create bigger muscles. It is orally active and can be taken once a day. These are all benefits compared to other growth hormone stimulators.

As previously mentioned, ibutamoren increases growth hormone levels and IGF-1 [1, 2]. Both growth hormone and IGF-1, in turn, increase muscle mass, muscle strength, and reduce body fat [6, 7].

In 24 obese men, a two-month treatment (double-blind randomized controlled trial) with ibutamoren increased lean mass, and transiently increased basal metabolic rate (BMR) [8].

2) Muscle Wasting

In a study (double-blind randomized controlled trial) in eight food-deprived healthy volunteers, ibutamoren reversed diet-induced protein loss [9], that could cause muscle wasting.

In 123 elderly patients with hip fracture (randomized controlled trial), ibutamoren improved gait speed, muscle strength and reduced the number of falls [10].

3) Bone Density

Growth hormone (GH) increases bone turnover and eventually bone density [11]. However, because of the increased turnover in subjects treated with growth hormone, bone density can initially decrease before increasing [2]. Basically, it takes time (> 1 year) to see the bone density increase.

In 24 healthy obese male volunteers, ibutamoren increased bone turnover (double-blind randomized controlled trial) [12].

In 187 elderly adults (65 years or older), ibutamoren increased bone building, as measured by osteocalcin, a marker of bone turnover in multiple studies (3 double-blind randomized controlled trials) [11].

In one study (double-blind randomized controlled trial) with 292 post-menopausal women, ibutamoren increased bone mineral density, which helps increase bone strength and prevent osteoporosis [13].

4) Sleep

A study (double-blind randomized controlled trial) showed that in both younger and elderly subjects, ibutamoren improved sleep quality and REM (rapid eye movement) sleep duration [14].

Apart from scientific studies, there have been many reports of subjective improvements in sleep quality, across various online forums.

5) Longevity

Growth Hormone (GH) secretion and muscle mass both decline from mid-puberty throughout life [2].

In a study with 65 elderly men and women (double-blind randomized controlled trial), daily ibutamoren increased GH and IGF-1 levels to those of healthy young adults without serious adverse effects [2]. IGF-1 is known to have beneficial effects on longevity [15, 16].

In another study with 24 obese males (double-blind randomized controlled trial), ibutamoren rejuvenated the growth hormone profile [8].

6) Nootropic Effects

Some people use ibutamoren as a nootropic because it acts on the ghrelin receptor, which has nootropic effects. You can read more about these effects in the post on ghrelin. Science is, however, yet to study if and how ibutamoren affects cognitive performance.

Two indirect mechanisms by which ibutamoren can improve brain function:

  • Ibutamoren increases IGF-1, which is known to improve memory and learning [1718].
  • Ibutamoren also increases REM sleep duration and sleep quality [14]. And we know that sleep is essential for good cognitive function [19].

A study (multicenter double-blind randomized controlled trial) questioned the association of low IGF-1 and Alzheimer’s disease, and whether ibutamoren could be of help. However, in this study, ibutamoren was ineffective at slowing the progression of Alzheimer’s in humans [20].

7) Growth Hormone Deficiency

Ibutamoren can increase growth hormone, IGF-1, and IGFBP-3 levels in children with growth hormone deficiency. Furthermore, these effects are achieved without changing the concentrations of prolactin, glucose, triiodothyronine (T3), thyroxine (T4), thyrotropin, cortisol or insulin [21].

In severely GH-deficient men, ibutamoren increased IGF-1 and growth hormone, with no significant changes in cortisol, PRL, and thyroid hormone levels. However, insulin and glucose were increased (double-blind randomized controlled trial) [22].

8) Wound Healing and Tissue Regeneration

Growth hormone increases tissue regeneration and wound healing [23, 24], so ibutamoren may help with these.

There are individual reports of ibutamoren being helpful, but scientific studies are lacking.

9) Hangovers

This one is anecdotal, but people report curing hangovers with ibutamoren.

Side Effects of Ibutamoren

The most frequent side effects of ibutamoren are an increase in appetite and transient, mild lower extremity edema and muscle pain [2].

Several studies report an increase in fasting blood glucose and a decrease in insulin sensitivity [2, 22].

These side effects are similar to those observed in people with elevated growth hormone levels, mainly joint pain and insulin resistance [25, 26].

Although most studies report little or no side effects, one study was terminated because of serious adverse events. In elderly patients with hip fracture, ibutamoren elevated blood pressure, blood glucose and HbA1c, and there were cases of congestive heart failure [10]. The patients experiencing congestive heart failure were over 80 and had a history of prior heart failure.

It would be prudent to watch your carbohydrate intake and regularly check blood sugar and insulin levels while taking ibutamoren.

As an anabolic, ibutamoren should be avoided if you have cancer. Both growth hormone and IGF-1 may promote cancer growth.

We would not recommend taking ibutamoren if you are Th1 dominant since growth hormone has immune stimulatory properties.

You can’t perform your best in the weight room or the boardroom without great, restorative sleep. Biohacking Insomnia is the most comprehensive sleep guide ever published with all the tips you need to maximize your time sleeping so you’re at your peak while you’re awake.

Buying Ibutamoren

There are some vendors who sell Ibutamoren in the United States. You can get 10% off by using the code “selfhacked”.

This section contains a sponsored link, which means that we may receive a small percentage of profit from your purchase, while the price remains the same to you. The proceeds from your purchase support our research and work. Thank you for your support.

We at SelfHacked advise speaking to a doctor before taking any drug, especially an unscheduled drug with limited long-term safety data in humans.

About the Author

Biljana Novkovic - PHD (ECOLOGICAL GENETICS) - Writer at Selfhacked

Dr. Biljana Novkovic, PhD

PhD (Ecological Genetics)

Biljana received her PhD from Hokkaido University.

Before joining SelfHacked, she was a research scientist with extensive field and laboratory experience. She spent 4 years reviewing the scientific literature on supplements, lab tests and other areas of health sciences. She is passionate about releasing the most accurate science & health information available on topics, and she's meticulous when writing and reviewing articles to make sure the science is sound. She believes that SelfHacked has the best science that is also layperson-friendly on the web.

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