MK 677 (Nutrobal/Ibutamoren): Dosage, Results, Side Effects & Reviews

Ibutamoren (developmental code name MK-677) is an orally-active growth hormone secretagogue and ghrelin receptor agonist being researched as a potential treatment for growth hormone deficiency and sarcopenia [RRRRR].

It was originally created to treat muscle wasting disorders such as osteoporosis. When clinical trials began, researchers noticed that it drastically increases the amount of IGF-1 and HGH in humans.

As you may know, increased HGH and IGF-1 levels provide a whole host of benefits in athletic performance. In this article we will go through everything you need to know about MK 677, including benefits, side effects, dosages, before and after pictures, where to buy, and also an FAQ.


What Is Ibutamoren (MK-677)?


Mk-677 is a potent growth hormone (GH) secretagogue, which mimics GH’s stimulating action of ghrelin – an endogenous hormone. It has been studied over the past decade for the treatment of low levels of IGF-1, as well as growth hormone deficiencies in children and elderly adults. Interestingly, nutrobal has the advantage of being safer and less expensive than growth hormone.

Nowadays, athletes have started utilizing this potent compound as a performance enhancer to improve endurance, fat loss, and gaining muscle mass. As a result, due to the great amount of fake and under-dosed HGH that is circulated on the market, nutrobal has the potential to become a game changer.

A growth hormone secretagogue is simply a substance that signals the pituitary gland in your body to secrete more growth hormone.

MK-677 is orally bioavailable, therefore it can be swallowed (no injections needed) [R].

To date, there have been no viable orally bioavailable alternatives to synthetic human growth hormone injections.

Much like SARMs, it is non-steroidal, but contrary to popular belief, MK-677 is not a SARM in any capacity, despite commonly being thrown into that category.

MK-677 will not negatively affect natural testosterone levels or endocrine function in any capacity at all, as it does not suppress any male sex hormones.

MK-677 has a much longer shelf-life than reconstituted GH, and does not need to be stored in the fridge or freezer to prevent degradation [R].

Clinical trials are currently assessing how viable of a potential treatment MK-677 is for addressing growth hormone deficiencies, muscle wasting diseases, Osteoporosis and a myriad of other related conditions.

Growth hormone is secreted by the somatotrophes of the anterior pituitary gland in multiple pulses each day.

Growth hormone is released into the blood stream and then stimulates the liver to produce insulin-like growth factor-1 (IGF-1), which stimulates linear growth before epiphyseal fusion and also exerts several metabolic effects throughout life.

After ingestion, MK-677 increases somatotrophe secretion of GH via signalling the pituitary gland to secrete a sufficient amount of growth hormone [RR].

The most common cause of GH deficiency in childhood is believed to be caused by a lack of adequate stimulation of the pituitary gland by hypothalamic GHRH, which is why something like Ibutamoren which can systemically increase IGF-1 levels for 24 hours with a single oral dose is very promising for potential clinical use [R].

The likely mechanism of action following MK-677 administration is the activation of the ghrelin receptor by MK-677, with feedback by IGF-I preventing excess GH production [R].

The mechanism of action through which MK-677 promotes GH secretion is comparable to growth hormone releasing peptides like GHRP-6, GHRP-2, Ipamorelin and Hexarelin, with GHRP-6 being the most similar in regards to the amount of ghrelin receptor activation that occurs post-administration.

MK-677 does not stimulate a greater quantity of secretion events per day (number of GH pulsations), but rather it stimulates a greater total 24 hour GH production rate [R].

In other words, Ibutamoren can substantially increase the strength of each GH pulsation that occurs in the body.


Benefits Of Using MK 677

Here are some of the most notable benefits of using MK 677 in your performance enhancing stack:

Builds Muscle

Growth hormone (GH) can accelerate lipolysis, and has an an anabolic effect in muscle tissue by increasing insulin-like growth factor (IGF)-I and nitrogen retention [R].

In a 2 month study on 24 healthy obese men using 25 mg of MK-677 per day, 3 kg of lean muscle mass was gained in the MK-677 treated group compared to the placebo group.

According to a DEXA scan, total body fat did not change during the study, equating to a gain of 6.62 pounds of muscle in the MK-677 treated group [R].

It should be noted that this conclusion has limitations, due to the fact that intracellular water very likely contributed a fair portion of that “fat-free mass” that was gained.

In another study conducted on sixty-five healthy men and women ages 60-81, 25 mg MK-677 per day increased fat-free mass (FFM) by 1.6 kg relative to placebo.

The average lifetime loss of fat-free mass in adults is ~ 5.5, therefore MK-677 has exhibited the potential to offset aging induced catabolism by as much as 29% [R].

Increases Bone Density

In a 12 month study conducted on postmenopausal osteoporotic women, 25 mg of MK-677 per day increased bone mineral density and was well tolerated without any significantly concerning side effects [R].

In a 2 month randomized, double-blind, parallel, placebo-controlled study on 24 healthy obese men (ages 19-49), 25 mg of MK-677 per day increased markers of bone formation within the first 2 weeks, and increased serum osteocalcin levels at the 2 month mark.

Predictably, large increases in serum IGF-1 levels were also noted [R].

In a clinical study evaluating the changes in serum IGF‐I and markers of bone turnover in 187 elderly adults (65 years or older) lasting 2–9 weeks, dosages of 10-50 mg were administered once daily.

All treated individuals experienced increased bone turnover, regardless if they were healthy or functionally impaired men or women [R].

Fat Loss

Elevated levels of insulin like growth factor (IGF-1) and growth hormone lead to higher levels of fat loss (source). The same study we referenced above shows that at the end of 14 days, those taking MK677 lost a significantly more amount of fat than the control group. Athletes who take this compound will experience a faster rate of fat loss than normal.

Safe to Take Year Round

One of my favorite parts of using MK 677 is that it does not need to be cycled off and on. It does not suppress your body’s natural testosterone production and therefore it is not uncommon for people to never cycle off of this compound. There are a lot of accounts of people on the internet who run it for 6 months to a year at a time and have had no adverse side effects.

Personally, I stick to 8 to 12 weeks on, 4 weeks off. This rhythm works well with my body and training style and as of August 2020 I haven’t experienced any negative effects of utilizing this cycling frequency.

Reduced Recovery Time

By drastically elevating the amount of IGF-1 and HGH in your body, you will not need to take nearly as many rest days as you would naturally. In fact, many people who start using ibutamoren start training twice a day to take advantage of this benefit.

Better Sleep Patterns

One of the most important thing for anyone who is trying to gain muscle or lose fat is proper sleep. In fact, this study shows that not getting enough sleep can actually curb your weight loss and prevent you from achieving results. MK 677 helps your body reach a deeper sleep. While it does not make you fall asleep like a sleep aid will, it does make your sleep deeper and more resting.

A study with eight young subjects (18-30 years) and six older subjects (65-71 years) found that MK-677 was able to increase REM sleep by as much as 50% [R].

Many anecdotal logs report much deeper sleep as a result of MK-677 usage as well.


Natural Growth Hormone secretion downregulates with age, consequently lowering serum IGF-1 levels in the body, which results in significant lean muscle catabolism and increased mortality [RR].

By restoring GH and IGF-1 levels to that of young healthy adults, it is likely that a significant amount of muscle and bone degradation could be prevented entirely.

In a study conducted on sixty-five healthy men and women ages 60-81, 25 mg MK-677 treatment per day resulted in increases in GH and IGF-1 levels to levels seen in young adults [R].

In another study conducted on one hundred sixty‐one hip‐fracture patients aged 65 and older, 25 mg MK-677 treatment per day increased serum IGF‐I levels by 84% [R].

Higher levels of IGF-1 are also associated with longer telomere length (a generally accepted marker of aging) [R].

Improves Immune System

A study on mice showed that a growth hormone secretagogue could generally duplicate the same enhancement of the immune system observed by treating mice with synthetic GH injections.

Statistically significant changes in immunological parameters in the young and old mice treated with the growth hormone secretagogue were noted.

Tumor resistance increased substantially, and there were signs of anti-aging whereby a deficiency in the thymus in mice (a result of aging) was reversed entirely [R].

Currently, growth hormone injections are an approved treatment for treating muscle wasting caused by AIDS, and the findings in this study would suggest that a growth hormone secretagogue like MK-677 could fulfill a clinical need for AIDS patients and individuals undergoing chemotherapy and irradiation.

It would also have the obvious advantage of being orally bioavailable, whereas GH can only be administered via injection.

Hair, Skin, and Nails

Many people who take MK-677 report that their skin appears to glow, and their hair and nails seem healthier. This is because MK 677 increases collagen in the body which will help you look more youthful than normal. Many famous people have admitted to doing HGH to remain youthful – this compound allows you to get the same results.

IGF-1 has been shown to affect follicular proliferation and differentiation, remodelling of tissue, as well as the hair growth cycle itself.

More evidence is arising to suggest that IGF-1 plays an important role as a regulator in hair follicle biology.

It should be noted that patients with growth hormone (GH) deficiency resulting from defective hormone binding with low serum IGF-1 levels exhibit very sparse hair growth [R].

Anecdotally, several users of synthetic GH injections and Ibutamoren have reported a faster growth rate of their hair, as well as improved overall hair density.

Prevention Of Growth Hormone Deficiency

MK-677 has exhibited the ability to increase serum GH and IGF-1 levels to that of a young healthy adult, thus it was obviously desirable to assess if it could be a potential alternative treatment to growth hormone injections for those diagnosed with growth hormone deficiency.

In a study conducted on nine severely GH-deficient men ages 17-34 yr who had been treated for GH deficiency with GH during childhood, once daily dosages of 10 or 50 mg MK-677 or placebo were administered.

10 mg MK-677 increased serum IGF-1  levels by 52% on average, and increased GH levels by 79% on average.

50 mg MK-677 increased serum IGF-1 levels by 79% on average, and increased GH levels by 82% on average.

These improvements are indicative of Ibutamoren’s potential as an alternative form of treatment for GH deficiency during childhood [R].


Side Effects

Unlike steroids and other illegal anabolics, there are not very many side effects associated with MK 677 use. There are, however, some changes that can happen to your body due to elevated GH levels. These changes can be easily reversed by stopping usage. Here are some of the side effects of MK677:

Water Retention

When your body has high levels of HGH flowing through it, water retention can be a common reaction. The good news is that a lot of this water is held inside the muscles, similar to what creatine does. This is one of the ways that HGH can increase strength in athletes. With that being said, some water can be stored under the skin and therefore give a bloated appearance. We typically do not see water retention or bloating at doses of 25mg a day, so try to keep your dosage around that level.

You can also reduce bloating by taking a diuretic such as dandelion root extract.

Increased blood pressure is an indirect side effect resulting from edema, which is one of the most common MK-677 side effects [R].


While this is great for those who are on their winter bulk cycle, those who are trying to take advantage of MK 677’s anti catabolic effect might find this side effect annoying. There’s no way to deny it: ibutamoren will make you hungry. Luckily, this effect is temporary and typically curbs by itself in around 2 weeks. Because of this, we suggest starting your cycle 2 weeks before you start dieting in order to get the hunger out of the way first.

Besides acting as a potent growth hormone secretagogue, MK-677 is also an oral ghrelin mimetic.

Ghrelin is the “hunger hormone” that your stomach secretes in order to regulate your appetite.

By artificially stimulating the secretion of that hormone, the body is tricked into being hungry, even when it wouldn’t have been otherwise.

MK-677 has a very significant effect on the ghrelin receptor, more so than any other ghrelin receptor agonist with the exception of GHRP-6.

How MK-677 and GHRP-6 differ is that GHRP-6 is in and out of the body very quickly (half-life of 20 minutes), whereas MK-677 will simulate the actions of ghrelin for several hours, thereby resulting in greatly increased levels of hunger all day long [R].

While MK-677 has a positive effect on body composition, I don’t believe the clinical data takes into account how important diet adherence really is when it comes down to what will get someone in shape.

In almost all cases, having chronic ghrelin receptor stimulation would make it nearly impossible to stick to a strict caloric deficit in order to reap the true metabolic benefits that Ibutamoren can provide in the first place.

It’s easy to see why this compound is recreationally used so often as an appetite stimulant, as the ghrelin mimetic properties are incredibly potent.

Numbness in Hands or Feet

If you start to feel “pins and needles” in your hands and feet, do not panic. This is not a dangerous side effect, and a quick google search will show you this is a common side effect of growth hormone. While nobody knows why this happens, doctors agree that it’s not dangerous and has nothing to do with damaged nerves.


Whether or not MK 677 causes anxiety is currently up for debate, however the majority of experts (including myself) agree that pharmacologically it should NOT cause anxiety.

There are not any studies (as of August 2020) that list anxiety as a side effect, and reports of it on the internet are few and far between. It is much more likely that anxiety experienced on cycle is entirely situational.

In my own personal experience, my anxiety goes down while taking MK 677. The improvement in sleep quality and appetite seem to directly impact my mental health in a positive way. I’ve heard many others share the same.

One study on rats evaluated MK-677’s potential to cause enhanced levels of fear.

There is evidence to support that one of the ways ghrelin is modulated is through exposure to stress.

What this study intended to assess specifically was if rats would have a greater likelihood of experiencing fear and posttraumatic stress disorder (PTSD) when their ghrelin receptors are artificially stimulated 24/7 with a ghrelin receptor agonist (MK-677).

So, rats were continuously administered MK-677, and frightened constantly, and their difference in response (MK-677 treated vs non treated) was assessed.

Rats with chronic ghrelin elevation were found to have enhanced fear memory compared to baseline [R].

This same response has yet to be replicated in human trials, or in anecdotal logs.


PCT (Post Cycle Therapy)

MK-677 does not cause endocrine suppression, it doesn’t lower natural testosterone levels, and it doesn’t inhibit LH, FSH or SHBG [R, R].

It does not raise estrogen either, which has an indirect effect on testosterone suppression [R].

As MK-677 doesn’t suppress any sex hormones, or increase any antagonizing hormones, there is no hormonal suppression that occurs via MK-677 use, and therefore would not require a PCT phase.


Half-Life MK-677

The elimination half-life of MK-677 is 4.7 hours; with IGF-1 levels remaining elevated with a single oral dose for up to 24 hours [R].

Once per day dosing of MK-677 has proven to be a viable frequency of administration throughout all of the clinical studies to date.


Differences Between MK 677 VS HGH

The main differences between MK 677 vs HGH are:

  • MK 677 is taken orally, whereas HGH needs to be injected
  • MK 677 is available for sale over the county, whereas HGH requires a prescription
  • MK 677 can be taken once per day, whereas HGH requires multiple doses a day

Injections vs Oral

HGH needs to be injected under the skin (but not into your vein), while nutrobal is taken orally. For many people, this is a deciding factor when deciding which route to go. Most everyone will prefer the ease of using an oral solution rather than injecting.

With MK-677 exhibiting effects formidable to that of a modest dosage of pure GH in clinical trials, it is easy to see why it has garnered so much attention from those seeking performance enhancement.

MK-677 also has the advantage of being stable in room temperature, orally bioavailable, sustaining elevated IGF-1 levels 24 hours post-ingestion, and works via stimulating natural endogenous GH secretion, as opposed to exogenous synthetic GH injections which will increase serum GH levels irrespective of the body’s current endogenous production without a feedback loop to regulate that hormone levels stay within healthy limits.

Dosing Frequency

MK 677 needs to be taken orally once per day. HGH requires injections, and you need to inject frequently. In fact, many bodybuilders inject HGH up to 5 times per day!


Legitimate HGH is very expensive. With insurance, you can expect to pay $500 a month just in co pays, and without insurance you will be paying thousands of dollars per month for your prescription. MK 677 is a lot cheaper than HGH. The average cost of legitimate MK677 is between $50 to $100 a month.


MK-677 Review From Derek MPMD

I have used MK-677 a few times over the past couple years now.

Each time the results have been fairly dramatic, even while on moderate dosages of anabolic steroids.

In my experience, intramuscular water and nitrogen retention is more apparent with MK-677 than GH.

That can be a good and bad thing though, depending on the goals of the user.

Every time I have used MK-677, within a week my weight would jump up 7-10 pounds.

The only thing that I can think of that will make more of a dramatic difference in that short a span of time is Dianabol.

This isn’t necessarily a positive thing though, and can actually be seen as a negative, depending on the goals of the user as I mentioned above.

If I had to compare 25 mg of MK-677 to something I would compare the results to 2-3 iu’s of high quality generic GH paired with a few daily 100 mcg injections of GHRP-6 coupled with concurrent 100 mcg injections of Modified GRF (1-29).

I also experience ravenous hunger that makes it nearly impossible to adhere to a reasonable caloric intake.

This is due to MK-677’s interaction with the ghrelin receptor.

The incredibly heightened appetite is the main reason I avoid this compound now, as I cannot cut down to sub 10% body fat when I have above average levels of ghrelin receptor activation around the clock.

Its appetite stimulating effects seem to subside to a large extent after a few weeks of continuous use, which makes it more tolerable, but I now avoid using ghrelin mimetics entirely unless I am eating above maintenance.

I’ve also noticed that MK-677 seems to very significantly offset hair loss.

Every time I use MK-677, my hair grows much faster, and there is a remarkable improvement in my hairs overall density.

Areas that are normally more diffuse than I prefer fill in quite a bit, very quickly whenever I use MK-677.

It has become my candidate of choice among growth stimulators for hair loss prevention.

In terms of side effects, I have noticed some fairly significant lethargy from MK-677 (anything that raises GH and IGF-1 will do this), however, I was able to mitigate that to some extent by taking my daily dosage right before going to bed.

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