MK 677, also known as Ibutamoren, has gained popularity among bodybuilders and athletes due to its effect on growth hormone levels and IGF-1.
In this guide, we will provide answers to many common questions about Ibutamoren.
TABLE OF CONTENTS
What is MK 677?
Some people mistake MK677 for a SARM (Selective Androgen Receptor Modulator). In reality, it’s actually not a SARM, but a Growth Hormone secretagogue. Unlike SARMs, which target the androgen receptors much in the same way as anabolic steroids, Ibutamoren influences the levels of human growth hormone and IGF-1.
It does this by mimicking the hormone ghrelin in the brain. You may have heard about this hormone before as it is a key chemical in hunger.
Recently, there have been a few of these products to surface on the market, including Growth-Hormone-Releasing-Peptide-6 and Hexarelin.
One of the benefits of MK-677, compared to other growth hormone releasing substances, is that it doesn’t affect cortisol levels.
This is a huge advantage, because cortisol increases fat storage, anxiety and blood pressure. Ibutamoren does not have any of these unwanted effects.
What are the benefits of MK-677?
The benefits of MK-677 include muscle-building, reduced muscle wasting, better bone density, improved sleep, and anti-aging properties. It may also have nootropic effects and it can be beneficial in treating growth hormone deficiencies. Read on for a more in-depth look at these benefits.
Helps build muscle
Ibutamoren is frequently used as an anabolic substance to increase lean body mass. It is the only Growth Hormone secretagogue that is orally active.
Growth hormone stimulates muscle size and strength, and Ibutamoren has proven to effectively stimulate the secretion of GH as well as IGF-1 (Insulin-like Growth Factor).
Reduces muscle wasting
MK-677 has shown in recent studies to alleviate muscle wasting, even in a low protein diet. In one study a group of healthy young adults were tested to determine if MK-677 could reverse protein catabolism and the results proved to be quite positive. As a result, MK-677 is theorized to be a possible effective treatment for individuals who suffer from catabolic conditions.
Improves sleep
By increasing Growth Hormone, Ibutamoren can help improve sleep quality. We know from studies that it improves sleep quality by increasing the duration of the REM (Rapid Eye Movement) sleep.
Apart from scientific studies, there have been many reports of subjective improvements in sleep quality.
This is beneficial for multiple reasons, one of which is better recovery after working out.
No suppression of testosterone
Since Ibutamoren does not affect the androgen receptors, it doesn’t cause any suppression of testosterone. This means that there is no need for PCT after a cycle of MK-677.

MK 677 side effects
Now that we have covered the benefits of this compound, it is time to discuss the MK 677 side effects. Because Ibutamoren doesn’t have any androgenic properties, there is no suppression of testosterone associated with it.
However, this does not mean that MK677 side effects are non-existing. Possible side effects include:
- Water retention
- Increased hunger
- Reduced insulin sensitivity (rare)
- Headaches (rare)
Water retention
Water retention is a pretty common MK 677 side effect. However, most people do not experience this at all, and those that do, report it mainly during the first week of their cycle. It can easily be prevented or at least significantly reduced by simply drinking more water.
So if you notice water retention in your legs/feet or hands, make sure to increase your water intake. You will likely see that it will go away in a couple of days. If it doesn’t, there is no reason for concern as this side effect is mostly harmless and will be gone after your cycle anyway.
Increased hunger
An increase in appetite, or actually hunger, is the most famous “side effect” of MK 677. This can either be a benefit or a side-effect, depending on the intended goal.
If you want to prevent this effect as much as possible, take the dosage before going to sleep. When an increased appetite is desired by you, take the dosage in the morning. This effect wears off in a few weeks into the cycle anyway.
You should notice an increase in hunger in the first week or two. But some people don’t even experience this, we are all different so not everyone experiences this but most people do.
Reduced insulin sensitivity
Some people report that their insulin sensitivity got reduced on their MK 677 cycle. Very few people report this, but still, some do. This could be a problem for type 2 diabetes patients.
The good news is that clinical trials have researched this by measuring blood glucose levels. It turns out that MK 677 doesn’t actually change blood glucose levels at all, proving that Ibutamoren won’t reduce insulin sensitivity.
It is possible that the few that reported this, actually had a bunk product. This goes to show the importance of purchasing from a reliable source.
MK 677 Dosage and cycle length
Ibutamoren is used in dosages ranging from 10mg to 50mg per day.
Research has shown that 10mg is just as effective as 50mg for GH production, but IGF-1 levels are highly dose dependent.
Most users consider 25mg per day the optimal dose for MK-677, providing the most benefits with limited side effects.
how and when to take MK 677
The half-life of Ibutamoren is 24 hours, according to recent studies. This means that it can be taken in a single dose once a day, roughly at the same time. If you want to know “when to take MK677 during the day“, there are several options.
Some people take their dosage in the morning, others prefer the evening. When you take your dose in the morning, you can benefit from the fact that it will increase hunger, which means that you can gain weight faster. If you take it in the evening, you can prevent being hungry and instead get amazing sleep. As we all now, it is during sleep that recovery takes place.
It is also possible to split the dosage and take half of it in the morning and the other half in the evening.
Ibutamoren cycle length
A typical cycle for MK677 lasts between 8 and 16 weeks. Some users prefer to take it for much longer: Ibutamoren cycles up to 6 months are not uncommon. There are actually good reasons to take it for an extended period of time.
While the increase in growth hormone levels is pretty much instant and stable over time, IGF-1 levels take a while to build up. This basically means that the longer you take Ibutamoren, the more effective it is.
During clinical trials the participants where given 25 mg daily for a period of 2 years.
Week | MK-677 dosage |
1 – 8 | 25mg/day |
How long does it take to work?
You will notice a strong increase in appetite already during the first week. Some people would describe it as extremely hungry. During the second week, you should notice the improved sleep quality associated with Ibutamoren.
The anabolic effects of MK-677 will take longer to kick in. It takes at least 4 weeks to notice any difference in muscle mass or strength and these benefits will become more apparent when taken for an extended amount of time.
Is MK 677 legal
The legal status of MK677 is the same as that of SARMs and related compounds such as GW-501516 and SR-9009. As such, MK 677 is legal to buy and use in every country around the world, with one exception. In Australia you will need a doctor’s prescription for it because it’s a Schedule 4 prescription only compound.
Ibutamoren has not been approved for human consumption, and is currently still a investigational new drug. This means that it is only allowed to be sold as a research chemical, and not as a supplement.
For more information on the legal status of SARMs, read our blog post: Are SARMs legal in Europe?
How does Ibutamoren work?
Stacking MK 677
Ibutamoren is often stacked with SARMs and related compounds for optimal effect. MK-677 can be stacked with Cardarine or Stenabolic for cutting purposes.
A stack that combines MK-677, LGD-4033 and RAD-140 is great for bulking.
For more information, read our blog post: Stacking SARMs: The ultimate guide.
Frequently asked questions
Does MK-677 increase testosterone?
Unlike SARMs that bind to the androgen receptors, MK-677 does not influence testosterone levels.
How long does it take for MK 677 to kick in?
Some of the effects of Ibutamoren are felt almost instantly, such as a increase in appetite and better sleep. It usually takes several weeks before the effects on recovery and muscle growth are noticeable.