Titus Thorne

Last Updated August 20, 2021

Titus Thorne

 August 20, 2021

Should you be worried about MK-677 side effects?

Well, it’s true that MK-677 has some potential side effects. But all the research so far suggests that this research compound is generally well-tolerated and safe.

MK-677 is increasingly being researched for bodybuilding and anti-aging applications, due to its easy oral administration and ability to significantly increase growth hormone levels in the blood. That, in turn, leads to a ton of potential benefits including increased muscle mass, fat burning, denser bones and even better sleep.

But it’s always important to consider the safety profile of any new chemical, especially one with such potentially powerful benefits.

We’ll do that here. Read on for a review of the research literature on the side effects of MK-677 and what it could mean for your research and test subjects.

Buy MK-677 from the #1 online Peptides vendor in the world: Peptides Sciences

Disclaimer: ResearchPeptides.org contains information about products that are intended for laboratory and research use only, unless otherwise explicitly stated. This information, including any referenced scientific or clinical research, is made available for educational purposes only. ResearchPeptides.org makes every effort to ensure that any information it shares complies with national and international standards for clinical trial information and is committed to the timely disclosure of the design and results of all interventional clinical studies for innovative treatments publicly available or that may be made available. However, research is not considered conclusive. ResearchPeptides.org makes no claims that any products referenced can cure, treat or prevent any conditions, including any conditions referenced on its website or in print materials.

What Is MK-677?

MK-677, also called Ibutamoren, is a non-peptide chemical substance that mimics the body’s Ghrelin [1] and stimulates the release of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) [2].

Both GH and IGF-1 play an essential role in a number of your body’s processes. They’re used at the cellular level to help cells regenerate and synthesize new tissues [3]. We need these hormones to help our body regulate itself and stay healthy. They help us build muscle, burn fat and repair ourselves [4, 5].

Most people produce enough GH and IGF-1 on their own when they’re young. But production slows down in old age, which is part of the reason that the body doesn’t work as well — it takes longer to heal, it’s harder to build muscle and we don’t sleep as well [6, 7]. And for people with GH deficiency, they may naturally run low on GH.

One of the proposed treatments for low GH is to simply supplement it directly. But it turns out that shocking the system with GH comes with intense side effects.

Instead, it appears that there are fewer adverse effects for the body when it’s supplemented with substances that stimulate the body to secrete its own GH [8, 9].

There are a number of these different chemicals; as a group, they’re called “growth hormone secretagogues.” What they have in common is that they upregulate the production, secretion and transmission of GH and IGF-1 throughout the body.

MK-677 is one of those GH secretagogues that has been consistently found to result in a significant increase in the body’s growth hormone levels.


MK-677 Benefits

What are the benefits of MK-677?

Well, its primary effect is that it increases GH levels. This is potentially beneficial for individuals that have a GH deficiency or who otherwise have low GH levels.

It really does work, too. Study after study has found that MK-677 test subjects subsequently have statistically and clinically significant increases in their blood GH levels [10, 11, 12, 13].

But it’s more than just GH. Indeed, GH is just the intermediary to the other benefits that test subjects could potentially notice in their everyday life. Some of those include:

  • Increased muscle mass. GH has been found to lead to significantly increased muscle mass in several clinical trials [4, 5]. Since MK-677 boosts GH, it’s no wonder that the early research suggests that it, too, leads to significant increases in muscle development in some populations, including obese individuals [13]. It also seems to improve muscle strength and prevents muscle wasting [14].
  • Fat burning. GH plays an important role in burning fat. While research on MK-677 has not conclusively established its fat-burning potential, some research has found that MK-677 helps increase resting metabolic rate [13].
  • Denser bones. Bone fractures from falls are actually among the most common serious injuries for the elderly. Fractures occur because bones tend to lose density as we age. MK-677 has been found to help reverse bone mineral loss and lead to denser bones [15, 16] and even reduce the number of falls [14].
  • Improves sleep. GH has long been associated with better sleep. Research on MK-677 supports that link, finding that the substance improves the length of Stage IV and REM sleep [17].

It’s important to note that direct research on MK-677 is still lacking, so these are only potential benefits. Still, the results firmly support the effectiveness of MK-677 on increasing GH levels. And the research on the effect of GH on the body is much clearer.

So while caution is warranted in interpreting the research literature, we can still have some confidence in the beneficial effects of MK-677.

MK-677 Side Effects

Great, but what about MK-677 side effects?

That’s the million-dollar question.

We should preface this section by issuing the following caveat: The research is still being done. We don’t know everything. Prescription medications that you buy at the pharmacy have undergone very comprehensive (and expensive) clinical testing to determine exactly what the side effects are. That requisite testing hasn’t been done for MK-677.

Still, what we do know looks promising.

There have been several studies of MK-677 on up to several hundred individuals, including the elderly [10, 11, 15, 16]. In those studies, there have not been any serious adverse effects linked to MK-677.

So that’s good news.

Short-Term, Mild Side Effects

Still, studies have linked MK-677 to several mild and uncomfortable side effects [10, 11, 15, 16]. It appears that MK-677 can occasionally lead to:

  • flushing of the face (lasting 3 to 5 minutes)
  • increase in appetite
  • headache
  • diarrhea
  • dry skin
  • night sweats
  • numbness and tingling
  • abdominal pain
  • edema
  • muscle pain

Are There Serious Adverse Reactions From Taking MK-677?

Those are all fairly mild side effects… but are there more serious side effects?

One particularly worrying side effect is that MK-677 — and GH itself — seems to influence blood glucose and insulin. Several studies have noted decreases in insulin sensitivity and increases in blood glucose as a result of using growth hormone secretagogues [18, 19, 20].

For most healthy individuals, this may not be an issue. But individuals who are diabetic, pre-diabetic or otherwise insulin-sensitive should refrain from participating in research on MK-677.

Another concerning finding was that in one study of elderly patients with hip fractures [14], MK-677 ibutamoren appeared to elevate blood pressure for some individuals. There were even cases of heart failure. It’s not clear that these cases were caused by MK-677 (the patients were all over 80), but this should still be registered as a concerning finding.

Long-Term Side Effects

There have not been many long-term studies of the use of MK-677. So whether there are long-term side effects is still an open question.

The few studies that do exist did not note any long-term side effects. These have studied the use of MK-677 over two years [18] and 18 months [16] respectively.

Still, even though the available evidence suggests that it appears safe over a couple of years, we need to remember that the research isn’t clear yet and so caution is warranted.

Growth Hormone and Cancer

At this stage, there is absolutely no evidence of any link between MK-677 administration and cancer.

But there have been studies that suggest GH and IGF-1 could promote the growth of cancerous cells [21]. This makes sense: GH promotes cell growth, so it also may promote the growth of cancerous cells, too.

Researchers should bear this with extreme consideration, and refrain from administering all GH secretagogues (MK-677 included) to subjects with any history or significant risk of cancer.

Side Effects Are Dose-Dependent

It’s important to note that the side effects of MK-677 appear to be dose-dependent. That means that as the dose increases, the likelihood that the test subject will experience side effects also increases.

That has an important implication for test subject safety: Smaller doses are likely safer.

In general, starting a dosing protocol with a smaller dose, and then increasing it gradually, may decrease the chance of experiencing adverse effects and side effects.


 MK-677 Dosage Guide

How do researchers dose MK-677 for their test subjects?

It varies from study to study, but the majority of published studies currently use a dosing protocol that is consistent with the following:

  • Between 10 mg and 50 mg. 25 mg seems to be the most common dose for test subjects that is used in the currently published scientific literature.
  • Administered orally. Virtually all studies on human subjects use MK-677 orally.
  • Administered once per day. The MK-677 half life is about 24 hours, so it is usually taken daily. It can be administered during the day or before bed.
  • Most effective on an empty stomach. Many studies administer it 2 hours after eating.

MK-677 Cycle?

Should test subjects be given MK-677 on a cycle?

Most researchers do cycle their participants, yes. Cycles typically seem to be:

  • between 2 and 8 weeks
  • with a few weeks to a month off.

However there has been at least one study of much longer duration — up to 24 months — of daily use [22]. In those studies MK-677 appeared to be well-tolerated, although it’s not clear what the long-term effects might have been.
The typical cycle does seem to be 2 to 8 weeks for most short-term research on MK-677, but perhaps longer is also safe. More research is needed to say for sure.

Where To Buy MK-677 Online | 2021 Guide

To minimize the risks of MK-677 research-related side effects, you should, at the very least, ensure that you’re working with a pure product.

Not only is high-quality MK-677 essential for trustworthy results, but it’s also for safety: The fewer impurities in your substance, the less risk you’re taking with the health of your test subjects.

The problem is that not all vendors are equally trustworthy. Some are selling products that are riddled with impurities.

Fortunately, we’ve already gone through the major suppliers. We know the landscape. If you want to ensure that you’re getting a high-quality, research-grade product, go for Science.bio.

Here’s what we like about them:

  • Great products. They really do have a pure product. And they can prove it, too: They get independent labs to analyze their products, and then they post the results online. It’s very transparent. At the moment, their MK-677 is available in either powder or solution form.
  • Great prices. Science.bio has the best prices you’ll see for a legitimate, US-made product. If you’re looking for value, you’ll find it at Science.bio
  • Great customer service. We’ve rarely had an issue with orders, but we know that if we do, we can get in touch and they’ll make it right. They always respond, and their service staff members are lovely.
  • Secure, reliable shipping. They ship all orders within 24 hours, and your order will get to you within a week if you’re located in the US. If you live elsewhere, it’ll take a bit longer but you’ll still get it within a reasonable time.

Buy MK-677 from our #1 recommended vendor...

Side Effects of MK-677 | Verdict

That was a lot to digest. So should you still be concerned about MK-677 side effects?

You definitely should be aware of them. All prudent researchers seriously consider the potential adverse effects of the substances they work with. This is especially important since there currently isn’t enough research available for us to properly understand all the side effects — especially the long-term ones — of MK-677.

But so far, the research suggests that MK-677 is generally well-tolerated and rarely leads to serious adverse effects.

Sure, don’t give it to test subjects that need to be concerned with their blood sugar (like diabetics) or those with a history of cancer. But in general, researchers can and do use MK-677 with human test subjects without issue.

So be cautious with your research … but feel confident that you’re in good company with others trying to understand this promising GH secretagogue.



  1. Patchett, A. A., Nargund, R. P., Tata, J. R., Chen, M. H., Barakat, K. J., Johnston, D. B., … & Hickey, G. (1995). Design and biological activities of L-163,191 (MK-0677): a potent, orally active growth hormone secretagogue. Proceedings of the National Academy of Sciences, 92(15), 7001-7005.
  2. Cassoni, P., Papotti, M., Ghè, C., Catapano, F., Sapino, A., Graziani, A., … & Muccioli, G. (2001). Identification, characterization, and biological activity of specific receptors for natural (ghrelin) and synthetic growth hormone secretagogues and analogs in human breast carcinomas and cell lines. The Journal of Clinical Endocrinology & Metabolism, 86(4), 1738-1745.
  3. Liu, H., Bravata, D. M., Olkin, I., Friedlander, A., Liu, V., Roberts, B., … & Hoffman, A. R. (2008). Systematic review: the effects of growth hormone on athletic performance. Annals of Internal Medicine, 148(10), 747-758.
  4. Welle, S., Thornton, C., Statt, M., & McHenry, B. (1996). Growth hormone increases muscle mass and strength but does not rejuvenate myofibrillar protein synthesis in healthy subjects over 60 years old. The Journal of Clinical Endocrinology & Metabolism, 81(9), 3239-3243.
  5. Kim, K. R., Nam, S. Y., Song, Y. D., Lim, S. K., Lee, H. C., & Huh, K. B. (1999). Low-dose growth hormone treatment with diet restriction accelerates body fat loss, exerts anabolic effect and improves growth hormone secretory dysfunction in obese adults. Hormone Research in Paediatrics, 51(2), 78-84.
  6. Salomon, F., Cuneo, R. C., Hesp, R., & Sönksen, P. H. (1989). The effects of treatment with recombinant human growth hormone on body composition and metabolism in adults with growth hormone deficiency. New England Journal of Medicine, 321(26), 1797-1803.
  7. Rudman, D., Feller, A. G., Nagraj, H. S., Gergans, G. A., Lalitha, P. Y., Goldberg, A. F., … & Mattson, D. E. (1990). Effects of human growth hormone in men over 60 years old. New England Journal of Medicine, 323(1), 1-6.
  8. Bowers, C. Y., Alster, D. K., & Frentz, J. M. (1992). The growth hormone-releasing activity of a synthetic hexapeptide in normal men and short statured children after oral administration. The Journal of Clinical Endocrinology & Metabolism, 74(2), 292-298.
  9. Penalva, A., Carballo, A., Pombo, M., Casanueva, F. F., & Dieguez, C. (1993). Effect of growth hormone (GH)-releasing hormone (GHRH), atropine, pyridostigmine, or hypoglycemia on GHRP-6-induced GH secretion in man. The Journal of Clinical Endocrinology & Metabolism, 76(1), 168-171.
  10. Chapman, I. M., Pescovitz, O. H., Murphy, G., Treep, T., Cerchio, K. A., Krupa, D., … & Thorner, M. O. (1997). Oral administration of growth hormone (GH) releasing peptide-mimetic MK-677 stimulates the GH/insulin-like growth factor-I axis in selected GH-deficient adults. The Journal of Clinical Endocrinology & Metabolism, 82(10), 3455-3463.
  11. Chapman, I. M., Bach, M. A., Van Cauter, E., Farmer, M., Krupa, D., Taylor, A. M., … & Thorner, M. O. (1996). Stimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretagogue (MK-677) in healthy elderly subjects. The Journal of Clinical Endocrinology & Metabolism, 81(12), 4249-4257.
  12. Chapman, I. M., Hartman, M. L., Pezzoli, S. S., & Thorner, M. O. (1996). Enhancement of pulsatile growth hormone secretion by continuous infusion of a growth hormone-releasing peptide mimetic, L-692,429, in older adults–a clinical research center study. The Journal of Clinical Endocrinology & Metabolism, 81(8), 2874-2880.
  13. Svensson, J., Lonn, L., Jansson, J. O., Murphy, G., Wyss, D., Krupa, D., … & Bengtsson, B. A. (1998). Two-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure. The Journal of Clinical Endocrinology & Metabolism, 83(2), 362-369.
  14. Adunsky, A., Chandler, J., Heyden, N., Lutkiewicz, J., Scott, B. B., Berd, Y., … & Papanicolaou, D. A. (2011). MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study. Archives of Gerontology and Geriatrics, 53(2), 183-189.
  15. Murphy, M. G., Bach, M. A., Plotkin, D., Bolognese, J., Ng, J., Krupa, D., … & Gertz, B. J. (1999). Oral Administration of the growth hormone secretagogue MK‐677 increases markers of bone turnover in healthy and functionally impaired elderly adults. Journal of Bone and Mineral Research, 14(7), 1182-1188.
  16. Murphy, M. G., Weiss, S., McClung, M., Schnitzer, T., Cerchio, K., Connor, J., … & MK-677/Alendronate Study Group. (2001). Effect of alendronate and MK-677 (a growth hormone secretagogue), individually and in combination, on markers of bone turnover and bone mineral density in postmenopausal osteoporotic women. The Journal of Clinical Endocrinology & Metabolism, 86(3), 1116-1125.
  17. Copinschi, G., Leproult, R., Van Onderbergen, A., Caufriez, A., Cole, K. Y., Schilling, L. M., … & Van Cauter, E. (1997). Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man. Neuroendocrinology, 66(4), 278-286.
  18. Nass, R., Pezzoli, S. S., Oliveri, M. C., Patrie, J. T., Harrell Jr, F. E., Clasey, J. L., … & Thorner, M. O. (2008). Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Annals of Internal Medicine, 149(9), 601-611.
  19. Denko, C. W., & Boja, B. (2001). Growth hormone, insulin, and insulin-like growth factor-1 in hypermobility syndrome. The Journal of rheumatology, 28(7), 1666-1669.
  20. Holly, J. M. P., Amiel, S. A., Sandhu, R. R., Rees, L. H., & Wass, J. A. H. (1988). The role of growth hormone in diabetes mellitus. Journal of Endocrinology, 118(3), 353-364.
  21. Weroha, S. J., & Haluska, P. (2012). The insulin-like growth factor system in cancer. Endocrinology and Metabolism Clinics, 41(2), 335-350.
  22. Nass, R., Pezzoli, S. S., Oliveri, M. C., Patrie, J. T., Harrell Jr, F. E., Clasey, J. L., … & Thorner, M. O. (2008). Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Annals of Internal Medicine, 149(9), 601-611.

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